HK1100860B - A method and arrangement for transport network layer control signalling in utran supporting both atm and ip - Google Patents

Description

Method and apparatus for transport of network layer control signaling in UTRAN supporting ATM and IP

Title

Transport network control signaling

Technical Field

The present invention relates to a method and arrangement in a mobile telephone network. In particular, the present invention relates to a method and apparatus for Transmitting Network Layer (TNL) control signaling in a Universal mobile telephone System Terrestrial Radio Access Network (Universal mobile telephone System Terrestrial Radio Access Network UTRAN).

Background

The UMTS Terrestrial Radio Access Network (UMTS Terrestrial Radio Access Network utran) is a Radio Access Network (Radio Access Network RAN) of the third generation mobile Network specified by the 3GPP standardization organization. The general protocol model of the UTRAN interface is shown in fig. 2 a. The protocol model can be divided into two logically independent layers: radio Network Layer RNL (Radio Network Layer RNL) and Transport Network Layer (TNL), and is orthogonally divided into a user plane and a control plane, as described in 3GPP TS 25.401, 3GPP, TSG RAN: further described in the UTRAN general description.

According to fig. 1, the main parts of the UTMS are the core network 101, the UTRAN 102 and the user equipment (user equipment UE)107, also called mobile terminal. The interface between the core network 101 and the UTRAN 102 is referred to as the Iu interface 108, and the interface between the UTRAN 102 and the user equipment 107 is referred to as the Uu interface 111. The UTRAN 102 includes Radio Network Subsystems (Radio networks Subsystems RNS). The interface between the two RNSs is referred to as the Iur interface 109. The RNS includes an RNC 104 and one or more node bs 105 also referred to as base stations. The interface between RNC 104 and node B105 is referred to as Iub interface 110. The coverage area (i.e., cell) of the node B is indicated at 106.

As a general trend, the early versions of UTRAN are based on ATM, while the new versions of UTRAN are based on IP technology. Hybrid ATM and IP based networks are also possible. There is a significant difference between the two transport technologies in that ATM is connection-oriented and IP is the less-connected transport method.

In ATM-based UTRAN, the user data uses AAL2 and the TNL signaling uses AAL5 protocol. AAL2 and AAL5 Connections are transported in Virtual Connections (Virtual Connections VC) and Virtual Paths (Virtual Paths VP), both configured by management system or ATM signaling. For different types of user traffic different service classes are defined, such as Constant Bit Rate (CBR), Variable Bit Rate (VBR), Unspecified Bit Rate (UBR), which are characterized by different traffic parameters. The required Quality of Service (Quality of Service QoS) is ensured by a Call Admission control mechanism (CAC) running for each VP/VC.

IP will be introduced in future UTRAN releases and therefore migration paths from ATM to IP must be planned. Smooth migration from ATM to IP transport technologies in UTRAN requires that ATM and IP based network parts co-exist. Interoperability between ATM and IP network parts must be provided for the Iu, Iur, Iub interfaces as illustrated in fig. 1. If these nodes do not support ATM and IP technologies, then an Inter-working Unit IWU must operate between the ATM and IP network parts.

Currently available and basic solutions for the transport network control plane of AAL2/ATM networks are e.g. ITU-T recommendation q.2630.2: q.2630 signaling described in "AAL type 2 signaling protocol (Capability Set 2)". Q.2630 is used to establish AAL2 connections in an ATMUTRAN network, but q.2630 signalling is not suitable for configuring the ATM layer. In ATM UTRAN, permanent and semi-permanent VP and VCs are used, which are manually configured by a management system.

In IP networks, packets are routed by standard IP routing protocols, and IP-based transport protocols provide reliable or unreliable transport services to IP packet delivery. In order to provide QoS in IP networks, where different traffic types are transmitted within the same time period, two fundamentally different architectures have been developed: integrated Services (Integrated Services IntServ) and Differentiated Services (Differentiated Services DiffServ). In IntServ, resources in the router are provided to each traffic flow, whereas in DiffServ, traffic types are classified according to their Per-Hop characteristics (Per Hop behavviour PHB) and resources are typically provided Per PHB.

Resource Management in DiffServ RMD methods in L.Westberg et al, can be used for dynamic Resource Management in IP networks

"Resource Management in DiffServ Framework" (Internet Draft, Work in progress, 2001) is described; and "resource management in DiffServ (RMD) in l.westberg et al: a Functionality and Performance BehaviorOverview "(Protocols for High Speed Networks, 2002, Berlin) is described. In RMD, resource management is performed on two scales: each traffic reservation is made at the edge node and each traffic class reservation or measurement-based reservation is made at the edge node. The main advantages of RMD compared to IntServ-based reservation methods are scalability in the inner nodes and lightweight protocol implementation.

