CN1254051C - User's data service sub speed delivering method in metropolitan area network transmission equipment - Google Patents

Abstract

The invention discloses a method for transmitting user data services at a sub-rate in a metropolitan area network by using a self-defined data frame containing nested labels. data frame; according to business requirements, nest tags (Tag) are embedded in the received user data frame to form a custom data frame, and send this data frame; the remote transmission device receives the tag with the nested The custom data frame of the label; the remote transmission device uses the nested label in the custom data frame to find the forwarding entry, deletes the nested label, and sends the user data frame to the user according to the forwarding entry. The above method can reduce costs by increasing supported user data services. In addition, after the tag is embedded, the VLAN ID in the user data frame may not be unique across the network, which simplifies the security isolation of user data.

Description

Sub-rate transmission method of user data service in metropolitan area network transmission equipment

field of invention

The invention relates to the field of communication transmission, in particular to a method for transmitting user data services in metropolitan area network transmission equipment.

Background technique

In metro transmission equipment, users rent bandwidth mainly based on the rate of SDH (Synchronous Digital Hierarchy), that is, the granularity of VC-TRUNK (virtual channel) bandwidth on the channel side of metro transmission equipment. That is to say, in the MAN equipment, the bandwidth leased by users can only be VC-12, VC-3, VC-4 and other levels, and the minimum level of VC-TRUNCK bandwidth granularity (VC-12) is 2.048Mbps. When the bandwidth rented by the user is less than 2.048Mbps or its multiple and the user occupies the VC-TRUNCK bandwidth alone, it will cause waste of the bandwidth of the metro transmission network. In order to make effective use of the bandwidth of the metro transmission network, the sub-rate transmission technology for user data services is mainly used at present. As shown in Figure 1, Ethernet data packets (also called data frames) carrying the same or different VLAN ID1 and VLAN ID2 (virtual local area network identification) from different ports transmit data packets through the same VC-TRUNCK, and in the terminal device Then separate the data.

At present, the existing sub-rate transmission technology solutions for user data services directly adopt the IEEE 802.1P/Q standard, that is, divide the metropolitan area network into multiple VLANs (virtual local area networks), and assign one or more VLANs to each enterprise. cannot communicate with each other. In this way, the data packets in the same VC-TRUNCK can be identified by the unique VLAN ID of the entire network, thereby realizing "port + VLAN" table lookup and forwarding. At the same time, using the priority defined by the 802.1P standard, different priorities can be assigned to VLANs, thereby realizing QoS (Quality of Service) features to a certain extent. Figure 2 shows an Ethernet data frame format supported by IEEE 802.1Q with a VLAN ID. The data frame is composed of a destination address field, a source address field, an 802.1Q header field, a length/type field, a data field, and a check field, wherein the 802.1Q header field consists of TPID (Tag Protocol Identifier) and TCI (Tag control information), they are collectively called VLAN Tag (virtual local area network tag). It can be seen from Fig. 2 that the VLAN ID defined by 802.1Q has only 12 bits, so the MAN can only support 4096 (2 ¹² ) VLANs at most. With the increase of the scale of the metropolitan area network, 4096 VLANs can no longer meet the needs of the business. In addition, since the division of VLANIDs within all enterprises must be planned uniformly in the entire MAN, the operation is very complicated.

Contents of the invention

One purpose of the present invention is to achieve end-to-end interconnection of large-scale VLANs at low cost by breaking through the limitation of LAN networking caused by the lack of VLAN IDs stipulated by IEEE 802.1Q. Another object of the present invention is to solve the troubles caused by the division of all internal VLAN IDs that must be planned uniformly in the entire metropolitan area network.

In order to achieve the above object, the present invention provides a method for transmitting user data services at a sub-rate in a metropolitan area network by using a self-defined data frame, the method comprising the following steps: a) forming a forwarding table by configuring each transmission device item; b) the transmission device receives the user's data frame; c) nests a nested tag (Tag) in the received user data frame according to business requirements to form a custom data frame, and sends the data frame; d ) The remote transmission device receives the custom data frame with the nested label; e) The remote transmission device uses the nested label in the custom data frame to find forwarding entries and deletes the nested label And send the user data frame to the user according to the forwarding table entry.

By using the label nested in the user data frame to find the forwarding channel, the limitation of 4096 in the prior art solution can be broken, so as to reduce the cost by increasing the supported user data services. In addition, since the VLAN ID in the user data frame may not be unique across the network after the tag is embedded, the security isolation of user data is simplified.

