HK1204171B - Centralized ip address management for distributed gateways - Google Patents

Description

Centralized IP address management for distributed gateways

Technical Field

The present invention relates to centralized IP address management for distributed gateways. More particularly, the present invention illustratively relates to measures (including methods, apparatus and computer program products) for implementing centralized IP address management for distributed gateways.

Background

In modern communication systems, including both mobile and fixed networks, which are typically IP-based, a significant growth in data traffic is expected in the future. Accordingly, efforts to cope with such projected data traffic growth are being made in both IP-based mobile and fixed communication systems. Such efforts include, for example, optimization-related changes in current EPC network architectures.

It is noted that although reference is mainly made below to 3GPP mobile networks, such reference is made only as an example, and therefore similar considerations apply equally to other types of mobile networks and/or fixed networks.

As a method for coping with increasing data traffic, distribution of gateways (also referred to as "internet gateways") is applied. Such Gateways (GWs) to be distributed may for example comprise S/PGWs and GGSNs in the context of 3GPP mobile networks. Gateway distribution means providing various gateways, where each gateway serves a portion of the users or user traffic only for providing access to an external network such as the internet. Thereby, a more direct/optimized routing may be achieved, which reduces traffic latency and/or saves transportation costs, especially for local traffic (cache, CDN, mobile to mobile traffic), for example. The distribution of GWs allows for more efficient handling of large amounts of user traffic, since optimal routing reduces the use of transport resources, and content servers and caches can be located closer to the users.

However, the distribution of GWs and thus the increasing number of GWs and interfaces to/from such GWs makes network management more complex. This is because each GW needs to be configured and needs to maintain an interface to a different server, for example, for operation, management, or policy control. At the same time, such servers oftentimes require some configuration per GW, e.g., for security features, thus still increasing network management efforts in both deployment and continuous operation. The increased number of network nodes due to GW distribution thus adds complexity and provides a challenge to manageability of the network.

More specifically, GW distribution hinders methods such as centralization of network management and control functions, virtualization in network nodes and devices, and network virtualization and programmable networks that can also help facilitate handling increasing data traffic. Thus, while GW distribution may be beneficial in dealing with increasing data traffic, such approaches thus simultaneously hinder implementation and/or degrade effectiveness of other conceivable approaches in this regard.

This may be particularly applicable, for example, to IP address management including IP address assignment, as explained below.

Fig. 1 shows a schematic diagram of a conventional example of a general network architecture for internet access applicable in the context of gateway distribution.

As shown in fig. 1, an end user IP device or host, such as user equipment UE, is connected to the internet via an IP network through an access device (i.e. a base station in a mobile network or a modem in e.g. a fixed network). The access device is connected to an internet GW (e.g., PGW in 3GPP or GGSN, e.g., BRAS in fixed network) via an access network specific data traffic tunnel. This is where the point of IP address management for the host is performed, e.g. where the host is assigned an IP address and the host becomes visible in the internet (hence also called point of presence POP). IP address management may be implemented in cooperation with AAA and/or DHCP servers. Thus, the internet GW terminates the data traffic tunnel and manages the IP addresses for all hosts served thereby, which is equally the case for all internet GWs in the GW distribution environment.

Fig. 2 shows a schematic diagram of a conventional example of a 3 GPP-based network architecture for internet access applicable in the context of gateway distribution. That is, fig. 2 illustrates an EPS network architecture with 3GPP defined interfaces or reference points.

As shown in fig. 2, the general AD of fig. 1 is implemented by an LTE base station exemplified by an eNB, and the internet GW is implemented by an S/PGW. The basic underlying operating principle is the same as described above in connection with fig. 1. A Mobility Management Entity (MME) selects a GW, where a User Plane (UP) tunnel is established from an eNB to the GW. The tunnel may be implemented, for example, using the GTP protocol in 3 GPP-based mobile networks, although in fixed networks the tunnel may result from a pre-configured selection and a pre-configured connection.

Fig. 3 shows a schematic diagram of a conventional example of a 3 GPP-based network architecture for internet access that exhibits distributed gateways.

The 3 GPP-based network architecture according to fig. 3 may represent an overall view on an overall system consisting of a GW distribution on the basis of a plurality of 3 GPP-based network architectures according to fig. 2.

As shown in fig. 3, there are a plurality of internet GWs such as S/PGWs for providing internet access between the RAN (or other kind of access or connectivity network) and the internet. As explained above, each of these multiple internet GWs serves a certain number of users or hosts in terms of internet access, needs to be configured, and needs to maintain respective interfaces to MME, AAA and DHCP entities, as indicated by the dashed lines in fig. 3. In particular, IP address management including IP address assignment must be performed separately locally at any internet GW, for the user or host, respectively, of such a service.

Thus, in reducing network management efforts, it is desirable to improve the functionality of IP address management including IP address assignment in a network architecture having distributed gateways (or access routers) to connected hosts.

Disclosure of Invention

Various exemplary embodiments of the present invention are directed to solving at least some of the above problems and/or problems and disadvantages.

Aspects of exemplary embodiments of the invention are set out in the appended claims.

According to an exemplary aspect of the invention, there is provided a method comprising: the method comprises managing at the centralized controller entity internet protocol addresses for hosts linked with the plurality of distributed gateway entities via a first host-specific tunnel, and controlling the plurality of distributed gateway entities in accordance with the internet protocol address management from the centralized controller entity via a second host-specific tunnel on the basis of the managed internet protocol addresses for the hosts.

According to an exemplary aspect of the invention, there is provided a method comprising: providing a distributed gateway function for hosts linked via a first host-specific tunnel, acquiring control for internet protocol address management of the hosts from a centralized controller entity via a second host-specific tunnel, and supervising the internet protocol address management for the hosts via the first host-specific tunnel on the basis of the acquired control for internet protocol address management of the hosts.

According to an exemplary aspect of the invention, there is provided an apparatus comprising an interface configured to communicate with at least another apparatus, a memory configured to store computer program code, and a processor configured to cause the apparatus to perform: the method comprises managing at the centralized controller entity internet protocol addresses for hosts linked with the plurality of distributed gateway entities via a first host-specific tunnel, and controlling the plurality of distributed gateway entities in accordance with the internet protocol address management from the centralized controller entity via a second host-specific tunnel on the basis of the managed internet protocol addresses for the hosts.

According to an exemplary aspect of the invention, there is provided an apparatus comprising an interface configured to communicate with at least another apparatus, a memory configured to store computer program code, and a processor configured to cause the apparatus to perform: providing a distributed gateway function for hosts linked via a first host-specific tunnel, acquiring control for internet protocol address management of the hosts from a centralized controller entity via a second host-specific tunnel, and supervising the internet protocol address management for the hosts via the first host-specific tunnel on the basis of the acquired control for internet protocol address management of the hosts.

According to an exemplary aspect of the invention, there is provided a computer program product comprising computer executable computer program code configured to, when the program is run on a computer, for example a computer of an apparatus according to any of the above apparatus-related exemplary aspects of the invention, cause the computer to carry out a method according to any of the above method-related exemplary aspects of the invention.

The computer program product may comprise or may be embodied as a (tangible) computer-readable (storage) medium or the like on which computer-executable computer program code is stored and/or the program is directly loadable into the internal memory of the computer or a processor thereof.

Advantageous further developments or modifications of the above-described exemplary aspects of the invention are set out below.

As an exemplary embodiment of the present invention, centralized IP address management including IP address assignment for distributed gateways is provided.

Any of the above aspects enables improving the functionality of IP address management including IP address assignment in a network architecture having distributed gateways (or access routers) to connected hosts in terms of reducing network management efforts.

Thus, improvements are achieved by methods, apparatuses and computer program products enabling/implementing centralized IP address management for distributed gateways including IP address assignment.