For TNL control in an IP-based UTRAN network, the IP-based TNL signaling protocol IP-ALCAP is used. IP-ALCAP conforms to 3GPP [3GPP TSG RAN WG 3: r3-021366 "A2 IP Signalling Protocol (q. ipalcap spec. draft)"; WO 03/019897A1 shows a solution for interworking between IP-ALCAP and Q.2630. QoS is ensured by over provisioning resources in IP routers or by using complex resource reservation schemes (e.g. using IntServ method in IP-ALCAP) that require a reservation state for each connection. The protocol stacks available in the TNL control plane and the user plane are shown in fig. 2a for the Iub interface.

The motivation for introducing IP transport into UTRAN is, for example, that it better supports mixed traffic types in narrow links, an increasing number of IP-based applications, and IP-based operation and maintenance. A further advantage is that IP is independent of the data link layer, highly deployed IP routers reduce their price, and dynamic update and auto-configuration capabilities of routing tables can be used.

Hybrid ATM and IP transport is also possible. In a typical hybrid ATM-IP network, a higher layer ran (hran) is IP based and a lower layer ran (lran) is ATM based, and an interworking unit (IWU) operates between the ATM and IP network portions. In the IWU, the q.aal2 and IP-ALCAP messages must be converted. See fig. 2 b.

Examples of the disadvantages of the above-described IP-ALCAP solution are listed below:

the standard IP routing protocol does not interoperate with IP-ALCAP. IP-ALCAP is based on per-hop bi-directional connection setup like q.2630, so routing is static. In case of link or node failure or in case of congestion in the link, the connection must be terminated and a new connection must be established between the RNC and the node B.

It is not appropriate to use IP-ALCAP for resource reservation in IP routers and Diffserv-based resource reservation schemes like RMD cannot be used. In addition, as in RSVP, resource management of IP-ALCAP soft-state may not be used.

The standard solution of the UTRAN based on ATM/AAL2 described above also has the following disadvantages:

to be able to dynamically establish an ATM VC, an ATM signaling protocol is required which is independent of the q.aal2 signaling used to establish the user connection. Since the VC configuration changes rarely, it is not worth implementing a separate signaling protocol for this purpose. Thus, ATM layers VC and VP are typically configured manually via a management system.

Mixed IP and ATM/AAL2 networks suffer from the following disadvantages:

in a hybrid ATM-IP network, two different protocols must be used to establish the AAL2 connection: q.aal2 in ATM section and IP-ALCAP in IP section. An interworking function for the TNL control plane is required between the ATM and IP parts.

In a hybrid ATM-IP network, two addressing structures are used, IP addressing in the IP part and ATM End System addressing (ATM End System addressing aesa) in the ATM part, which complicates addressing. In the RNC, addresses need to be translated between IP and ATM, and ATM and IP address tables must be maintained.

Migration from ATM to IP is only possible in large steps with significant instantaneous investment: in the IP part, both hardware and software for the control plane must be replaced. Future link layer technologies such as ethernet, MPLS, optical switching may require the implementation of new TNL signaling protocols.

Disclosure of Invention

It is therefore an object of the present invention to provide an improved transport network control signalling which overcomes the above disadvantages.

In one aspect of the present invention, there is provided a method for controlling a user plane of a UMTS terrestrial radio access network, UTRAN, comprising a first edge node connected to a second edge node via a transport network layer, by using transport network layer, TNL, signalling, the method comprising the steps of:

-establishing a radio link by using a node B application part between a first and a second edge node of said UTRAN, said method being characterized in that it further comprises the steps of:

transmitting RSVP-TE based TNL signaling messages between the first and second edge nodes for each TNL flow,

each TNL flow is identified by using RSVP-TE messages, where the objects SESSION and SENDER _ TEMPLATE comprise IP-based 5-tuple flow information, which is adapted to be used as TNL flow identity.

In another aspect of the present invention there is provided an apparatus for controlling the user plane of a UMTS terrestrial radio access network, UTRAN, comprising a first edge node connected to a second edge node via a transport network layer, by using transport network layer, TNL, signalling, said apparatus comprising means for establishing a radio link by using a node B application part between the first and second edge nodes of the UTRAN, characterised in that the apparatus comprises means for transmitting RSVP-TE based TNL signalling messages between the first and second edge nodes for each TNL flow,

means for identifying each TNL flow by using RSVP-TE messages, wherein the objects SESSION and SENDER _ TEMPLATE comprise IP-based 5-tuple flow information, which is adapted to be used as TNL flow identity.

The invention has the following advantages:

the invention may use standard IP based routing and management, which allows for more automatic configuration and more flexible fault handling. DiffServ-based resource reservation can be performed by using RSVP-TE extended with RMD objects.

The invention is also suitable for bi-directional signalling and soft reservation states can be used which results in simpler signalling and a more robust design.

