WO2011047583A1

WO2011047583A1 - Method and system for acquiring link information in layer 2 virtual private networks

Info

Publication number: WO2011047583A1
Application number: PCT/CN2010/076903
Authority: WO
Inventors: 吴波; 陈然
Original assignee: 中兴通讯股份有限公司
Priority date: 2009-10-19
Filing date: 2010-09-14
Publication date: 2011-04-28
Also published as: CN102045232A

Abstract

The present invention discloses a method and system for acquiring link information in Layer 2 Virtual Private Networks (L2VPNs), and the method includes: an egress Provider Edge (PE) device acquires link information of the links connecting with Custom Edge (CE) devices, generates statistic type values according to said link information, and transmits a message carrying said statistic type values to an ingress PE device; the ingress PE device acquires the statistic type values from the received message carrying said statistic type values and consequently acquires the link information of the links among each egress PE device and the CE devices connected with it; said message carrying the statistic type values can be a Label Distribution Protocol (LDP) announcement message, a Border Gateway Protocol (BGP) update message, or a Pseudo-wire Operation, Administration and Maintenance (PW OAM) message. By transmitting the message carrying the statistic type values to the ingress PE from the egress PE node, the present invention achieves the requirement that a root node statistically obtains the link information, such as the number, the minimum Maximum Transmission Unit (MTU), the lowest speed and the maximal speed of the links among the egress PE and the receivers CE.

Description

Method and system for acquiring link information in layer 2 virtual private network

Technical field

The present invention relates to a virtual private network (VPN), and more particularly to a method and system for acquiring link information in a Layer 2 virtual private network VPN.

Background technique

PWE3 is an end-to-end Layer 2 service bearer technology. It is a Layer 2 Virtual Private Networks (Layer 2 Virtual Private Networks). In the two PE (Provider Edge, Provider Edge) devices of the PSN (Packet Switched Network), it uses LDP/RS VP ( Label Distribution Protocol/Resource Reservation Protocol). As a signaling, through tunnels (possibly MPLS (Multi Protocol Label Switching), GRE, L2TPv3, or others), various Layer 2 services such as ATM (Asynchronous Transfer) are simulated on the Customer Edge (User Edge) side. Mode, Asynchronous Transfer Mode, TDM (Time Division Multiplexing), FR (Frame Relay), etc., enables Layer 2 data of the CE side to be transparently transmitted in the PSN network.

Pseudo-wire (PW) defined by the PWE3 working group includes point-to-point pseudowires.

(Point-to-point Pseudo-wire, referred to as Ρ2Ρ PW) and point-to-multipoint Pseudo-wire (referred to as Ρ2ΜΡ PW). Because P2P PW is mainly used for unicast IP forwarding, it does not meet the needs of L2VPN services such as Internet Protocol Television (IPTV) and clock distribution. Therefore, the P2MP PW technology is proposed. The P2MP PW is a one-way point-to-multipoint pseudowire, and a PW (Pseudo-wire) connected to the source transmits Layer 2 services to one or more receivers (or leaves). The basic functions of the P2MP PW include: encapsulating a Protocol Data Unit (PDU) of a specific service that arrives at the Access Circuits (AC), and sends them to the egress through the P2MP pseudowire. Egress Access Circuits (Egress ACs for short), and meet the simulation requirements such as timing and order. The entire P2MP PW is monitored using a Network Management System (NMS). If the NMS is uniformly notified through the ingress PE, efficient statistics can be achieved. In this scenario, the root node needs to collect link information such as the number of links between the egress PE and the receiver CE, the Maximum Transmission Unit (MTU), and the minimum rate and maximum rate. As shown in Figure 1, the root node PE1 needs to separately count the number of links between the egress PE2, PE3 and each CE, and the minimum MTU, minimum rate, and maximum rate on the link.