Drawings

The invention will be described in more detail hereinafter, by way of non-limiting examples, with reference to the accompanying drawings, in which

Figure 1 shows a schematic diagram of a conventional example of a general network architecture for internet access applicable in the context of gateway distribution,

figure 2 shows a schematic diagram of a conventional example of a 3 GPP-based network architecture for internet access applicable in the context of gateway distribution,

figure 3 shows a schematic diagram of a conventional example of a 3 GPP-based network architecture for internet access presenting a distributed gateway,

figure 4 shows a schematic diagram of an example of a network architecture for internet access according to an exemplary embodiment of the present invention,

figure 5 shows a schematic diagram of a first exemplary process according to an exemplary embodiment of the present invention,

figure 6 shows a schematic diagram of a second exemplary process according to an exemplary embodiment of the present invention,

figure 7 shows a schematic diagram of a first example of a 3 GPP-based network architecture for internet access according to an exemplary embodiment of the present invention,

figure 8 shows a schematic diagram of a second example of a 3 GPP-based network architecture for internet access according to an exemplary embodiment of the present invention,

fig. 9 shows a schematic diagram of a third example of a 3 GPP-based network architecture for internet access according to an exemplary embodiment of the present invention, an

Fig. 10 shows a schematic diagram of an exemplary device according to an exemplary embodiment of the present invention.

Detailed Description

The invention is described herein with reference to specific non-limiting examples and what are presently considered to be conceivable embodiments of the invention. Those skilled in the art will appreciate that the present invention is by no means limited to these examples and may be applied more broadly.

It is noted that the following description of the invention and its embodiments refers primarily to specifications used as non-limiting examples for certain exemplary network configurations and deployments. That is, the present invention and its embodiments are described primarily in relation to 3GPP specifications, which serve as non-limiting examples for the applicability of certain exemplary network configurations and deployments, which serve as non-limiting examples for the exemplary embodiments so described. Thus, the description of the exemplary embodiments presented herein makes specific reference to the terminology directly related thereto. Such terms are used only in the context of the non-limiting examples presented and naturally do not limit the invention in any way. Rather, any other network configuration or system deployment, etc., may also be utilized so long as the features described herein are complied with.

In particular, the invention and its embodiments may be applicable in any fixed or mobile communication system and/or network deployment having an architecture of distributed gateways for internet access.

Various embodiments and implementations of the invention and aspects or embodiments thereof are described below using a number of variations and/or alternatives. It is generally pointed out that all described variants and/or alternatives can be provided alone or in any conceivable combination (likewise including combinations of individual features of the various variants and/or alternatives), according to certain needs and constraints.

In accordance with the exemplary embodiments of this invention, generally, there are provided (enabled/realized) measures and mechanisms for centralized IP address management including IP address assignment for distributed gateways.

In general, the present invention and its embodiments relate to the centralization of network management and control functions under the assumption of some level of GW distribution. Furthermore, the invention and its embodiments may facilitate virtualization in network nodes and devices and/or network virtualization and programmable networks.

In the following, the invention and its embodiments are described with reference to a mobile network, which is mentioned for illustrative purposes only as an example. It is therefore noted that the invention and its embodiments as described herein are equally applicable to fixed networks.

In addition, the following description is given for the case where the host/UE has only one PDN connection at a time, mainly a connection to the internet or any other external/proprietary network. In such a case, the distributed GW may be implemented by a combined S/PGW, as assumed, for example, in the following exemplary illustrations of fig. 6 to 8. However, it is noted that the invention and its embodiments as described herein are equally applicable to scenarios with multiple PDN connections for a host/UE.

Fig. 4 shows a schematic diagram of an example of a network architecture for internet access according to an exemplary embodiment of the present invention.

As shown in fig. 4, which illustrates, by way of example only, an EPS network architecture exemplified with 3GPP defined interfaces or reference points, it is evident that a central controller (i.e. a centralized controller entity) is introduced. The central controller according to an exemplary embodiment of the present invention interfaces the functionality of any one or more of the distributed (internet) gateway GWs like MME, AAA and DHCP servers etc. and the distributed (internet) gateways GW that provide internet access to their linked hosts, such as UE, respectively. As outlined below, the central controller according to an exemplary embodiment of the present invention employs part of the functionality of a conventional (internet) gateway, in particular in terms of IP address management including IP address assignment, and the (internet) gateway according to an exemplary embodiment of the present invention therefore lacks such functionality to be transferred to the central controller. Thus, as is apparent from a comparison of any of fig. 1 to 3 with any of fig. 4 and 7 to 9, (internet) gateways according to exemplary embodiments of the present invention are simplified in that they do not require any interface to AAA and/or DHCP servers/functions/entities. Thereby, the total number of required interfaces in the overall network architecture according to exemplary embodiments of the present invention is reduced, and the overall network architecture itself is simplified.

Thus, when reference is made below to a distributed GW (or access router), this means a physical GW (or access router) device that lacks functionality with respect to IP address management of hosts connected to it, but instead provides the functionality outlined herein to allow the functionality to be taken over by a central controller.

As shown in fig. 4, the centrally controlled is linked to the distributed (internet) gateway GW through a tunnel (indicated by the thick line) and a control interface (indicated by the dashed line), which may be dedicated for distributed GW control. According to an exemplary embodiment of the present invention, such a link between the linked central control and the respective distributed (internet) gateway GW may be realized by an interface, which may be referred to as S11+ interface, as indicated by the respective bold and dashed line pairs of the surrounding ellipsoid in fig. 4, as explained below.

A central controller according to an exemplary embodiment of the present invention is configured to manage (e.g., assign) IP addresses for hosts linked with a plurality of distributed gateway entities (GWs), and control the plurality of distributed gateway entities (GWs). Such control includes control in terms of internet protocol address management on the basis of managed internet protocol addresses for the hosts, which can be realized via the aforementioned tunnels (links). Such control may also include distributed gateway control via a control interface, which may be implemented by the aforementioned control interface (link). Any one of a plurality of distributed gateway entities (GWs) according to exemplary embodiments of the present invention is configured to provide a distributed gateway function for a host linked thereto, acquire (i.e., retrieve) control of IP address management (e.g., assignment) for the host from a central controller, and supervise the IP address management for the host on the basis of the acquired (i.e., retrieved) control of the IP address management for the host. They may furthermore be configured to acquire (i.e. obtain) distributed gateway control from the central controller and to control the traffic of the hosts on the basis of the acquired (i.e. obtained) distributed gateway control. The IP address management control can be obtained from the central controller via the aforementioned tunnel (link) (e.g. in a pull fashion from the perspective of the distributed GW), and the distributed GW control can be obtained from the central controller via the aforementioned control interface (link) (e.g. in a push fashion from the perspective of the central controller).

As outlined below, the tunnel between the central controller and the distributed GW (hereinafter referred to as the second (host-specific) tunnel) may be linked with the managed IP address of the host in question itself or any other conceivable identifier of the host in question.

Thus, the central controller according to an exemplary embodiment of the present invention has an IP management (assignment) function (in combination with a distributed GW control function). That is, the central controller according to an exemplary embodiment of the present invention manages (e.g., assigns or allocates) IP addresses to devices/UEs on behalf of the distributed GW or access router, thereby centralizing control functions that conventionally reside in the distributed GW or access router (such as the S/PGW in a 3 GPP-based architecture).

In addition, the central controller according to an exemplary embodiment of the present invention may have additional functionality, such as for example supporting charging of the interface (and its termination at the centralized controller). Thus, the central controller may perform e.g. charging record generation for offline charging or budget management for online charging, where it may rely on accounting messages that are part OF e.g. the OF protocol and sent to the central controller.

The central controller may also be regarded as a central/centralized gateway entity (provided in addition to the distributed gateway entities). The combination of a group (e.g., subset) of distributed GWs or access routers and a central controller may be considered a logical gateway entity according to an exemplary embodiment of the present invention.