The introduction of RSVP-TE based signaling shows a smaller migration step from ATM migration to IP. As a first migration step the control plane may be changed to IP based RSVP-TE, only requiring software updates in the RNC and node B. The user plane may then be changed to IP from HRAN. Future link layer technologies such as ethernet, MPLS, optical switching may also be more easily adapted to UTRAN. Thus, RSVP-TE based signaling solutions can be used to control AAL2/ATM TNL in UTRAN. The signaling solution according to the invention can also be used to control both mixed AAL2/ATM and IP based TNL in UTRAN, so that in mixed IP-ATM based UTRAN no inter-working functions in TNL are needed or only very light weight inter-working functions are needed.

The ATM and AAL2 layers may be controlled with one protocol, in contrast to prior art solutions where q.aal2 signaling is used to control the AAL2 layer and the ATM layer is configured using a management system.

Another advantage of the solution according to the invention is that a dynamic configuration of the ATM layer can be performed, whereas in prior art solutions with q.aal2 and management systems permanent VCs and VPs are used.

The IP, ATM and AAL2 layers may be controlled by one protocol. This feature reduces the required signalling and operational maintenance costs.

Since a standard IP based management system is used, IP addressing and DNS naming structures are used, which means ATM ASEA is not required.

In the AAL2/ATM part, the same AAL2 admission control can be used as in the case of q.aal2 signaling.

Drawings

For a more complete understanding of the present invention, reference is made to the following detailed description, taken in conjunction with the accompanying drawings, in which:

figure 1 schematically illustrates a UTRAN in which the present invention may be implemented.

Figure 2a schematically shows the logical partitioning of the UTRAN protocol model.

Figure 2b schematically shows the migration step from ATM to IP in UTRAN. HRAN is IP based and LRAN is AAL2/ATM based. The TNL control plane is IP-ALCAP and q.

Fig. 3a shows a signaling scheme in an IP based UTRAN according to an embodiment of the present invention.

Figure 3b shows a signaling scheme in a hybrid IP/ATM UTRAN according to an embodiment of the present invention.

Fig. 4a is a signaling scheme for unidirectional reservation according to an embodiment of the present invention.

Fig. 4b shows a signaling scheme for a two-pass PATH and RESV message for bidirectional reservation, in accordance with an embodiment of the present invention.

Fig. 5 is a table with objects sent in PATH and RESV messages.

Fig. 6 schematically illustrates a LABEL object with AAL2 labeled ranges and a subject LABEL REQUEST, in accordance with an embodiment of the present invention.

Fig. 7 is a flow chart of a method according to the invention.

Detailed Description

The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, like numbers refer to like elements.

The Transport Network Layer (TNL) signaling solution according to the present invention is suitable for implementation in a UMTS Terrestrial Radio Access Network (UTRAN) TNL. The UTRAN includes at least one RNC connected to at least one node B via TNL as described above. TNL signalling according to the invention is based on the standard IP resource reservation-traffic engineering protocol (RSVP-TE), which is an extension of RSVP for supporting label switched tunnels, described in r.braden et al: resource ReSerVation Protocol (RSVP), version 1 functional Specification, RFC 2205, 9 months 1997; and described in d.awdche: extensions to RSVP for LSPTunnels, RFC3209, month 12 of 2001. RSVP-TE signaling is performed per flow connection and standard RSVP-TE messages and objects are used.

One of the functions required for TNL signaling is flow identification. For each connection, the TNL signaling message must contain flow identification information. In accordance with the current RSVP-TE message, a standard SESSION object carries the IP address, UDP port number and protocol ID of the node B. SENDER _ TEMPLATE includes the RNC IP address and UDP port number. In this manner, SESSION and SENDER _ TEMPLATE are objects that contain IP-based 5-tuple flow information. In accordance with the invention, this identity is used in UTRAN for flow identification in TNL signalling. The SESSION and SENDER _ TEMPLATE information is handled by an edge node (such as node B or IWU) rather than in an interior node.

The present invention thus relates to a method and arrangement for controlling the user plane of a UMTS terrestrial radio access network, UTRAN, by using transport network layer, TNL, signalling, said UTRAM comprising a first edge node connected to a second edge node via a transport network layer, wherein a radio link is established by using a node B application part between the first and second edge nodes of said UTRAN, RSVP-TE based TNL signalling messages are transmitted between said first and second edge nodes for each TNL flow, and each TNL flow is identified by using RSVP-TE messages, wherein the objects SESSION and SENDER _ TEMPLATE comprise IP based 5-tuple flow information, said 5-tuple flow information being used as TNL flow identity.

In accordance with a first embodiment of the invention, the TNL signaling solution is adapted to be implemented in an IP based UTRAN. For each connection, an RSVP-TE tunnel is established and standard RSVP-TE objects and messages are used as described above. To implement bidirectional reservation, one tunnel is established for downstream user traffic and another tunnel is established for upstream user traffic.