At present, a personal draft proposed by France Telecom in the Internet Engineering Task Force (IETF) PWE3 engineering group can only count the number of links between the exporting PE and the receiver CE and for PE and receiving. For each link between the CEs, the LDP advertisement message carrying different information is sent to the root node by the leaf PE node. The implementation is too complicated. At the same time, the root node PE obtains the relationship between the egress PE and the receiver CE. Link information method, currently, there is no solution.

Summary of the invention

The present invention provides a method and system for obtaining link information in a Layer 2 virtual private network, so that the root node can obtain a chain between the edge provider PE of the egress provider and all user edge devices CE connected to the edge device of the egress provider. Road information.

In order to solve the above problem, the present invention provides a method for obtaining link information in a Layer 2 virtual private network, which includes the following steps:

In the Layer 2 virtual private network, each egress provider edge device obtains link information between all user edge devices connected to the egress provider edge device and forms a statistic type value according to the link information;

The egress provider edge device sends a message carrying the statistic type value to the ingress provider edge device;

The ingress provider edge device receives the message carrying the statistic type value, and obtains a statistic type value from the message carrying the statistic type value, and then obtains the connection between each egress provider edge device and the egress provider edge device. Link information between all user edge devices. The statistical type value may include: the number of links, the smallest maximum transmission unit, the maximum rate, and the minimum rate. The message carrying the statistic type value may be a Label Distribution Protocol (LDP) advertisement message, or may be a Border Gateway Protocol (BGP) update message, or may be a pseudowired Operation Management and Maintenance (PW OAM) message. The format of the statistic type value in the message carrying the statistic type value may include: a type of the statistic type value, a length of the statistic type value, and a content of the statistic type value; the content of the statistic type value may include: a minimum maximum transmission unit, and a connection The number of incoming links, the minimum rate of access links, and the maximum rate of access links. The method may further include: when the message carrying the statistic type value is an LDP advertisement message, the Statistic TLV field is extended in the LDP advertisement message to carry the statistic type value; or, when the message carrying the statistic type value is a BGP update In the message, a new BGP sub-address family information is allocated in the BGP address family 196 in the MP-REACH-NLRI attribute of the BGP update message, which is used to indicate the extended P2MP PW NLRI field, and the Statistic in the extended P2MP PW NLRI. The TLV field is used to carry the statistic type value. The Statistic TLV field is extended in the PW OAM message to carry the statistic type value when the message carrying the statistic type value is a PW OAM message.

The present invention also provides a system for acquiring link information in a Layer 2 virtual private network, comprising: an ingress provider edge device, one or more egress provider edge devices, and each egress provider edge device is connected with multiple users. Edge device, where

The egress provider edge device is configured to: obtain, in a layer 2 virtual private network, link information between all user edge devices connected to the egress provider edge device, and form a statistic type value according to the link information, and Sending a message carrying the statistic type value to the ingress provider edge device;

The ingress provider edge device is configured to: receive a message carrying the statistic type value, obtain a statistic type value from the message carrying the statistic type value, and obtain the connection between each egress provider edge device and the egress provider edge device. Link information between user edge devices.

The statistical type value may include: the number of links, the smallest maximum transmission unit, the maximum rate, and the minimum rate. The message carrying the statistic type value may be a Label Distribution Protocol (LDP) advertisement message, or may be a Border Gateway Protocol (BGP) update message, or may be a pseudowired Operation Management and Maintenance (PW OAM) message. The format of the statistic type value in the message carrying the statistic type value may include: a type of the statistic type value, a length of the statistic type value, and a statistic type value The content of the statistical type value may include: the minimum maximum transmission unit, the number of access links, the minimum rate of the access link, and the maximum rate of the access link. The egress provider edge device may be further configured to: when the message carrying the statistic type value is an LDP advertised message, the Statistic TLV field is extended in the LDP advertised message to carry the statistic type value; or, when the statistic type value is carried When the message is a BGP update message, a new BGP sub-address family information is allocated in the BGP address family 196 in the MP-REACH-NLRI attribute in the BGP update message, which is used to indicate the extended P2MP PW NLRI field, the extended P2MP PW. The Statistic TLV field in the NLRI is used to carry the statistic type value. Alternatively, when the message carrying the statistic type value is a PW OAM message, the Statistic TLV field is extended in the PW OAM message to carry the statistic type value.