In addition, according to an exemplary embodiment of the present invention, the distributed GW according to an exemplary embodiment of the present invention has a traffic checking and separating function. That is, any one of the distributed GWs according to the exemplary embodiments of the present invention can check traffic from hosts it serves and separate an "IP layer control message" from the traffic and relay the same to a central controller. The central controller can then receive (i.e., retrieve) these "IP layer control messages" and use them in accordance with IP address management (assignment) for the respective hosts. Traffic inspection according to exemplary embodiments of the present invention may be based on packet header information and does not require any deep packet inspection.

In a network architecture according to an exemplary embodiment of the present invention, interface-related aspects may be considered as follows.

From the MME perspective only, there is one GW (or S/PGW) represented by the central controller. As a result, the MME is connected to a central controller representing GW control functionality, for example, using a standardized S11 interface. The interface between the central controller and the distributed GWs or access routers may provide a subset of the standardized S11 interface functionality, and may also support some modifications and additions, depending on the actual implementation. This is the reason why it is referred to as S11+ in fig. 4 (and fig. 7 to 9 below). According to an exemplary embodiment of the present invention, the S11+ interface so designated may include a tunnel (usable for IP address management control) and a control interface (usable for distributed GW control). For example, the central controller may provide a message distribution function to the distributed GWs or access routers in a kind of proxy mode. In case the tunnels in the network architecture are operable according to the standardized GPRS Tunneling Protocol (GTP) as explained below, the central controller may provide message distribution functionality for S11 GTP-C control messages, while GTP-C is also a candidate protocol for the S11+ interface.

Note that, just as in the network architectures of fig. 1-3 above, the physically distributed GW still represents a point of presence (POP) for the terminal device/UE in terms of access to the internet or other proprietary/external network to which packets destined for the terminal device/UE are routed. Their location in the routing topology of the global internet or private/foreign networks therefore requires the management (e.g., assignment or allocation) of specific IP addresses to the terminal devices/UEs they serve. Although this functionality is therefore often located in each physical GW, it is located in the central controller according to an exemplary embodiment of the present invention. This separation and centralization of functionality to sites far from the POP will not change the route itself, but allow different types of optimization with respect to GW/POP selection and network management.

For example, the separation and centralization of IP address management functionality to a central controller is effective to alleviate the challenges of network architectures with distributed GWs, in particular in (central) network management and control.

According to exemplary embodiments of the present invention, it may be effectively utilized that a gateway or access router (such as S/PGW in 3 GPP) contains functionality that may be centralized, such as control plane operations/functions for IP address management. Otherwise those functionalities to be maintained in a distributed manner (at the POP), such as user plane operations/functions for user data forwarding between network interfaces, are maintained in the distributed gateways or access routers. Thereby, a preferred spread of operations/functions between the central domain and the local/distributed domains may be achieved.

As illustrated in fig. 7-9 below, the link between the host and the distributed gateway entity (GW) according to an exemplary embodiment of the present invention is implemented via a (first) host-specific tunnel, and the connection between the central controller according to an exemplary embodiment of the present invention and the distributed gateway entity (GW) according to an exemplary embodiment of the present invention is implemented via an interface link (e.g., S11+ interface) including a (second) host-specific tunnel and a control interface.

That is, a host/UE specific (e.g., GTP) tunnel may be established between an access device (such as a base station) and any distributed GW. In addition, host/UE specific (e.g., GTP) tunnels may be established between any distributed GW and the central controller (except for the control interface). Details regarding tunnel establishment are explained below.

Thus, existing tunnel-based concepts in the context of IP address management may be effectively utilized in accordance with exemplary embodiments of the present invention.

More specifically, IP address management for hosts such as, for example, mobile nodes, by a central controller may be implemented on the basis of such a tunneling concept. In the case of IPv6, a 3 GPP-defined allocation scheme "in tunnel" can be employed that is quite similar to a fixed network to allow similar IP stack functionality for fixed and mobile hosts. In the case of IPv4, a so-called "deferred IP address allocation" scheme may be employed, which also uses a User Plane (UP) tunnel between the UE and the GW to run IP address assignments with DHCP. In general, DHCP is equally applicable to IPv6 as well.

Fig. 5 shows a schematic diagram of a first exemplary process according to an exemplary embodiment of the present invention.

As shown in fig. 5, a process according to an exemplary embodiment of the present invention may include the following operations based on respective functions of respective entities, i.e., a central controller and (any one of) a distributed GW or an access router.

At a central controller, a process according to an exemplary embodiment of the present invention includes: the method comprises the steps of managing IP addresses for hosts linked with a plurality of distributed gateway entities via a first host-specific tunnel, and controlling the operation of the plurality of distributed gateway entities in accordance with the IP address management via a second host-specific tunnel on the basis of the managed IP addresses for the hosts. At the/any distributed gateway device providing distributed gateway functionality for hosts linked via a first host-specific tunnel, a process according to an exemplary embodiment of the invention comprises: an operation of acquiring control for IP address management of the host from the central controller via the second host-specific tunnel, and an operation of supervising IP address management for host traffic via the first host-specific tunnel on the basis of the acquired control for IP address management of the host.

Fig. 6 shows a schematic diagram of a second exemplary process according to an exemplary embodiment of the present invention.

As shown in fig. 6, a process according to an exemplary embodiment of the present invention may include the following operations based on respective functions of respective entities, i.e., a central controller and (any one of) a distributed GW or an access router.

In terms of distributed GW control, the central controller performs control of the plurality of distributed gateway entities via the aforementioned control interfaces. Such distributed GW control may include separate set-up/establishment of contexts (and/or (partial) sessions) and tunnels, etc. In this regard, a corresponding request or the like may be transmitted from the central controller to the respective distributed GWs. Also, dedicated parameters (which may be referred to as IP address management parameters) and/or specific triggers (the details of which are explained below) may be transmitted/signaled. The respective distributed GW may then perform the corresponding context (and/or (partial) session) and tunnel establishment etc. (upon request) and transmit its acknowledgement to the central controller, and the respective distributed GW may then control the host traffic accordingly.

The two messages exchanged in this regard relate to the control message part (e.g. GTP-C control part) of the S11+ interface.

Thus, the control interface part (e.g. GTP-C control part) of the S11+ interface, as indicated by the dashed lines in fig. 4 and 7 to 9, is thus used to control the distributed GW/GWs. This may include the setup/establishment of a context (and/or session) and the setup/establishment of the first and second tunnels. When the MME identifies only one GW, represented by the central controller, the central controller has a message distribution function to address different distributed GWs in accordance with distributed GW control.

In terms of its traffic splitting and control functions, the distributed GW may examine the traffic of the hosts it serves (i.e., on the first host-specific tunnel) and split the examined IP layer control messages from the host traffic and relay the split IP layer control messages to the central controller (i.e., via the second host-specific tunnel). That is, such "IP layer control messages" (which must be exchanged between the host/UE and the GW anyway) can be separated from the data traffic and can be relayed (i.e., tunneled) between the UP tunnel from the access device and the UP tunnel to the central controller. For other packets, the (e.g., GTP) tunnel from the access device terminates at the distributed GW, and user packets are routed to and from the external network/internet. This requires the distributed GW to check what UP traffic for "IP layer control messages" might specifically mention the signaling required for management (e.g., assignment or allocation) of IP addresses (including both IPv4 and IPv6 addresses), such as neighbor discovery protocol messages (e.g., route requests) and/or DHCP protocol messages.