In fig. 3a is shown a network model between an RNC and a node B in case of a full IP based network according to a first embodiment of the invention. The network model includes an RNC, a node B (also denoted as a base station), and an internal router. The terminology using the RMD principle refers to the RNC and the node B as edge nodes.

The solution according to the first embodiment of the invention can also be used in the case of a hybrid IP/ATM network, where the interworking unit (IWU) is adapted to operate between IP and ATM network parts. This scheme is shown in fig. 3 b. In this case, the IWU is an edge of the RMD domain.

Referring to fig. 3a and 3B, radio link connections are established by Node B Application Part (NBAP) signaling between an RNC and a Node B according to the prior art. The setup is started by sending a radio link setup request at the RNC. The request is answered by the node B in a radio link setup response message. In NBAP signaling, the IP address and UDP port number are exchanged as shown in fig. 3a and 3 b. Optionally, a DiffServ Code Point (DiffServ Code Point DSCP) may also be sent.

As shown in fig. 3a and 3b, bidirectional resource reservation is established by the TLN message, the two-pass PATH message and the two-pass RESV message. Two functions that the TNL signaling has to provide are flow definition and resource reservation.

Flow identification is performed as described above in accordance with the present invention. Also as described above, the PDR object contains a flow identity, which is a combination of source and destination edge node IP addresses and DSCP fields.

The message sequence for establishing a bidirectional connection is shown in fig. 3a and 3 b. In the RMD domain, the messages are routed upstream and downstream according to standard routing protocols. Unlike standard RSVP and RSVP-TE principles, per-hop routing state is not stored in routers in the RMD domain. According to the first embodiment, an RSVP-TE message configured to contain a standard RSVP-TE object and two objects (i.e., a PHR and a PDR) described further below is introduced to perform Resource reservation according to a Resource Management in DiffServ method. In order to provide QoS, resource reservation is required. In "Resource Management in DiffServ frame" by L.Westberg et al (Internet draft, Work in Progress, 2001) and "Resource Management in DiffServ (RMD) by L.Westberg et al: the PHR and PDR objects are defined in the RMD principles disclosed in A Functionality and Performance BehaviorOverview ″ (Protocols for high speed Networks, 2002, Berlin).

The resource reservation scheme of the first embodiment of the present invention is based on the RMD architecture. In RMD, only edge nodes (such as RNC and IWU, as in the hybrid IP and ATM/AAL2 network illustrated in fig. 3 b) use complex reservation methods and maintain the resource reservation state for each flow. In the interior nodes shown in fig. 3a and 3b, such as IP routers, it is only appropriate to use very simple resource reservation methods, such as summing resource units and to maintain only aggregated reservation states.

RSVP-TE messages are adapted to contain standard RSVP-TE objects and RMD specific objects: PHR and PDR objects. The RNC starts signaling by sending a PATH message to the node B. The PATH message includes a PDR object and a PHR object. The PHR contains simple reservation information such as bandwidth for the interior nodes and downstream direction. The PDR object contains the flow identity as described above and may also contain resource reservation information for upstream reservations. The PHR object is processed in each inner node passed through, and reservation is performed. The PDR objects sent by the RNC are only processed at the edge nodes, i.e. at the node B or IWU.

After processing the PATH message in the node B, the node B responds with a RESV message. In the RMD domain, the RESV message is routed according to standard routing protocols, while outside the RMD domain, the RESV message is subsequently sent to the PATH message in the reverse direction as in the case of RSVP. Different routing is used inside and outside the RMD domain. Within the RMD domain, standard IP routing such as OSPF or BGP is used. Outside the RMD domain, routing is done as in the case of RSVP: PATH installs the transport state in the router (stores the IP address and port number of the previous hop) and sends RESV to this address. In this way, the RESV follows the same route as the PATH in the opposite direction. If the upstream and downstream IP routes are different (IP routing is asymmetric), there is a difference between the methods used inside and outside the RMD domain. The edge node, i.e. node B in the case of full IP as shown in fig. 3a or IWU in the case of hybrid ATM/IP as shown in fig. 3B, inserts the PDR object into the RESV message. The PDR object contains reservation confirmation information.

The PATH message is also sent by the node B. The edge node (node B in the case of full IP or IWU in the case of hybrid ATM/IP) inserts PHR and PDR objects for resource reservation in the upstream direction. The PHR is handled in each inner node, while the PDR is handled only in the RNC. Resource reservation is performed in the same manner as in the downstream direction.

After receiving the PATH, the RNC sends back a RESV message to the node B. The RESV may be employed to send PDR objects containing reservation confirmation information to edge nodes in the RESV.