The method and system for obtaining link information in a Layer 2 virtual private network of the present invention carries a new LDP notification message, BGP update message, or PW OAM message when the egress node sends an LDP advertisement message, a BGP update message, or a PW OAM message to the root node (ie, the ingress PE). Type-Length-Value (TLV) - statistic TLV, so that the number of links between the egress PE and the receiver CE, the minimum MTU, the minimum rate, and the maximum rate are obtained by the root node statistics. The need for information.

BRIEF abstract

1 is a schematic diagram of a Layer 2 VPN network using P2MP PW technology;

2 is a flowchart of obtaining link information in a Layer 2 VPN network according to the present invention;

Figure 3 is a schematic diagram of a statistic TLV defined by the present invention;

4 is a schematic diagram of a position of a statistic TLV defined by the present invention in an LDP advertisement message; FIG. 5 is a schematic diagram of a position of a statistic TLV defined by the present invention in a PW OAM header; FIG. 6 is a new type-length-value defined by the present invention. (Type-Length-Value, abbreviated as TLV)-statistic TLV is a schematic diagram of the P2MP PW NLRI field in the MP-REACH-NLRI attribute carried in the BGP update message;

FIG. 7 is a flowchart of a method for acquiring link information in a Layer 2 VPN network according to Embodiment 1 of the present invention; FIG. 8 is a flowchart of a method for acquiring link information in a Layer 2 VPN network according to Embodiment 2 of the present invention; A flowchart of a method for obtaining link information in a Layer 2 VPN network in Embodiment 3. Preferred embodiment of the invention

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the accompanying drawings.

For a Layer 2 virtual private network, the ingress provider edge device PE, that is, the root node, needs to count the link information between the egress PE and the receiver CE, such as the number of links and the smallest transmission unit on the link ( Maximum Transmission Unit (MTU), link information such as minimum rate and maximum rate, but only the number of acquired links and complex problems can be realized in the prior art. The method and system for obtaining link information in a Layer 2 virtual private network of the present invention, when the egress PE node sends an LDP advertisement message, a BGP update message, or a PW OAM message to the root node, carries a new type-length- The value (Type-Length-Value, TLV for short)-statistic TLV, so that the root node needs to count the number of links between the egress PE and the receiver CE, the minimum MTU, the minimum rate, and the maximum rate. The statistic TLV, for convenience of description, is hereinafter referred to as "statistical type value".

A method for obtaining link information in a Layer 2 virtual private network according to the present invention includes the following steps:

Each of the egress provider edge devices (PEs) obtains link information of the connected user edge device (CE), and forms a statistic type value according to the link information, where the statistic type value includes: the number of links, the minimum maximum transmission Unit (MTU), maximum rate, minimum rate;

Each of the egress provider edge devices (PEs) sends a message carrying the statistic type value to the ingress provider edge device (PE);

The ingress provider edge device (PE) receives the message carrying the statistic type value, obtains the statistic type value from the message carrying the statistic type value, and obtains the connection of each egress provider edge device (PE) Link information for the User Edge Device (CE).

The statistic type value includes: a number of links, a minimum maximum transmission unit (MTU), a maximum rate, and a minimum rate.

Based on the method, the present invention further provides a system for acquiring link information in a Layer 2 virtual private network, including: an ingress provider edge device, one or more egress provider edge devices, and each An egress provider edge device is connected to multiple user edge devices CE, where:

The egress provider edge device is configured to: obtain link information of the user edge device connected to the egress provider device, form a statistic type value according to the link information, and send the statistic to the ingress provider edge device a message of type value;

The ingress provider edge device is configured to: receive a message carrying the statistic type value, and obtain link information of each egress provider edge device and the connected user edge device from the statistic type value.