In terms of its IP address management function, the central controller may receive (i.e., retrieve) (tunneled) IP layer control messages from host traffic from any one or more of the plurality of distributed GWs (i.e., via the second host-specific tunnel) and utilize the received (i.e., retrieved) IP layer control messages in managing IP addresses for the hosts. That is, the central controller controls the plurality of distributed GWs in accordance with IP address management on the basis of the thus managed (e.g., assigned) IP address for the host. Such control may be implemented, for example, in the form of transport/signaling of specific (IP layer) control messages and/or dedicated parameters (which may be referred to as IP address management parameters) tunneled to the respective distributed GW and/or specific triggers. Details of this are explained below.

Thus, IP layer control messages are exchanged between the distributed GWs and the central controller via the second tunnels, respectively. Each (second) tunnel between the central controller and any one of the distributed GWs is associated with a tunnel identifier (tunnel ID). Thus, the central controller may associate each received IP layer control message with the sending distributed GW via the tunnel ID of the tunnel carrying the respective message, and the central controller may associate information relating to the host in question (e.g. the UE) and the IP address (to be managed, e.g. assigned) with the tunnel ID, and the central controller may transmit the corresponding IP layer control message to the appropriate distributed GW. Information relating to a host (e.g., a UE) may include any conceivable host/UE identifier, such as, for example, an IMSI (e.g., when no IP address has been previously assigned to the host), an IP address (e.g., when an IP address has been previously assigned to the host), and so forth.

In view of the above, host-specific contexts may be established in accordance with the tunneling concept for IP address management according to exemplary embodiments of the present invention. That is, each host may have its own first and second tunnels.

Thus, the second tunnel to be used in accordance with IP address management according to an exemplary embodiment of the present invention may be linked to the managed IP address itself of the host in question or any other conceivable identifier of the host in question, such as any (radio) access network related (user/subscriber/host) identification, e.g. IMSI or the like.

The distributed GW is able to supervise IP address management for the hosts (i.e. via the first host-specific tunnel) on the basis of control obtained from (i.e. under control of) the central controller in accordance with IP address management. In such supervisory control, IP layer control messages may be forwarded to/from the host as appropriate.

The two messages in this regard relate to the IP address management control part of the S11+ interface.

The part of the exemplary procedure above the dashed line relates to the control interface (of the S11+ interface link) for distributed GW control, e.g., the GTP-C control part. The part of the exemplary procedure below the dashed line relates to the tunnel (of S11+ interface link) used for (in tunnel) IP address management control.

That is, as explained above, the (e.g., S11 +) interface link between the central controller and the one or more distributed GWs according to exemplary embodiments of the present invention includes both the control interface and the corresponding control message (e.g., GTP-C protocol) and the second host-specific tunnel and the corresponding control message.

As is apparent from the foregoing, exemplary embodiments of the present invention effectively utilize a central controller exhibiting centralized IP address management functionality, as compared to conventional solutions. Therefore, the GW/PGW does not terminate (e.g., 3GPP specific) signaling related to the attach procedure and does not ultimately implement IP address management.

According to an exemplary embodiment of the present invention, tunnel establishment may be implemented as follows.

As mentioned above, according to exemplary embodiments of the present invention, in addition to establishing a first tunnel between an access device in a host access or connectivity network and any distributed GW, a second tunnel is established between any distributed GW and a central controller, which is used to handle IP addressing issues away from the distributed GW. The two tunnels may be established simultaneously, for example, at session establishment.

In a 3 GPP-based system, the 3 GPP-defined procedures may be basically used for such tunnel establishment according to an exemplary embodiment of the present invention. During the host/UE attachment procedure to the network system, a (e.g. GTP) tunnel may be set up in case of session management messages. When there are co-located SGWs and PGWs, the PGW is native to the SGW and does not require an S5 interface setup for the tunnel between the SGW and the PGW. Thus, the central controller may be set up for the second tunnel using the S5 interface. Wherein the distributed GW may be in the role of SGW and the central controller may be in the role of PGW. The central controller may set its own IP address to the PGW address (which may be used for establishment of tunnels towards the distributed GW/GWs), for example in the S11+ message. In addition to this, dedicated parameters (which may be referred to as IP address management parameters) may be set by the central controller to signal and enable corresponding functions at the central controller and/or any distributed GW. More specifically, such dedicated parameters may indicate "remote IP address management/assignment and local SGi interface (local PGW)". Any distributed GW may still function as a PGW on the user plane and provide packet routing to external networks/internet.

According to an exemplary embodiment of the present invention, IP address assignment in the context of IP address management may be implemented as follows.

As usual, according to an exemplary embodiment of the invention, the IP address assignment may take place during the host/UE attachment procedure to the network system. The additional IP address may still be assigned later with the PDN connectivity procedure, e.g., when multiple networks are connected to the host/UE.

In a 3 GPP-based system, the 3 GPP-defined procedure may be basically used for IP address assignment according to an exemplary embodiment of the present invention. Standard 3GPP signaling messages between MME and SGW (i.e. on the S11 interface) are terminated in a centralized controller. For IPv6 bearers, the central controller assigns or allocates a unique interface identifier for the host/UE and sends it to the host/UE during the attach procedure via the S11 interface, the S1 interface and NAS session management signaling. After selection of the distributed GW/POP, the central controller assigns or allocates the UE IP address (in IPv6, prefix) from the available prefix/address range of the selected GW/POP (e.g., according to routing needs). For this purpose, the central controller may use functions and/or internal databases typically provided by AAA and/or DHCP servers.

As mentioned above, the central controller according to an exemplary embodiment of the present invention may trigger the context establishment in the selected distributed GW on the S11+ interface. This may be accomplished, for example, by the S11 "create session" message. The aforementioned dedicated parameters may indicate to the selected distributed GW the application of the remote IP address assignment at the central controller. The context establishment in the distributed GW may then activate the traffic checking and splitting functions in the distributed GW, as well as the tunnel between the distributed GW and the central controller. Thereby, it is enabled to check S1 (e.g. GTP) tunnels terminating in the distributed GW for IP control messages sent by the UE, which are often exchanged between the host and the first hop router. These messages may then be further tunneled to the central controller.

After establishment of the PDN connection (including, e.g., radio bearers, S1 GTP tunnel, etc.), the UE may send a Router Solicitation (RS) message (for IPv 6) to the network, e.g., as usual, to get an IPv6 address or a DHCP message for "deferred address allocation" to get an IPv4 address. In this regard, the central controller is in the role of a first hop router (and possibly even the only router towards the internet or external network) and ends the address assignment. This may be achieved, for example, by sending a Router Advertisement (RA) message or acting as a DHCP relay for DHCP based address assignment and sending a response in a second tunnel to the distributed GW and back to the UE. When IPv4 is used for PDN connections, IP L3 control message forwarding is only required by "deferred IPv4 address assignment" with DHCPv 4. Otherwise, host/UE specific ("out-of-band") signaling (e.g., on/over S11, S1, NAS/through S11, S1, NAS) has provided the IP address to the host/UE.

In the following, three examples of network architectures for 3GPP based network systems are given for illustrative purposes only as examples.

In any of the following fig. 7 to 9, it is apparent that as a general aspect according to an exemplary embodiment of the present invention, the S/PGW functionality may be separated into an S/PGW (control) part in the central controller and an S/PGW part in the distributed GW, and the IP address management function (which is illustrated as an IP address assignment function in fig. 7 to 9) is located at the central controller. That is, the exemplary embodiments of this invention enable separation of control plane and user plane functionality within a (logical) gateway entity, such as, for example, a (logical) PGW.

The central controller handles IP address management (such as IP address assignment) for the hosts/UEs, including IP layer signaling for the local links, instead of or on behalf of the distributed access routers or distributed GWs. In addition to this, the central controller handles distributed GW control.

The central controller particularly corresponds to CP functions of the standard SGW and PGW, and the distributed GW particularly corresponds to UP functions of the standard SGW and PGW. Regardless, as such, the central controller may contain full S/PGW functionality (including CP and UP portions), which may be particularly effective as a backup solution and/or for other purposes such as lawful interception … ….