The reservation state in the DiffServ domain is a soft state that is refreshed periodically during the connection time. Resource refresh is performed in the RMD domain by sending PATH messages as described in RSVP-TE and RMD architectures. After a timeout period, resources that are not refreshed are removed.

The tear-down and fault handling operations follow the scheme of RMD and the message operations can be derived in the same way as in the basic operating case.

According to a second embodiment of the invention, the TNL signaling comprises an extension of RSVP-TE in the ATM/AAL2 domain to be used for UTRAN. That is, a single control protocol, i.e., IP and/or ATM/AAL2, may be used regardless of the transport technology. Thus, in a network using a hybrid AAL2/ATM and IP transport solution, no IWU is required in the TNL control plane between the ATM/AAL2 network and the IP network. However, the TNL signaling according to the second embodiment requires additional objects in addition to the current RSVP-TE and in addition to the TNL signaling according to the first embodiment of the invention. However these additional objects must be excluded from the IP domain to ensure proper operation. To enable the application of AAL2 admission control functions used in one version of UTRAN, the TNL signaling also includes objects that may use the existing RSVP-TE.

The TNL signaling according to the second embodiment is in the following way:

TNL signaling is adapted to control the ATM and AAL2 layers of the AAL2 switch. Thus, establishing a new AAL2 connection may begin creating or modifying an ATM VC.

Furthermore, TNL signaling may also be adapted to control only the AAL2 layer. The ATM layer of the AAL2 switch is semi-permanently configured by standard RSVP-TE or via a management system. This is denoted RSVP-te (atm) and is performed according to the prior art.

The model of UTRAN between RNC and node B and the basic unidirectional signaling operation is shown in fig. 4 a. In the network part between the RNC and the ALL2 switch shown in fig. 4a, the ATM network layer is semi-permanent, while the other part (between the AAL2 switch and the node B) is dynamically set up as required. This means that only the AAL2 layer is controlled by RSVP-TE signaling (ATM layer is controlled by, for example, a network management system) between the RNC and the AAL2 switch, while both AAL2 and ATM are controlled by RSVP-TE between AAL2SW and the node B. This is represented in fig. 4a and b by PATH (AAL2), PATH (ATM, AAL2), etc. This will be explained further in the next paragraph. In the semi-permanent part, CBR, VBR or UBR may be used⁺VC, and in the dynamic part UBR is considered⁺VC。

According to the prior art, the radio link connection is established by NBAP signaling between the RNC and the node B, as in the first embodiment of the invention.

According to the invention, RSVP-TE signaling is performed for each AAL2 connection. To distinguish protocol functions and protocol messages in different network parts, the protocol messages are denoted by RSVP-TE in the ATM/AAL2 part (semi-) permanently establishing the ATM VC (AAL2) and RSVP-TE in the ATM/AAL2 part (ATM, AAL2) dynamically establishing the ATM and AAL2 layers.

Considering the RSVP-TE function, in fig. 4a the RNC is the sender and the node B is the receiver. In standard RSVP-TE, resource reservation is performed by the receiver in the reverse direction. Since the RNC in the UTRAN has all flow identification and reservation information, all relevant information is actually signaled from the RNC. The node B acts as a proxy for reflecting the received information as necessary to comply with the current standard.

The three functions that need to be provided by ATM/AAL2 TNL signaling are (1) flow identification (2) AAL2/ATM layer configuration and (3) QoS provisioning.

Flow identification of control messages is performed as described above in accordance with the present invention.

To configure the ATM/AAL2 network part, CID, VPI/VCI values must be signaled between adjacent nodes along the path of the AAL2 connection. To this end, a LABEL _ REQEST (Standard RFC3209) with a range of ATM LABELs is sent to the next ATM/AAL2 switch, from which the ATM/AAL2 switch can select the LABEL to be used on a particular link. For the AAL2 configuration, a new class type must be defined, which is labeled AAL2_ LABEL _ REQUEST in accordance with the second embodiment of the present invention. AAL2 LABEL REQUEST is sent to the next AAL2 switch with a PATH message indicating the AAL2 LABEL range (i.e., CID range) from which the next hop AAL2 switch can select a single value. The form of this defined object is disclosed in fig. 6.

In the RESV message, the ATM and AAL2 marking request is answered by sending two LABEL objects with the RESV message: the ATM LABEL object contains the VPI and VCI, while the AAL2_ LABEL object contains the CID of the connection. The LABEL and AAL2_ LABEL objects are processed by the same node that initiated the LABEL _ REQUEST and AAL2_ LABEL _ REQUEST. The manner in which the above objects are used depends on whether the ATM layer is dynamically configured.

If the ATM layer is statically configured, the new connection must use the VC already present. Therefore, the AAL2 switch must select a VPI/VCI pair belonging to an existing VC with sufficient resources for the new AAL2 connection. If no VC has sufficient resources, e.g. no CID value available or insufficient free capacity, the call is blocked.

