WO2008028384A1

WO2008028384A1 - A method and system for implementing the transmission control for the oam messages

Info

Publication number: WO2008028384A1
Application number: PCT/CN2007/001467
Authority: WO
Inventors: Min Li; Zhenyu Shi; Yang Zhang
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2006-08-30
Filing date: 2007-04-29
Publication date: 2008-03-13
Also published as: CN1913496A; CN100450101C

Abstract

A method for implementing the transmission control for the OAM messages includes: transmitting an OAM message carrying the destination MAC address and the ID information in the maintenance domain; after receiving the OAM message, if the entry corresponding to the destination MAC address is not found, then the OAM message is processed according to the ID information. A system and bridge device for implementing the transmission control for the OAM messages. In the case of the OAM message searching the transmission table unsuccessfully, the invention can process the OAM message according to the ID information.

Description

OAM packet forwarding control method and system

Technical field

The present invention relates to the field of network communications, and in particular, to a forwarding control method, system and apparatus for operating, managing, and maintaining OAM (Operations, Administration and Maintenance). Background of the invention

Ethernet technology is simple to use, inexpensive, and bandwidth can be continuously improved. It has been widely used as a service or as a network structure in enterprise networks, metropolitan area networks, and wide area networks. However, traditional Ethernet can be maintained and has low operational capability. As the scope of Ethernet promotion has gradually expanded, the demand for Ethernet OAM functions has become stronger and stronger.

The Ethernet OAM function can be divided into two parts: fault management and performance management. Among them, the protocol, 802.1ag ethoam defines the fault management function of the end-to-end Ethernet OAM, including: fault detection, fault identification (Ping), fault location and isolation (Tracert), and fault notification and alarm suppression.

Maintenance Domain (MD) is a part of the network or network involved in the 802.1ag fault management function. It is defined by a series of domain service access points (DSAPs). Different MDs pass their respective MD name to distinguish. The DSAP is the boundary point of the maintenance domain, such as a port of the bridge device, which provides connectivity services for the outside of the domain. There may also be an intermediate service access point (ISAP) in the maintenance domain. An intermediate node from one DSAP to another.

FIG. 1 is a schematic diagram of an example of a maintenance service in the prior art. Figure 1 shows a maintenance domain The example includes five bridge devices. The six DSAP coverage areas shown are maintenance domains with multiple ISAPs in between.

You can configure multiple service instances (such as DSAPs available for a user's services) in the maintenance domain as needed. Each service instance consists of multiple DSAPs with some common attributes (such as bandwidth), identified by an identification ID. .

Configuring a service instance is to establish a connectionless association between each DSAP in the service instance. That is, the maintenance association MA (Maintenance Association), the MA includes multiple maintenance nodes MP (Maintenance Point), as the MP of the DSAP. The Maintenance Association End Point (MEP) is called the Maintenance Association End Point (MIP). The Maintenance Association Intermediate Point MA is distinguished by a unique MA name in the entire maintenance domain. The MA name is formed together with the maintenance domain name. A unique identification ID that identifies the service instance.

2 is a schematic diagram of an example of a maintenance service of a manager's perspective in the prior art. Referring to FIG. 2, points a, c, e, and f are configured as DSAPs available to the user CI, thereby establishing a service instance related to the user CI and the corresponding maintenance alliance MA, and the other two DSAPs b and d are not used, and are not This service instance and MA. Fig. 3 is a schematic diagram showing an example of a maintenance service from a customer perspective in the prior art. Referring to Figure 3, the maintenance alliance MA in Figure 2 is viewed from the perspective of user C1. The MA consists of four DSAP nodes that belong to the same service instance.