It is noted that the central controller provides routing protocol functionality towards neighboring networks (e.g. OSPF, BGP). In addition, the central controller can interwork with the AAA server and/or the DHCP server for IP address management purposes. Still further, the central controller provides the functionality of the first hop routers in the network independent of how the traffic is routed and at what point/distributed GW it is switched to other (proprietary/foreign) networks/internet.

As shown in fig. 7-9, similar to fig. 4 above, a first (e.g., GTP) tunnel is established between the distributed GW and the access network/node, and a second (e.g., GTP) tunnel is established between the distributed GW and the central controller, except for the control interface. According to an exemplary embodiment of the present invention, the interface link (including the tunnel and control interface) between the central controller and the distributed GWs may operate as an S11+ interface.

Although the tunnels are exemplarily depicted as GTP tunnels in fig. 7 to 9, it is noted that any tunneling protocol may be used in this regard. However, it is preferred that the same tunneling protocol be used for both tunnels.

In general, a protocol for two tunnels according to an exemplary embodiment of the present invention may be used as a protocol for centralized IP address management (instead of AAA and/or DHCP protocol application in a distributed GW).

Fig. 7 shows a schematic diagram of a first example of a 3 GPP-based network architecture for internet access according to an exemplary embodiment of the present invention. The exemplary network architecture of fig. 7 illustrates a user/host specific GTP tunnel with S1-U and S11+ interfaces, where the central controller has no MME functionality.

As shown in fig. 7, the centralized controller may be operable at or through an entity to which a Mobility Management Entity (MME) and at least one distributed GW, such as at least one S/PGW, are connected. Thus, the central controller terminates the relevant GW signaling with the MME (i.e., mobility controller) and thus interworks with the MME.

That is, the central S/PGW control according to an exemplary embodiment of the present invention may be independent.

Fig. 8 shows a schematic diagram of a second example of a 3 GPP-based network architecture for internet access according to an exemplary embodiment of the present invention. The exemplary network architecture of fig. 8 illustrates a user/host specific GTP tunnel with S1-U and S11+ interfaces, where the central controller has MME functionality.

As shown in fig. 8, the centralized controller may be operable at or through a Mobility Management Entity (MME). Thus, the central controller itself or the entity implementing the central controller also comprises mobility controller functionality.

That is, the central S/PGW control according to the exemplary embodiments of the present invention may be combined with MME functions/entities.

Fig. 9 shows a schematic diagram of a third example of a 3 GPP-based network architecture for internet access according to an exemplary embodiment of the present invention. The exemplary network architecture of fig. 9 illustrates a user/host specific GTP tunnel with S1-U and S11+ interfaces, with a combination of a distributed GW and OpenFlow switches and a central controller and OpenFlow controller.

As shown in fig. 9, the centralized controller may be operable at or by an openflow (of) control entity or an entity comprising an openflow (of) control entity. Thus, the central controller itself or the entity implementing the central controller also comprises OpenFlow control functionality. Additionally, any distributed GW includes an openflow (of) switch that constitutes a corresponding openflow (of) message tunnel with an openflow (of) control entity at the central controller.

In the exemplary network architecture OF fig. 9, the OF message tunnel and the S11+ interface (including the tunnel and its control interface) are illustrated as separate connections. Alternatively, it is also feasible that an OF message tunnel is used to carry S11+ control messages to the distributed GW. In this case, the OF message tunnel may additionally serve as a control interface OF S11+, and the S11+ interface may include only its tunnel.

That is, the central S/PGW control according to the exemplary embodiments of the present invention may be combined with the OpenFlow control function/entity.

In other words, central IP address management/assignment may be combined with OpenFlow control of the network, which is also centralized. Thus, the OpenFlow controller may be part of a central controller, and the distributed GW may also contain OpenFlow controlled switches, where such functionality of flow routing may be used for traffic checking and splitting functions at the distributed GW. This is because the traffic check according to the exemplary embodiment OF the present invention can be implemented by the OF switch on the basis OF the packet header information.

It is noted that the central controller would also be operable at or through an entity comprising MME functionality and OpenFlow control functionality. That is, even a combination of concepts underlying the network architecture according to fig. 8 and 9 above is feasible. That is, the central S/PGW control according to the exemplary embodiments of the present invention may be combined with both MME functions/entities and OpenFlow control functions/entities.

Any of the network architectures according to fig. 8, 9 and the combination of fig. 8 and 9 may advantageously avoid the introduction of additional network elements in the overall system architecture compared to the network architecture according to fig. 7.

In view of the above, exemplary embodiments of the present invention provide centralized IP address management including IP address assignment for distributed gateways.

According to an exemplary embodiment of the present invention, the functionality of IP address management including IP address assignment in a network architecture with distributed gateways (or access routers) to connected hosts may be improved in terms of reduced network management efforts. In addition, such centralized IP address management provides benefits in terms of flexibility, e.g., in terms of smooth IP address changes, as well as accounting for relocation and/or potential changes in GW distribution scenarios and/or overall architecture, thereby also supporting efficiencies in terms of route optimization, load balancing, etc.

According to an exemplary embodiment of the present invention, the functionality of managing/assigning IP addresses to connected devices by distributed gateways or access routers may be centralized in a central controller while avoiding forced routing of all user traffic to the central controller. Thus, an "IP control layer packet" or the like that can facilitate IP address management/assignment is enabled to travel through the central controller, but avoids standard user IP traffic having to go to a centralized site as much as possible.

As a result thereof, the distributed switch/GW may be assigned to terminate (e.g., 3GPP specific) tunneling for maximum route optimization, e.g., for local traffic (such as access to local caches, IMS UP traffic, etc.). Meanwhile, an operator may assign all management interfaces required for IP address management to only one central controller (router/GW), which represents a distributed router/GW in a network from a centralized network perspective. Such centralization may also provide the benefit of more efficient hardware utilization of centralized network elements (e.g., may operate in a cloud computing environment). In this regard, it is effectively utilized that the control plane has a better overall network view and based on this information it can provide more network-wide (network-wide) optimal GW allocation and IP address management.

In particular, in addition to the aforementioned benefits resulting from the distribution of (internet) gateways, such as more direct/optimal routing, the following benefits may be achieved. That is, regardless of centralized IP address management, user plane processing may be maintained as decentralized (or may be even more distributed), thereby ensuring efficient routing.

First, the centralization of network management and control functions can be enhanced. Thereby, both the operating costs and capital expenditure of the overall system may be reduced. In this regard, the split between CP and UP control functionality between the central controller and the distributed GW is particularly effective. Such centralization is particularly beneficial for network architectures with a large number of other network functions/nodes, such as in the case of the distributed GW employed herein.

Second, virtualization technologies in network nodes and devices, such as virtual machines, cloud computing, can be enhanced. Thus, the utilization level of installed hardware may be increased and a centralized trend/effectiveness may be supported.

Third, network virtualization and programmable networks may be implemented. Thereby, cost-efficiency of future networks, e.g. due to network sharing, may be achieved. This is particularly effective when using OpenFlow based solutions, since the OpenFlow protocol is designed to standardize the separation of control and user plane functions in transport networks. Thus, further cost savings may be achieved, as network nodes for routing and switching may become less expensive, as they provide simplified functionality, and/or the control plane may be centralized. Such control plane centralization in turn allows for less expensive network management for the operator and decision making using information of the entire network view. The control plane of the transport network may cooperate or may be combined with (mobile) network control functions, which allows further optimization of resource usage.

The above described processes and functions may be implemented by respective functional elements, processors, etc., as described below.

Although in the foregoing exemplary embodiments of the present invention are mainly described with reference to methods, procedures and functions, the corresponding exemplary embodiments of the present invention also cover respective apparatuses, network nodes and systems, including both software and/or hardware thereof.