If both ATM and AAL2 are dynamically configured, then two scenarios are possible. If there are VCs that have been established with sufficient resources, this VC can be used, i.e., AAL2 switch selects its VP/VC identifier. Otherwise, a new VC should be established with the new AAL2 connection. That is, a new VPI/VCI is selected by the AAL2 switch. Note that the VCI, VPI or CID may be explicitly assigned by the sender if the range is limited to one value.

In the ATM/AAL2 network part, QoS is ensured by AAL2 CAC. One object of the second embodiment is to minimize new implementations in ATM/AAL2 nodes, e.g. to avoid developing new CAC algorithms. The AAL2CAC algorithm in one version of UTRAN, AAL2 switch has the following parameters: number of sources, link capacity, packet size, Transmission Time Interval (Transmission Time Interval TTI), activity factor, QoS class, delay and loss requirements, segment size, and priority. In the prior art, only the packet size, TTI, activity factor, QoS class and priority among these parameters are signaled by q.aal2. Other parameters are either configured (e.g., link capacity) or measured (e.g., number of sources).

It is assumed that the TNL signaling according to the second embodiment has to signal the same AAL2CAC parameters as q.aal2. This may be performed by filling in the DSCP field and token bucket descriptor appropriately.

The token bucket descriptor is signaled in the object SENDER _ TSPEC and the object FLOW _ SPEC. The object SENDER _ TSPEC is sent in a PATH message containing IntServ traffic descriptors of the user traffic. This traffic information is used in the receiver node of the FLOW to define the object FLOW SPEC, which is sent back with the RESV message. The actual reservation is based on the traffic parameters specified in the FLOW _ SPEC object. Since multicast is not supported, FLOW _ SPEC is actually exactly the same as SENDER _ TSPEC.

The dclas object contains the DSCP of the stream. It is assumed that DSCP is exchanged in NBAP signalling, which means that the node B can put attribute values in the RESV message. FLOW _ SPEC and DCLASS are considered to be used by AAL2CAC to make admission control decisions. The CAC parameters signaled in the FLOW SPEC object are packet size (bucket size) and TTI (bucket size/token ratio). The priority and QoS class are signaled in the dclas object. Thus, the only remaining CAC parameter signaled by q.aal2 that has not yet been mapped to RSVP-TE is the activity factor. The activity factor cannot be obtained from the standard IntServ token bucket parameters. This may be performed in three ways in accordance with embodiments of the present invention. First, activity factor values are configured in the AAL2/ATM nodes and classified using DSCP and other traffic descriptors. Second, signaling in an unused field in TSPEC and FLOW _ SPEC, and finally defining new fields and objects to signal the value of the activity factor. However, the activity factor may also be obtained in another way, which is obvious to a person skilled in the art.

Examples for successful establishment of a bidirectional connection are disclosed below. Unsuccessful setup, refresh, tear down operations are also based on standard RSVP-TE features and can also be derived from the following examples. When asymmetric routing is assumed, this means that the routes of Uplink (UL) and Downlink (DL) traffic may be different. This requires a two-pass PATH message flow and a two-pass RESV message flow, as shown in fig. 4 b. The RESV message for the DL flow may be transmitted simultaneously with the PATH message for the UL flow. Note that this bidirectional reservation consists of two independent unidirectional reservations. Thus, the flow identifiers for the two directions are not the same, and the assigned labels for the two directions on the same link may also be different.

In the table of fig. 5, the most important objects sent with PATH and RESV messages are described. The table also indicates which nodes read and which write to the listed objects. In the case of UTRAN, one problem for the node B is to fill in the objects for uplink reservation (i.e. SENDER _ template, SESSION, SENDER _ TSPEC). Accordingly, the node B must fill in the objects SENDER _ TEMPLATE and SESSION for the PATH message belonging to the uplink reservation. The solution according to the second embodiment of the invention is to copy the IP address and port from SENDER TEMPLATE of path (dl) to SESSION object of path (ul) and to copy the IP address and port from SESSION object of path (dl) to SENDER TEMPLATE of path (ul).

Other objects related to uplink reservation are the SENDER _ TSPEC object. In accordance with normal operation, the receiver distributes the content of the FLOW _ SPEC object in accordance with the information received in the object SENDER _ TSPEC. For uplink reservation, the RNC is configured to fill in the FLOW _ SPEC object according to local information, while ignoring the SENDER _ TSPEC object sent by the node B. The LABEL _ REQUEST, AAL2_ LABEL _ REQUEST, LABEL and AAL2_ LABEL objects are used in the same way as in the case of one-way reservation.

A subject LABEL and a subject LABEL REQUEST having AAL2 LABEL ranges are defined according to a second embodiment of the present invention. As per the protocol described in RFC3209 [ d.awdche: the LABEL object with ATM tag ranges and the LABEL _ REQUEST object described in Extensionsto RSVP for LSP Tunnels, RFC3209, 12.2001 ] are defined in a similar manner. As shown in fig. 6, the lower significant 8 bits contain the channel identification (channel identification CID) value.