Description of drawings

The present invention will be described in more detail below in conjunction with multiple embodiments and with reference to the accompanying drawings.

Fig. 1 is the schematic diagram that the metropolitan area network transmission equipment receives and sends the user data frame;

Fig. 2 is the Ethernet frame format with VLAN ID supported by IEEE 802.1Q;

Fig. 3 is a schematic flow sheet of the general technical solution of the present invention;

Fig. 4 is a label nesting method according to the first embodiment of the present invention;

Fig. 5 is a tag nesting method according to the second embodiment of the present invention;

Fig. 6 is a label nesting manner according to the third embodiment of the present invention.

Detailed ways

Fig. 3 is a general flow diagram of the method for transmitting user data services at a sub-rate according to the present invention. As shown in Figure 3, in step 1, each transmission device receives a forwarding entry, and this forwarding entry can be configured and issued by the network administrator when multiple user data frames pass through the virtual channel between the transmission devices, or It can be configured and sent to each transmission device by the network administrator when the user leases the line. In step 2, the transmission device receives the user data frame through a Gigabit Ethernet or Fast Ethernet (GE/FE) port. Next, in step 3, the transmission device embeds a nested tag (Tag) in the user data frame through hardware, software, or a combination of hardware and software according to the needs of the business, thereby forming a custom data frame, and passing The virtual channel sends this custom data frame to the remote transmission device. In step 4, the remote transmission device receives the above-mentioned custom data frame through its GE/FE port. Finally, in step 5, after receiving the custom data frame with the nested tag, the remote transmission device extracts the nested tag from the custom data frame, and uses the extracted nested tag to find the entry, then delete the nested tags and forward the data frame to the user according to the forwarding entry.

It can be seen from the above that the object of the present invention is achieved by nesting tags in the user data frame to form a new custom data frame. For those skilled in the art, multiple known ways can be used to nest tags in the user data frame. The technical problem to be solved by the present invention is to use the existing method of nesting tags in data frames, according to the different nesting positions of tags in user data frames, and the concept of locality and globality of tags, the present invention provides The following implementations are provided.

The first embodiment: Nest a label in front of the 802.1Q of the user data frame, and the label uses a local variable

As shown in Figure 4, the VLAN nesting technology is adopted in the first embodiment, that is, before the VLAN Tag (that is, the 802.1Q tag header in Figure 2 ) of the 802.1Q data frame, another tag identical to the 802.1Q definition is added. The VLAN Tag. In this way, when the user service sub-rate is transmitted, when the data frame has the same 802.1Q VLAN ID, it can be identified by the nested VLAN ID. In the case of adopting the label nesting mode shown in Figure 4, its processing flow is as follows: 1) when there are multiple user data frames passing through a virtual channel between two transmission devices, the nested VLAN ID data area is configured by the network administrator To distinguish different user data services, and deliver forwarding entries to the two transmission devices. 2) The MAN transmission equipment receives the user's 802.1Q VLAN frame. 3) When there is sub-rate transmission of user data services, the MAN transmission equipment adds a nested VLAN Tag. 4) The remote MAN transmission device receives the data frame with the nested VLAN Tag. 5) When there is user business sub-rate transmission, the remote MAN transmission device deletes the nested VLAN Tag and sends the 802.1Q frame to the user according to the forwarding table entry. In the nested VLAN solution described in the first embodiment, the method of "Port (port) + VLAN + nested VLAN" is used to search for the forwarding channel. Here, the nested VLAN is a local variable, which together with VLAN and Port constitutes the destination address of the user data frame. Therefore, the VLAN ID in the user data frame does not need to be unique in the entire network, it only needs to configure the nested VLAN ID between the two nodes of the transmission device.

The second embodiment: a label is nested in front of the 802.1Q of the user data frame, and the label uses a global variable.