A respective exemplary embodiment of the invention is described below with reference to fig. 10, while for the sake of brevity reference is made to a detailed description of respective corresponding schemes, methods and functionalities, principles and operations according to fig. 4 to 9.

In fig. 10 below, the solid line boxes are basically configured to perform the respective operations as described above. The solid line blocks are generally configured to perform the methods and operations, respectively, described above. With respect to fig. 10, it is noted that the various blocks are intended to illustrate corresponding functional blocks that implement corresponding functions, procedures, or processes, respectively. Such functional blocks do not depend on the implementation, but can be implemented by means of any kind of hardware or software, respectively. The lines and arrows interconnecting the various blocks are intended to illustrate the operative coupling there between, which may be a physical and/or logical coupling, which is not implementation dependent (e.g., wired or wireless) on the one hand and may also include any number of intermediate functional entities not shown on the other hand. The direction of the arrows is intended to illustrate the direction in which certain operations are performed and/or the direction in which certain data is transferred.

Additionally, in fig. 10, only those functional blocks are illustrated that relate to any of the methods, processes, and functions described above. A person skilled in the art will recognize the presence of any other conventional functional blocks required for operation of a corresponding structural arrangement, such as for example a power supply, a central processing unit, a corresponding memory, etc. Among other things, a memory is provided for storing programs or program instructions for controlling the various functional entities to operate as described herein.

Fig. 10 shows a schematic diagram of an exemplary device according to an exemplary embodiment of the present invention.

In view of the foregoing, the devices 10 and 20 so illustrated are suitable for use in practicing the exemplary embodiments of the present invention, as described herein.

The apparatus 10 thus illustrated may represent (part of) a central controller and may be configured to perform processes and/or exhibit functionality as described in connection with any of fig. 4 to 9. The apparatus 20 as illustrated may represent (part of) a gateway or access router entity and may be configured to perform the procedures and/or expose the functionality as described in connection with any of fig. 4 to 9.

Any of the apparatuses 10 and 20 thus illustrated, as well as their architectural relationships and/or system-related interrelationships, may be configured as depicted in any of fig. 4 and 7 through 9. The combination of the devices 10 and 20 may constitute a logical gateway entity according to an exemplary embodiment of the present invention.

As indicated in fig. 10, according to an exemplary embodiment of the present invention, each of the devices 10/20 includes a processor 11/21, a memory 12/22, and an interface 13/23, which are connected by a bus 14/24 or the like, and the devices may be connected via links 30, respectively.

Processor 11/21 and/or interface 13/23 may also include a wire interface or the like to facilitate communication over a (hardwired or wireless) link, respectively. Interface 13/23 may include suitable transceiver communication means for (hardwired or wireless) communication with the linked or connected device(s), respectively. The interface 13/23 is generally configured to communicate with at least one other device, i.e., an interface thereof.

The memory 12/22 may store respective programs employed to include program instructions or computer program code that, when executed by respective processors, enable the respective electronic devices or apparatus to operate in accordance with exemplary embodiments of the present invention.

In general, the respective devices/apparatuses (and/or portions thereof) may represent means for performing the respective operations and/or exhibiting the respective functionalities, and/or the respective devices (and/or portions thereof) may have functions for performing the respective operations and/or exhibiting the respective functionalities.

When it is stated in the following description that the processor (or some other means) is configured to perform a certain function, this is to be interpreted as equivalent to the description: it is stated that a (i.e. at least one) processor or corresponding circuitry, potentially cooperating with computer program code stored in a memory of the respective apparatus, is configured to cause the apparatus to at least perform the functions as mentioned thus far. Also, such functions are to be construed as being equivalently implementable by specifically configured circuits or means for performing the respective functions (i.e., the expression "a processor configured [ to cause a device ] to perform xxx" is to be interpreted to be equivalent to an expression such as "means for xxx").

In its most basic form, according to an exemplary embodiment of the invention, the apparatus 10 or its processor 11 is configured to perform: the method comprises managing at the centralized controller entity IP addresses for hosts linked with the plurality of distributed gateway entities via a first host-specific tunnel, and controlling the plurality of distributed gateway entities in accordance with internet protocol address management from the centralized controller entity via a second host-specific tunnel on the basis of the managed IP addresses for the hosts.

Thus, in other words, the apparatus 10 may comprise respective means for managing IP addresses and means for controlling one or more distributed gateway entities.

As outlined above, in various forms, the apparatus 10 may comprise one or more respective functionalities or means for: controlling a plurality of distributed gateway entities according to a distributed gateway control, receiving an IP layer control message, utilizing the IP layer control message in IP address management, establishing a second user specific tunnel, setting an IP address, signaling a parameter indicating an application of IP address management, triggering a context establishment, and/or providing a first hop router function for providing internet connectivity to a host.

In its most basic form, according to an exemplary embodiment of the invention, the apparatus 20 or its processor 21 is configured to perform: providing a distributed gateway function for hosts linked via a first host-specific tunnel, acquiring control for IP address management of the hosts from a centralized controller entity via a second host-specific tunnel, and supervising IP address management for the hosts via the first host-specific tunnel on the basis of the acquired control for IP address management of the hosts.

Thus, in other words, the apparatus 20 may comprise respective means for providing distributed gateway functionality, means for obtaining control of IP address management and means for supervising IP address management for hosts.

As outlined above, in various forms, the apparatus 20 may comprise one or more respective functionalities or means for: obtaining distributed gateway control and controlling traffic of a host on the basis of the obtained distributed gateway control, checking traffic of the host, separating the checked IP layer control messages from the traffic and relaying the separated IP layer control messages to a centralized controller, establishing a first host-specific tunnel and/or a second host-specific tunnel, receiving parameters indicating an application of IP address management at the centralized controller entity, performing context establishment, and/or providing a user plane routing function for routing host traffic.

For further details regarding the operability/functionality of the respective devices, reference is made accordingly to the above description in connection with any of fig. 4 to 9.

According to an exemplary embodiment of the invention, the processor 11/21, the memory 12/22, and the interface 13/23 may be implemented as separate modules, chips, chipsets, circuits, etc., or one or more of them may be respectively implemented as a common module, chip, chipset, circuit, etc.

According to an exemplary embodiment of the invention, the system may comprise any conceivable combination of the thus depicted apparatus/devices and other network elements configured to cooperate as described above.

In general, it is noted that the respective functional blocks or elements according to the above-described aspects may be implemented by any known means, in hardware and/or software, respectively, if they are only adapted to perform the described functions of the respective parts. The mentioned method steps may be implemented in separate functional blocks or by separate devices or one or more method steps may be implemented in a single functional block or by a single device.

In general, any method steps are suitable to be implemented as software or by hardware without changing the idea of the invention. Such software may be independent of the software code and may be specified using any known or future developed programming language, such as, for example, Java, C + +, C, and assembler, as long as the functionality defined by the method steps is retained. Such hardware may be independent of the type of hardware and may be implemented using any known or future developed hardware technology or any mixture of these, such as MOS (metal oxide semiconductor), CMOS (complementary MOS), BiMOS (bipolar MOS), BiCMOS (bipolar CMOS), ECL (emitter coupled logic), TTL (transistor-transistor logic), etc., using, for example, ASIC (application specific IC (integrated circuit)) components, FPGA (field programmable gate array) components, CPLD (complex programmable logic device) components or DSP (digital signal processor) components. The apparatus/device may be represented by a semiconductor chip, a chip set, or a (hardware) module including such a chip or chip set; however, this does not exclude the possibility of: i.e. instead of a hardware implementation, the functionality of the device/apparatus or module is implemented as software in a (software) module, such as a computer program or a computer program product, comprising executable software code portions for executing/running on a processor. The apparatus may be considered as an apparatus/device or as an assembly of more than one apparatus/device, e.g. whether functionally cooperating with each other or functionally independent of each other but in the same apparatus housing.