The proposed TNL signaling may also be used in a hybrid ATM-IP network according to a third embodiment of the present invention, where the HRAN is IP based and the LRAN is ATM based. An interworking unit (IWU) operates between the ATM and IP network parts, see fig. 2 b. In the user plane, it is an advantage of the present invention that the IWU converts IP packets to ATM packets, whereas the IWU is not required for the control plane.

The method according to the invention is illustrated by the flow chart in fig. 7. Thus, there is provided a method for controlling a user plane of a UMTS terrestrial radio access network, UTRAN, comprising a first edge node connected to a second edge node via a transport network layer, by using transport network layer, TNL, signalling, the method comprising the steps of:

701. transmitting RSVP-TE based TNL signaling messages between the first and second edge nodes for each TNL flow,

702. each TNL flow is identified using RSVP-TE messages, where the objects SESSION and SENDER _ TEMPLATE comprise IP-based 5-tuple flow information, which is adapted to be used as TNL flow identity.

Furthermore, the device according to the invention comprises means for performing the method of the invention and the preferred embodiments. The apparatus may be implemented by software and/or hardware means in the RNC, node B and/or IWU.

In the drawings and specification, there have been disclosed typical preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being set forth in the following claims.

Claims (38)

1. A method for controlling a user plane of a UMTS terrestrial radio access network, UTRAN, comprising a first edge node connected to a second edge node via a transport network layer, by using transport network layer, TNL, signalling, the method comprising the steps of:

-establishing a radio link by using a node B application part between a first and a second edge node of said UTRAN, said method being characterized in that it further comprises the steps of:

-transmitting (701) RSVP-TE based TNL signalling messages between the first and second edge nodes for each TNL flow,

each TNL flow is identified (702) by using RSVP-TE messages, wherein the objects SESSION and SENDER _ TEMPLATE comprise IP-based 5-tuple flow information, which is adapted to be used as TNL flow identity.

2. The method of claim 1, wherein the method further comprises the steps of:

an RSVP-TE tunnel is established for each connection direction between the first edge node and the second edge node.

3. The method according to any of claims 1-2, wherein the method further comprises the step of:

the TNL signaling is started by sending a PATH message comprising at least reservation information and a TNL flow identity, the reservation information being for an interior node.

4. The method of claim 3, wherein the reservation information is bandwidth.

5. The method of claim 3, wherein the method further comprises the steps of:

processing the reservation information in each interior node between the edge nodes.

6. The method of claim 3, wherein the method further comprises the steps of:

processing the TNL flow identity in the edge node.

7. The method of claim 3, wherein the method further comprises the steps of:

responding to the PATH message by transmitting a RESV message comprising standard RSVP-TE objects and PHR and PDR objects in the reverse direction.

8. The method of claim 3, wherein the method further comprises the steps of:

responding to said PATH message by transmitting in the reverse direction a RESV message comprising standard RSVP-TE, PHR, PDR objects or AAL2_ LABEL or LABEL objects, and

inserting resource reservation confirmation information into the RESV message.

9. The method according to claim 1 or 2, wherein the first edge node is a radio network controller in the UTRAN and the second edge node is a node B in the UTRAN.

10. The method according to claim 1 or 2, wherein the second edge node is a radio network controller in the UTRAN and the first edge node is a node B in the UTRAN.

11. The method according to claim 1 or 2, wherein the first edge node is a radio network controller in the UTRAN and the second edge node is an interworking unit between an IP based part of the UTRAN and an AAL2/ATM part of the UTRAN.

12. The method according to claim 1 or 2, wherein the second edge node is a radio network controller in the UTRAN and the first edge node is an interworking unit between an IP based part of the UTRAN and an AAL2/ATM part of the UTRAN.

13. The method of claim 1, wherein the method further comprises the steps of:

the AAL2/ATM UTRAN part is configured by sending a PATH message including channel identification CID values, VPI/VCI values to neighboring nodes along the connection PATH.

14. The method according to claim 13, wherein the object LABEL REQUEST with ATM LABEL range is adapted to carry VPI/VCI values and the AAL2 LABEL REQUEST is adapted to carry channel identification CID values.

15. The method of claim 14, wherein the method further comprises the steps of:

responding to the PATH message and the AAL2_ LABEL _ REQUEST by transmitting a RESV message comprising at least an ATM LABEL object comprising a VPI and a VCI and an AAL2_ LABEL object comprising a channel identification CID of a connection.

16. The method of claim 15, wherein the method further comprises the steps of:

the LABEL and AAL2_ LABEL objects are processed by the same node in which the LABEL _ REQUEST and AAL2_ LABEL _ REQUEST were initiated.