In the above method and system, the format of the statistical type value (ie, Statistic TLV) is shown in FIG. 3, including:

• Types of Type-Length-Value (TLV), which are assigned by the Internet Assigned Numbers Authority (IAA). The Statistic TLV (TBD) shown in Figure 3 indicates that the type-length-value TLV type is Statistic TLV, which is used to count the information of the link.

• Length, which indicates the length of the TLV, in bytes.

• The content of the TLV value includes: the effective MTU, the number of ACs, the minimum rate of the access link, and the maximum rate of the access link, where:

-- a valid MTU, indicating the smallest maximum transmission unit, in bytes;

― The number of ACs (Attachment Circuits), which indicates the number of access links, used to count the number of access links.

- the minimum rate of AC, in bps (bits per second);

- The maximum rate of AC, in bps (bits per second).

In the above method and system, the message carrying the statistic type value may be a Label Distribution Protocol (LDP) advertised message, or a Border Gateway Protocol (BGP) update message, Or pseudowire operation management and maintenance (Pseudo-wire Operations, Administration and Maintenance, referred to as PW OAM) message.

For the location of the statistic TLV in the LDP Advertisement message, the BGP Update message, or the PW OAM message, refer to FIG. 4, FIG. 5 and FIG. 4 is a schematic diagram of the location of the statistic TLV defined by the present invention in the LDP advertisement message; FIG. 5 is a schematic diagram of the location of the statistic TLV defined in the PW OAM header of the present invention; FIG. 6 is a statistic TLV defined by the present invention carried in the BGP update. Schematic diagram of the P2MP PW NLRI field in the MP-REACH-NLRI attribute in the message. The specific manner of transmitting the statistic TLV by using the LDP advertisement message, the BGP update message, or the PW OAM message will be described in detail in conjunction with Embodiments 1, 2, and 3, respectively.

2 is a flowchart of obtaining link information in a Layer 2 VPN network according to the present invention. As shown in FIG. 2, the process of obtaining link information in a Layer 2 VPN network includes the following steps:

Step 21: The egress PE collects the number of links, the maximum transmission unit MTU, and the bandwidth between the CE and the receiver CE.

For example, for the Layer 2 VPN network using P2MP PW technology as shown in Figure 1,

The maximum transmission unit of AC1 has an MTU of 500 bytes and a rate of 3 Gbps.

AC2's maximum transmission unit has a MTU of 700 bytes and a rate of 1 Gbps.

AC3's maximum transmission unit has a MTU of 900 bytes and a rate of 10 Gbps.

Then, at the exit PE2, statistical information as shown in Table 1 is formed, that is, the content of the statistical type value of PE2 is obtained.

Table 1

Similarly, for the egress PE3, the link to the CE is connected.

AC4 has an MTU of 600 bytes and a rate of 3 Gbps. AC5 has an MTU of 700 bytes and a rate of 1 Gbps.

The AC6 has an MTU of 900 bytes and a rate of 10 Gbps.

The AC7 has an MTU of 800 bytes and a rate of 5 Gbps.

Then, at the exit PE3, statistical information as shown in Table 2 is formed, that is, the content of the statistical type value of PE3 is obtained.

Table 2

Step 22: The egress PE sends a message carrying the Statistic TLV to the ingress PE.

The egress PE can send the LDP advertisement message carrying the Statistic TLV, the BGP update message, or the PW OAM message to the ingress PE to implement the number of links, minimum MTU, minimum rate, and maximum between the egress PE and the receiver CE. rate. The egress PE2 sends a message carrying the statistics shown in Table 1 to the ingress PE1. The egress PE3 sends a message carrying the statistics shown in Table 2 to the ingress PE1. The carried information forms Statistic TLV information in the format shown in FIG.

The locations of the Statistic TLV in the LDP Advertisement message, BGP Update message, or PW OAM message can be seen in Figure 4, Figure 5 and Figure 6.

Step 23: The ingress PE receives the message carrying the Statistic TLV.

After receiving the message carrying the Statistic TLV, the ingress PE will form the statistics as shown in Table 3.