The path between the two MPs of the same maintenance association can be detected by the 802.1 ag Mac Trace function. The link trace message (LTM) and the link trace response (LTR) are detected. The MIP path passed between the two MPs. The format of the IEEE 802. l ag link tracking message LTM is shown in Table 1: MD

1 Version OpCode Flags First TLV Offset Level

5 Transaction Identifier/Sequence Number

9 LTM TTL Field Original MAC Address Field

13

] 7 Target MAC Address Field

21 (Additional fields can be added,here,in future versions of the protocol)

5+

First Additional LTM TLVs

TLV

Offset

Last End TLV(O)

Where MD Level: identifies the MD level;

Version: OAM protocol version number;

OpCode: specifies the format and purpose of the protocol;

Flags: Determine the meaning of messages in different formats;

First TLV Offset: the offset of the first TLV in the message;

Transaction Identifier I Sequence Number: Send ID/Serial Number;

LTM TTL Field: The number of hops the LTM message passes through;

Original MAC Address Field: The MAC address of the MEP point that originally initiated the LTM 4 message;

Target MAC Address Field: The destination MAC address of the LTM trace;

Additional LTM TLVs: Added TLV, protocol extension;

End TLV: Flag The end of the TLV sequence TLV, which is the last TLV in the message.

Referring to FIG. 4, FIG. 4 is a schematic diagram of a transmission/response of a link tracking message in the prior art.

3 In the fourth, the bridge device A is the source bridge device, the bridge device B is the intermediate bridge device, and the bridge device C is the destination end bridge device. Specifically, the following steps are included:

Step 1: The bridge device A where the MEP is located multicasts the LTM packet in the MD. The LTM packet contains the destination MAC address.

Step 2: After receiving the LTM message through the MIP, the bridge device B sends the LTR packet to the bridge device A in the unicast mode; and searches for the entry corresponding to the destination MAC address in the LTM. If the search succeeds, the entry is based on the entry. Send the LTM packet to the next hop. In this example, the next hop is the bridge device C. Go to step 3. If the search fails, there are two processing methods. One is to discard the packet, and the LTM packet is sent. End; Second, send the message by broadcast, and go to step 3.

Step 3: After receiving the LTM sent by the bridge device B, the bridge device C determines that the destination MAC address in the LTM message is itself, and does not continue to send the LTM, but directly sends an LTR to the bridge device A. Bridge device A can calculate a path to bridge device C based on the information of the bridge device in the received LTR message.

In fact, the LTM packets sent by the source bridge device generally need to be forwarded by multiple intermediate bridge devices to reach the destination end bridge device; each intermediate bridge device that passes through must reply LTR packets to the source bridge device. The source bridge device can learn the information of all intermediate bridge devices passing through on the way to the destination end bridge device and record their MAC addresses. If a bridge device fails, the source bridge device will not receive the LTR packet it returns, so that fault location can be achieved.

However, the inventor of the present invention found that after receiving the LTM message, the intermediate bridge device broadcasts or discards the packet if the entry corresponding to the destination MAC address is not found. If all the LTM packets of the entry that does not match the destination MAC address are discarded, the fault will be correctly located. If all the LTM packets that do not match the entry corresponding to the destination MAC address are broadcast, May appear big on the network Broadcast broadcast packets, wasting network bandwidth. The basis of the forwarding behavior can be determined according to the command configuration, but this requires the administrator to configure on all the bridge devices, the configuration workload is large, and can not adapt to changes in the network topology, and the scalability is poor. Summary of the invention

The embodiment of the present invention provides a method, a system, and a device for controlling the forwarding of an OAM packet, and can process the packet when the entry corresponding to the destination address is not found.

An OAM packet forwarding control method includes:

Sending an OAM packet carrying the destination MAC address and the identifier information in the maintenance domain; and after receiving the OAM packet, if the entry corresponding to the destination MAC address is not found, the identifier is OAM packets are processed.

An OAM packet forwarding control system includes:

The source bridge device is configured to send an OAM packet carrying the destination MAC address and the identifier information in the maintenance domain.

The one or more intermediate bridge devices are configured to process the OAM packet according to the identifier information when the entry corresponding to the destination MAC address is not found after receiving the OAM packet.