17. The method according to claim 13 or 14, wherein the method further comprises the step of:

quality of service (QoS) in the ATM/AAL2 network portion is ensured by using AAL2 CAC.

18. The method of claim 14, wherein the less significant 8 bits of the object LABEL and the object LABEL REQUEST with AAL2 LABEL ranges include a channel identification CID value.

19. A method according to claim 13 or 14, when the interworking unit, IWU, is operating between the ATM network part and the IP network part, said method further comprising the steps of:

converting the Q.AAL2 and IP-ALCAP messages into said RSVP-TE based TNL signaling message.

20. An arrangement for controlling a user plane of a UMTS terrestrial radio access network, UTRAN, (102) comprising a first edge node (105) connected to a second edge node (104) via a transport network layer by using transport network layer, TNL, signalling, the arrangement comprising means for establishing a radio link by using a node B application part between the first (105) and second (104) edge nodes of the UTRAN (102), the arrangement characterized in that the arrangement comprises: means for transmitting RSVP-TE based TNL signaling messages between the first and second edge nodes for each TNL flow,

means for identifying each TNL flow by using RSVP-TE messages, wherein the objects SESSION and SENDER _ TEMPLATE comprise IP-based 5-tuple flow information, which is adapted to be used as TNL flow identity.

21. The arrangement according to claim 20, wherein the arrangement comprises means for establishing one RSVP-TE tunnel for each connection direction between the first edge node and the second edge node.

22. An arrangement according to any of claims 20-21, wherein the arrangement comprises means for starting TNL signalling by sending a PATH message comprising at least reservation information and a TNL flow identity, the reservation information being for an interior node.

23. The apparatus of claim 22, wherein the reservation information is bandwidth.

24. The apparatus of claim 22, wherein the apparatus comprises means for processing the reservation information in each interior node between the edge nodes.

25. The apparatus according to claim 22, wherein the apparatus comprises means for processing the TNL flow identity in the edge node.

26. The apparatus according to claim 22, wherein the apparatus comprises means for responding to the PATH message by transmitting a RESV message comprising standard RSVP-TE objects and PHR and PDR objects in the reverse direction.

27. The apparatus according to claim 22, wherein the apparatus comprises means for responding to the PATH message by transmitting a RESV message comprising standard RSVP-TE, PHR, PDR objects or AAL2_ LABEL or LABEL objects in the reverse direction, and means for inserting resource reservation confirmation information into the RESV message.

28. The apparatus according to claim 20 or 21, wherein the first edge node is a radio network controller in the UTRAN and the second edge node is a node B in the UTRAN.

29. The apparatus according to claim 20 or 21, wherein the second edge node is a radio network controller in the UTRAN and the first edge node is a node B in the UTRAN.

30. The apparatus according to claim 20 or 21, wherein the first edge node is a radio network controller in the UTRAN and the second edge node is an interworking unit between an IP-based part of the UTRAN and an AAL2/ATM part of the UTRAN.

31. The apparatus according to claim 20 or 21, wherein the second edge node is a radio network controller in the UTRAN and the first edge node is an interworking unit between an IP-based part of the UTRAN and an AAL2/ATM part of the UTRAN.

32. An arrangement according to claim 20, wherein the arrangement comprises means for configuring the AAL2/ATM UTRAN part by sending a PATH message comprising channel identification CID, VPI/VCI values to neighbouring nodes along the connection PATH.

33. The apparatus according to claim 32, wherein the object LABEL REQUEST with ATM LABEL range is adapted to carry VPI/VCI values and the AAL2 LABEL REQUEST is adapted to carry channel identification CID values.

34. The apparatus according to claim 33, wherein the apparatus comprises means for responding to the PATH message and the AAL2_ LABEL _ REQUEST by transmitting a RESV message comprising at least an ATM LABEL object and an AAL2_ LABEL object, wherein the ATM LABEL object comprises a VPI and a VCI and the AAL2_ LABEL object comprises a channel identification, CID, of a connection.

35. The apparatus according to claim 34, wherein the apparatus comprises means for processing the LABEL and AAL2_ LABEL objects by the same node in which the LABEL REQUEST and AAL2_ LABEL REQUEST were initiated.

36. An arrangement according to claim 32 or 33, wherein the arrangement comprises means for ensuring quality of service (QoS) in the ATM/AAL2 network part by using AAL2 CAC.

37. The apparatus of claim 33, wherein the less significant 8 bits of the object LABEL and the object LABEL REQUEST with AAL2 LABEL ranges include a channel identification CID value.

38. The apparatus of claim 32 or 33, when the interworking unit IWU operates between the ATM network part and the IP network part, comprising means for converting the q.aal2 and IP-ALCAP messages into said RSVP-TE based TNL signaling messages.