Minimum rate lGbps

Maximum rate lOGbps

Number of links 4

Minimum MTU 600 octets

PE3 minimum rate lGbps

Maximum rate lOGbps

table 3

Example 1

In this embodiment, the extended LDP advertisement message is used to carry the Statistic TLV.

FIG. 7 is a flowchart of a method for obtaining link information in a Layer 2 VPN network according to Embodiment 1 of the present invention. As shown in FIG. 7, the method for obtaining link information in a Layer 2 VPN network in Embodiment 1 includes the following steps. :

Step 71: The egress PE collects the number of links, the minimum MTU, the minimum rate, and the maximum rate between the CE and the receiver CE.

As shown in step 21, PE2 and PE3 form statistical information as shown in Table 1 and Table 2. Step 72: The egress PE sends an LDP advertisement message carrying the Statistic TLV to the ingress PE. If the egress PE is a leaf node of the PW tree, the egress PE sends an LDP advertisement message to the ingress PE to advertise the status of its access circuit (Access Circuits, AC for short). Here, a Statistic TLV field is extended in the LDP Advertisement message. The Statistic TLV field is shown in Figure 4 in the location of the LDP Advertisement message.

Step 73: The ingress PE receives the LDP advertisement message carrying the Statistic TLV, and obtains the Statistic TLV information. After receiving the LDP advertisement message carrying the Statistic TLV, the ingress PE will generate the statistics information as shown in Table 3 and obtain the link information related to the egress PE.

Example 2

In this embodiment, the extended PW OAM message is used to carry the Statistic TLV. In MPLS-TP If the tunnel and the pseudowire are both statically configured, the PW OAM message can be extended to implement the information about the number of links, the minimum MTU, the minimum rate, and the maximum rate between the egress PE and the receiver CE. .

FIG. 8 is a flowchart of a method for obtaining link information in a Layer 2 VPN network according to Embodiment 2 of the present invention. As shown in FIG. 8, the method for obtaining link information in a Layer 2 VPN network in Embodiment 2 includes the following steps. :

Step 81: The egress PE collects the number of links, the minimum MTU, the minimum rate, and the maximum rate between the CE and the receiver CE.

As shown in step 21, PE2 and PE3 form statistical information as shown in Table 1 and Table 2. Step 82: The egress PE sends a PW OAM message carrying the Statistic TLV to the ingress PE.

The format of the Statistic TLV is shown in Figure 3. The location of the PW OAM message is shown in Figure 5. In Figure 5, ACH TLV Header = 0, indicating that there is no ACH TLV field in the message, and the F field indicates that the following field is Statistic TLV.

Step 83: The ingress PE receives the PW OAM message carrying the Statistic TLV, and obtains the Statistic TLV information. After receiving the PW OAM message carrying the Statistic TLV, the ingress PE will generate the statistics information as shown in Table 3 and obtain the link information related to the egress PE.

Example 3

In this embodiment, the extended BGP update message is used to carry the Statistic TLV.

FIG. 9 is a flowchart of a method for obtaining link information in a Layer 2 VPN network according to Embodiment 3 of the present invention. As shown in FIG. 9, the method for obtaining link information in a Layer 2 VPN network in Embodiment 3 includes the following steps. :

Step 91: The egress PE collects the number of links, the minimum MTU, the minimum rate, and the maximum rate between the CE and the receiver CE.

As shown in step 21, PE2 and PE3 form statistical information as shown in Table 1 and Table 2. Step 92: The egress PE sends a BGP update message carrying the Statistic TLV to the ingress PE.

The format of the Statistic TLV is shown in Figure 3. The MP-REACH-NLRI attribute in the BGP update message carries the BGP address family (AFI) and the sub-address family. (Sub-Address Family Information, SAFI for short) information, the BGP address family (Address Family Information) 196 is assigned to the L2VPN. The present invention requires the IANA to assign a new BGP sub-address family information (Sub-Address Family Information) for indicating P2MP PW NLRI. FIG. 6 is a schematic diagram of a P2MP PW NLRI field in an MP-REACH-NLRI attribute carried in a BGP update message according to the present invention. In the NLRI field, multiple TLVs can be extended as needed. We extend only one TLV-Statistic TLV here.