The apparatus and/or the means or parts thereof may be implemented as separate devices, but this does not exclude that they may be implemented in a distributed manner throughout the system, as long as the functionality of the devices is preserved. Such and similar principles are to be considered known to those skilled in the art.

Software in the sense of the present description includes both software code itself, including code means or portions or a computer program product for performing the respective functions, as well as software (or a computer program product) embodied on a tangible medium, such as a computer readable (storage) medium having stored thereon a respective data structure or code means/portions, or embodied in a signal or in a chip, potentially during processing thereof.

The invention also covers any conceivable combination of method steps and operations described above, as well as any conceivable combination of nodes, devices, modules or elements described above, as long as the above-described concepts of method and structural arrangement are applicable.

In view of the above, measures are provided for centralized IP address management for distributed gateways. Such measures exemplarily include: the method comprises managing at the centralized controller entity IP addresses for hosts linked with the plurality of distributed gateway entities via a first host-specific tunnel, and controlling the plurality of distributed gateway entities in accordance with internet protocol address management from the centralized controller entity via a second host-specific tunnel on the basis of the managed internet protocol addresses for the hosts. Thus, control plane and user plane functions may be separated between a centralized controller entity and a plurality of distributed gateway entities.

The measures according to exemplary embodiments of the present invention may be applied in any kind of network environment, such as e.g. for a fixed communication system e.g. according to any relevant IEEE/IETF standard and/or a mobile communication system e.g. according to any relevant standard, such as e.g. 3GPP and/or 3GPP2, e.g. the UMTS standard and/or the HSPA standard and/or the LTE standard (including LTE-advanced and its evolution) and/or the WCDMA standard.

Although the invention is described above with reference to an example according to the accompanying drawings, it is to be understood that the invention is not limited thereto. Rather, it will be apparent to those skilled in the art that the present invention may be modified in many ways without departing from the scope of the inventive concept as disclosed herein.

List of acronyms and abbreviations

3GPP third generation partnership project

AAA authentication authorization and accounting

BRAS broadband remote access server

BGP border gateway protocol

BS base station

CDN content delivery network

CP control plane

DHCP dynamic host configuration protocol

eNB evolution Node B (E-UTRAN base station)

EPC evolved packet core (in EPS)

EPS evolution packet system (i.e. LTE RAN and EPC)

GGSN GPRS support node

GPRS general packet radio service

GTP GPRS tunneling protocol

GW gateway

Institute of IEEE (institute of Electrical and electronics Engineers)

IETF Internet engineering task force

IMSI International Mobile subscriber identity

IP internet protocol

LTE Long term evolution

MME mobility management entity

NAS non-Access stratum (i.e. Signaling between MME and UE)

OF OpenFlow

OSPF open shortest path first

PDN packet data network

PGW PDN GW

RAN radio access network

SGW serving GW

UE user equipment

UP user plane

UMTS universal mobile telecommunications system

UTRAN Universal terrestrial radio access network

WCDMA wideband code division multiple access

Claims (47)

1. A method at a centralized controller entity for centralized IP address management for distributed gateways, comprising

Managing control plane functions on behalf of a distributed gateway entity managing user plane functions, and internet protocol addresses of hosts linked to the distributed gateway entity, comprising:

receiving from the distributed gateway entity an Internet protocol layer control message of traffic from the host linked to the distributed gateway entity, an

Allocating an Internet protocol address of the host using the received Internet protocol layer control message.

2. The method of claim 1, further comprising

Controlling the distributed gateway entity in accordance with distributed gateway control from the centralized controller entity via a control interface.

3. The method of claim 1 or 2, further comprising

Receiving Internet protocol layer control messages for traffic from the host from the distributed gateway entity via a host-specific tunnel.

4. The method of claim 3, wherein

One or more of the internet protocol layer control messages comprise neighbor discovery protocol messages and/or dynamic host configuration protocol messages.

5. The method of any of claims 2 to 3, further comprising

Establishing a host-specific tunnel to the distributed gateway entity in the context of session establishment via a control interface, and/or

Setting an internet protocol address of the centralized controller entity for establishing the host-specific tunnel, and/or

Signalling to the distributed gateway entity a parameter indicating an application of internet protocol address management at the centralized controller entity, and/or

Triggering a context establishment at the distributed gateway entity.

6. The method of any of claims 1-2, further comprising

A first hop router function is provided for providing internet connectivity for the host.

7. The method of any of claims 2 to 3, further comprising at least one of:

interworks with at least one of a dynamic host configuration entity and an authentication, authorization and accounting entity,

interworking with mobility management entities, and

the host-specific tunnel is operable in accordance with the GPRS tunneling protocol.

8. The method of any one of claims 1 to 2, wherein

The centralized controller entity is operable at or by an entity connecting the mobility management entity with at least one of the serving and packet data network gateway entities, or

The centralized controller may be operable at or by the mobility management entity, or

The centralized controller is operable at or by an OpenFlow control entity or an entity comprising an OpenFlow control entity.

9. A method implemented by a distributed gateway entity for centralized IP address management for a distributed gateway, comprising

Managing user plane functions for hosts linked with the distributed gateway entity,

sending an Internet protocol layer control message of traffic from the host linked to the distributed gateway entity to a centralized controller entity managing control plane functions on behalf of the distributed gateway entity, and

supervising the centralized controller entity with the received Internet protocol layer control message to allocate an Internet protocol address of the host.

10. The method of claim 9, further comprising

Obtaining distributed gateway control from the centralized controller entity via a control interface, an

Controlling traffic of the host via the first host-specific tunnel on the basis of the acquired distributed gateway control.

11. The method of claim 10, further comprising

Checking traffic of said host on a first host-specific tunnel, an

Separating the examined internet protocol layer control messages from traffic of the host and relaying the separated internet protocol layer control messages to the centralized controller entity via a second host-specific tunnel.

12. The method of claim 11, wherein

One or more of the internet protocol layer control messages include neighbor discovery messages and/or dynamic host configuration messages.

13. The method of any of claims 10 to 11, further comprising

Establishing a first host-specific tunnel between the distributed gateway entity and the host in the context of session establishment, and/or

Establishing a second host-specific tunnel between the distributed gateway entity and the centralized controller entity in the context of session establishment,

receiving, from the centralized controller entity, a parameter indicating an application of internet protocol address management at the centralized controller entity, and/or

The context establishment is performed when triggered by the centralized controller.

14. The method of any of claims 9 to 10, further comprising

User plane routing functions are provided for routing traffic of the host.

15. The method of any one of claims 10 to 11, wherein

The first and second host-specific tunnels are operable in accordance with a GPRS tunneling protocol.

16. A centralized controller entity for managing control plane functions on behalf of a distributed gateway entity managing user plane functions, and internet protocol addresses of hosts linked to said distributed gateway entity, said centralized controller entity comprising

An interface configured to communicate with the distributed gateway entity,

a memory configured to store computer program code, an

A processor configured to cause the centralized controller entity to perform:

receiving from the distributed gateway entity an Internet protocol layer control message of traffic from a host linked to the distributed gateway entity, an

Allocating an Internet protocol address of the host using the received Internet protocol layer control message.

17. The centralized controller entity of claim 16, wherein processor is further configured to cause the centralized controller entity to perform:

controlling the distributed gateway entity in accordance with distributed gateway control from the centralized controller entity via a control interface.

18. The centralized controller entity of claim 16 or 17, wherein the processor is further configured to cause the centralized controller entity to perform:

receiving Internet protocol layer control messages for traffic from the host from the distributed gateway entity via a host-specific tunnel.

19. The centralized controller entity of claim 18, wherein

One or more of the internet protocol layer control messages include neighbor discovery messages and dynamic host configuration messages.