As shown in FIG. 5 , in the second embodiment, the tag nested before the 802.1Q tag consists of a VCLine field and a Type (type) field. Here, the inventor has introduced the concept of a VCLine ID (virtual channel line identification). When the user leases a line from the operator, a VCLine ID will be generated for each leased line configured, and the length of the VCLine ID can be customized by the user. In addition, the Type field is not used by the IEEE organization but can be used by device manufacturers. In the case of using the label nesting method shown in Figure 5, the processing flow is as follows: 1) When the network administrator configures the line leased by the user from the operator, the VCLine ID is issued to all In the table entry of the node. 2) The MAN transmission device receives the user's 802.1QVLAN frame. 3) Regardless of whether there is sub-rate transmission of user data services, the MAN transmission equipment will add the nested VLAN Tag to the data frame; 4) The remote MAN transmission equipment receives the data frame with VCLine ID. 5) The remote MAN transmission device deletes the VCLine ID and sends the 802.1Q frame to the user. Compared with the method of using "Port (port)+VLAN+nested VLAN" to search for forwarding channels in the first embodiment, this embodiment only needs to use "VCLine ID" to search, so it has higher forwarding efficiency. In addition, since the VCLine ID is a global variable, and its length can be customized by the user, there is no limit to the user data services it supports.

Embodiment 3: A label is nested behind the 802.1Q of the user data frame, and the label uses a local variable.

In the third embodiment, the MPLS nesting technology is adopted, that is, a tag identical to that defined in the MPLS (Multiprotocol Label Switching) protocol is added after the VLANTag of the 802.1Q data frame. The structure of the MPLS label is shown in FIG. 6 . When there is user service sub-rate transmission, the user data frame is identified by the Label field in the nested MPLS label. In the case of using the label nesting method shown in Figure 6, the processing flow is as follows: 1) When multiple user data frames pass through a virtual channel between two transmission devices, the network administrator configures the MPLS Label (label) to distinguish different user data services, and deliver the forwarding entries to the two transmission devices. 2) The MAN transmission device receives the user's data frame. 3) The MAN transmission equipment adds nested MPLS labels. 4) The remote MAN transmission device receives the data frame with the embedded MPLS label. 5) The remote MAN transmission device deletes the nested MPLS and sends the data frame to the user. In the nested MPLS scheme described in the third embodiment, the search for the forwarding table item is performed using the Label field in the MPLS label, and the forwarding table item adopts static configuration, and the user data service message is supported to be an MPLS type message. arts. As shown in FIG. 6 , since the length of the Label in the MPLS label is long enough (20 bits), it can meet the requirements of user services. Moreover, only one method is required to realize multiple configuration methods with or without sub-rates.

In this specification, the invention has been described in terms of several specific embodiments. Various modifications and changes can be made to the present invention by those skilled in the art without departing from the spirit and scope of the present invention. For example, in the first embodiment, the local variable nested tag is inserted in front of the VLAN Tag, but it can also be placed behind the VLAN Tag, and the nested tag can also use the global variable. Similarly, in the second and third embodiments, the positions of nested tags and variable types can also be changed. In addition, nested tags conforming to other communication protocol definitions can also be used. Various modifications without departing from the spirit of the present invention are within the protection scope of the appended claims of the present invention.

Claims (6)

1. carry out the method that the sub-speed of user data service transmits in a metropolitan area network, may further comprise the steps:

(a) by each transmission equipment being configured to form forwarding-table item;

(b) transmission equipment receives the user's data frame;

(c) in the user data frame that receives, be nested into nested label forming a self-defining data frame according to business demand, and send this Frame;

(d) the far-end transmission equipment receives the self-defining data frame that has described nested label; And

(e) the far-end transmission equipment utilizes described nested label lookup forwarding-table item in the described self-defining data frame to delete this nested label of described self-defining data frame then, according to forwarding-table item described user data frame is sent to the user.

2. the sub-speed transfer approach of user data service according to claim 1 is characterized in that, described nested label uses local variable or global variable.

3. the sub-speed transfer approach of user data service according to claim 2, it is characterized in that, described nested label is the VLAN Tag local variable identical with the 802.1Q label definition in the described user data frame, and it and described user data frame have been combined together to form described self-defining data frame.

4. the sub-speed transfer approach of user data service according to claim 2 is characterized in that described nested label is the global variable that contains custom field, and it and described user data frame have been combined together to form described self-defining data frame.

5. the sub-speed transfer approach of user data service according to claim 2 is characterized in that, described nested label is and the identical label local variable of mpls protocol definition that it and described user data frame have been combined together to form described self-defining data frame.

6. according to the sub-speed transfer approach of the described user data service of any one claim in the claim 3,4 or 5, it is characterized in that in step (c), described nested label is nested in the front or the back of the 802.1Q label of user data frame.

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