Step 93: The ingress PE receives the BGP update message carrying the Statistic TLV, and obtains the Statistic TLV information. After receiving the BGP update message carrying the Statistic TLV, the ingress PE will generate the statistics information as shown in Table 3 and obtain the link information related to the egress PE.

The above is only the embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. All modifications, equivalents, improvements, etc., made within the spirit and scope of the invention are intended to be included within the scope of the appended claims.

Industrial applicability

Compared with the prior art, the present invention can implement the root node statistics to obtain the link information such as the number of links between the egress PE and the receiver CE, the minimum MTU, the minimum rate, and the maximum rate.

Claims

Claim

A method for obtaining link information in a Layer 2 virtual private network, comprising:

In the Layer 2 virtual private network, each egress provider edge device acquires link information between all user edge devices connected to the egress provider edge device and forms a statistical type value according to the link information;

The egress provider edge device sends a message carrying the statistic type value to an ingress provider edge device;

The ingress provider edge device receives the message carrying the statistic type value, and obtains a statistic type value from the message carrying the statistic type value, and then obtains the connection between each egress provider edge device and the egress provider edge device. Link information between all user edge devices.

2. The method according to claim 1, wherein the statistical type value comprises:

Number of links, minimum maximum transmission unit, maximum rate, and minimum rate.

3. The method according to claim 1 or 2, wherein

The message carrying the statistic type value is a label distribution protocol LDP advertisement message, or a border gateway protocol BGP update message, or a pseudowire operation management and maintenance PW OAM message.

4. The method according to claim 3, wherein the format of the statistic type value in the message carrying the statistic type value comprises:

The type of the statistic type value, the length of the statistic type value, and the content of the statistic type value; wherein the content of the statistic type value includes: a minimum maximum transmission unit, a number of access links, and a minimum rate of the access link And the maximum rate of access links.

5. The method of claim 4, further comprising:

When the message carrying the statistic type value is an LDP advertised message, the Statistic TLV field is extended in the LDP advertisement message to carry the statistic type value; or

When the message carrying the statistic type value is a BGP update message, a new BGP sub-address family information is allocated in the BGP address family 196 in the MP-REACH-NLRI attribute in the BGP update message, and is used to indicate the extended P2MP. PW NLRI field, extended P2MP PW Statistic TLV field in NLRI is used to carry statistical type values; or When the message carrying the statistic type value is a PW OAM message, a Statistic TLV field is extended in the PW OAM message, and is used to carry a statistic type value.

6. A system for obtaining link information in a Layer 2 virtual private network, comprising: an ingress provider edge device, one or more egress provider edge devices, and each egress provider edge device is connected to multiple user edge devices , among them,

The egress provider edge device is configured to: obtain link information between all user edge devices connected to the egress provider edge device in a layer 2 virtual private network, and form a statistic type value according to the link information, And sending a message carrying the statistic type value to the ingress provider edge device;

The ingress provider edge device is configured to: receive a message carrying the statistic type value, obtain a statistic type value from a message carrying the statistic type value, and obtain each egress provider edge device and the egress provider edge Link information between user edge devices connected to the device.

7. The system of claim 6, wherein the statistical type value comprises:

8. The system of claim 6 or 7, wherein

9. The system according to claim 8, wherein the format of the statistic type value in the message carrying the statistic type value comprises:

10. The system of claim 9, wherein the egress provider edge device is further configured to:

When the message carrying the statistic type value is a BGP update message, the BGP update is cancelled. In the MP-REACH-NLRI attribute, the BGP address family 196 assigns a new BGP sub-address family information to indicate the extended P2MP PW NLRI field. The extended P2MP PW NLRI Statistic TLV field is used to carry the statistic type. Value; or,

When the message carrying the statistic type value is a PW OAM message, a Statistic TLV field is extended in the PW OAM message, and is used to carry a statistic type value.