20. The centralized controller entity of any of claims 17-18, wherein processor is further configured to cause the centralized controller entity to perform:

establishing a host-specific tunnel to the distributed gateway entity in the context of session establishment via a control interface, and/or

Setting an internet protocol address of the centralized controller entity for establishing a host-specific tunnel, and/or

Signalling to the distributed gateway entity a parameter indicating an application of internet protocol address management at the centralized controller entity, and/or

Triggering a context establishment at the distributed gateway entity.

21. The centralized controller entity of any of claims 16-17, wherein processor is further configured to cause the centralized controller entity to perform:

a first hop router function is provided for providing internet connectivity for the host.

22. The centralized controller entity of any of claims 17-18, wherein processor is further configured to cause the centralized controller entity to perform:

interworked with at least one of a dynamic host configuration entity and an authentication, authorization and accounting entity, and/or

Interworking with mobility management entities, and/or

The host-specific tunnel is operable in accordance with the GPRS tunneling protocol.

23. The centralized controller entity of any of claims 16-17, wherein

The centralized controller entity may be operable at or by an entity connecting the mobility management entity with at least one of the serving and/or packet data network gateway entities, or

The centralized controller may be operable at or by the mobility management entity, or

The centralized controller is operable at or by an OpenFlow control entity or an entity comprising an OpenFlow control entity.

24. The centralized controller entity of any of claims 16-17, wherein

The centralized controller entity may be operable as or at a central controller, and/or

The centralized controller entity may operate as a packet data network gateway entity, and/or

The centralized controller entity comprises at least one control plane function of a serving and/or packet data network gateway entity.

25. A distributed gateway entity for centralized IP address management, comprising

An interface configured to communicate with at least one device,

a memory configured to store computer program code, an

A processor configured to cause the distributed gateway entity to:

managing user plane functions for hosts linked with the distributed gateway entity,

sending an Internet protocol layer control message of traffic from the host linked to the distributed gateway entity to a centralized controller entity managing control plane functions on behalf of the distributed gateway entity, and

supervising the centralized controller entity with the received Internet protocol layer control message to allocate an Internet protocol address of the host.

26. The distributed gateway entity of claim 25, wherein processor is further configured to cause the distributed gateway entity to perform:

obtaining distributed gateway control from the centralized controller entity via a control interface, an

Controlling traffic of the host via the first host-specific tunnel on the basis of the acquired distributed gateway control.

27. The distributed gateway entity of claim 25 or 26, wherein processor is further configured to cause the distributed gateway entity to perform:

checking traffic of said host on a first host-specific tunnel, an

Separating the examined internet protocol layer control messages from traffic of the host and relaying the separated internet protocol layer control messages to the centralized controller entity via a second host-specific tunnel.

28. The distributed gateway entity of claim 27, wherein

One or more of the internet protocol layer control messages include neighbor discovery messages and/or dynamic host configuration messages.

29. The distributed gateway entity of any of claims 26 to 27, wherein processor is further configured to cause the distributed gateway entity to perform:

establishing a first host-specific tunnel between the distributed gateway entity and the host in the context of session establishment, and/or

Establishing a second host-specific tunnel between the distributed gateway entity and the centralized controller entity in the context of session establishment, and/or

Receiving, from the centralized controller entity, a parameter indicating an application of internet protocol address management at the centralized controller entity, and/or

Performing context establishment upon triggering by the centralized controller entity.

30. The distributed gateway entity of any of claims 25 to 26, wherein processor is further configured to cause the distributed gateway entity to perform:

user plane routing functions are provided for routing traffic of the host.

31. The distributed gateway entity of any of claims 26 to 27, wherein

The first and second host-specific tunnels are operable in accordance with a GPRS tunneling protocol.

32. The distributed gateway entity of any of claims 25 to 26, wherein

The distributed gateway entity may be operable as or at a distributed gateway entity, and/or

The distributed gateway entity may operate as a serving gateway entity, and/or

The distributed gateway entity comprises at least one user plane function of a serving and/or packet data network gateway entity.

33. A centralized controller entity for centralized IP address management of distributed gateways, comprising

Apparatus for managing control plane functions, and internet protocol addresses of hosts linked to said distributed gateway entity, on behalf of a distributed gateway entity managing user plane functions, comprising:

means for receiving from the distributed gateway entity an internet protocol layer control message of traffic from a host linked to the distributed gateway entity, an

Means for allocating an internet protocol address of the host using the received internet protocol layer control message.

34. The centralized controller entity of claim 33, further comprising

Means for controlling the distributed gateway entity in accordance with distributed gateway control from the centralized controller entity via a control interface.

35. The centralized controller entity of claim 33 or 34, further comprising

Means for receiving Internet protocol layer control messages for traffic from the host from the distributed gateway entity via a host-specific tunnel.

36. The centralized controller entity of claim 35, wherein

One or more of the internet protocol layer control messages comprise neighbor discovery protocol messages and/or dynamic host configuration protocol messages.

37. The centralized controller entity of any of claims 34-35, further comprising

Means for establishing a host-specific tunnel to the distributed gateway entity in the context of session establishment via a control interface, and/or

Means for setting an internet protocol address of the centralized controller entity for establishing the host-specific tunnel, and/or

Means for signalling to the distributed gateway entity a parameter indicating an application of internet protocol address management at the centralized controller entity, and/or

Means for triggering a context establishment at the distributed gateway entity.

38. The centralized controller entity of any of claims 33-34, further comprising

Means for providing a first hop router function for providing internet connectivity for the host.

39. The centralized controller entity of any of claims 34-35, further comprising at least one of:

means for interworking with a dynamic host configuration entity and at least one of an authentication, authorization and accounting entity, and/or

Means for interworking with mobility management entities, and/or

The host-specific tunnel is operable in accordance with the GPRS tunneling protocol.

40. The centralized controller entity of any of claims 33-34, wherein

The centralized controller entity may be operable at or by an entity connecting the mobility management entity with at least one of the serving and/or packet data network gateway entities, or

The centralized controller may be operable at or by the mobility management entity, or

The centralized controller is operable at or by an OpenFlow control entity or an entity comprising an OpenFlow control entity.

41. A centralized controller entity for centralized IP address management of distributed gateways, comprising

Means for managing user plane functions for hosts linked with the distributed gateway entity,

means for sending an internet protocol layer control message for traffic from said host linked to said distributed gateway entity to a centralized controller entity managing control plane functions on behalf of said distributed gateway entity, and

means for supervising the centralized controller entity with the received Internet protocol layer control message to allocate an Internet protocol address of the host.

42. The centralized controller entity of claim 41, further comprising

Means for obtaining distributed gateway control from the centralized controller entity via a control interface, an

Means for controlling traffic of the host via the first host-specific tunnel on the basis of the acquired distributed gateway control.

43. The centralized controller entity of claim 41 or 42, further comprising

Means for checking traffic of said host on a first host-specific tunnel, an

Means for separating the examined Internet protocol layer control messages from traffic of the host and relaying the separated Internet protocol layer control messages to the centralized controller entity via a second host-specific tunnel.

44. The centralized controller entity of claim 43, wherein

One or more of the internet protocol layer control messages include neighbor discovery messages and/or dynamic host configuration messages.

45. The centralized controller entity of any of claims 41-42, further comprising

Means for establishing a first host-specific tunnel between the distributed gateway entity and the host in the context of session establishment, and/or

Means for establishing a second host-specific tunnel between the distributed gateway entity and the centralized controller entity in the context of session establishment, and/or

Means for receiving from the centralized controller entity a parameter indicating an application of internet protocol address management at the centralized controller entity, and/or

Means for performing context establishment when triggered by a centralized controller.

46. The centralized controller entity of any of claims 41-42, further comprising

Means for providing user plane routing functionality for routing traffic of the host.

47. The centralized controller entity of any of claims 42-43, wherein

The first and second host-specific tunnels are operable in accordance with a GPRS tunneling protocol.