A bridge device, comprising:

An identifier information adding module, configured to add first identifier information to the first OAM packet carrying the first destination MAC address;

a first maintenance node, configured to send the first OAM packet;

a second maintenance node, configured to receive a second OAM packet carrying the second destination MAC address and the second identifier information;

The identifier information identifying module is configured to: after receiving the second OAM packet, if the entry corresponding to the second destination MAC address is not found, according to the second identifier The information determines how the second OAM message is processed.

A bridge device, used as a source bridge device, comprising:

An identifier information adding module, configured to add identifier information to an OAM packet carrying a destination MAC address;

The maintenance node is configured to send the OAM packet.

A bridge device used as an intermediate bridge device, including:

The maintenance node is configured to receive an OAM message carrying the destination MAC address and the identifier information.

The identifier information identifying module is configured to determine, according to the identifier information, a processing manner of the OAM packet when the entry corresponding to the destination MAC address is not found.

The solution of the embodiment of the present invention only needs to carry the identifier information in the OAM packet. When the intermediate bridge device cannot find the entry corresponding to the destination MAC address, the intermediate bridge device processes the OAM packet according to the identifier information, and does not need an administrator. A lot of manual configuration operations are easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an example of a maintenance service in the prior art.

2 is a schematic diagram of an example of a maintenance service of a manager's perspective in the prior art.

FIG. 3 is a schematic diagram of an example of a maintenance service of a customer perspective in the prior art.

FIG. 4 is a schematic diagram of a transmission/response of a link tracking message in the prior art.

FIG. 5 is a flowchart of a method for controlling forwarding of OAM packets according to Embodiment 1 of the present invention. FIG. 6 is a flowchart of a method for controlling forwarding of OAM packets according to Embodiment 2 of the present invention. FIG. 7 is a schematic diagram of a forwarding control system for an AU message according to Embodiment 3 of the present invention. FIG. 8 is a schematic diagram of a forwarding control system for an OAM packet according to Embodiment 4 of the present invention. FIG. 9 is a schematic diagram of a forwarding control system for an OAM packet according to Embodiment 5 of the present invention. Mode for carrying out the invention

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

The embodiment of the present invention achieves the purpose of controlling OAM packet forwarding by extending the Flags field in the OAM packet or by causing the OAM packet to carry a new type length value TLV.

The OAM packet in the embodiment of the present invention may be a link tracking message LTM, a link tracking response message LTR, and a continuity detection message CCM.

Example 1

Referring to FIG. 5, this embodiment provides an OAM packet forwarding control method, which is described by taking the forwarding control of the link tracking packet LTM as an example, and specifically includes the following steps:

Step 101: Extend the 6th bit in the Flags field of the link tracking message LTM on the source bridge device, and name the extended bit. This embodiment is named B/D (Broadcast/Discard, wide). ^ Fan or discard) bit.

In the LTM message, the existing usage rules of the Flags field are:

HWOnly: (highest bit) If this bit is set, ie HWonly = 1, the MAC address table will be used to direct the LTM message to the next hop address. If this bit is not set, ie HWonly = 0, the MAC is used. The address table and/or CCM database to direct the LTM message to the next hop address.

Since the lower 7 bits in the Flags field are not used in the format of the existing IEEE 802. lag link tracking mode, any bit can be extended. In this embodiment, only the 6th bit is used. The example is explained.

Step 102: Set the newly extended bit. If the OAM message is important, set an important flag for the newly extended bit, such as setting B/D=l, otherwise it is not set, that is, B/D=0.

If B/D=l, the LTM message broadcasts the LTM in the VLAN of the virtual LAN, if If B/D=0, the LTM is discarded.

Step 103: The extended LTM packet is multicast and sent in the maintenance domain MD, where the LTM packet includes the destination MAC address.

Step 104: After receiving the LTM message, the intermediate bridge device determines whether the HWonly in the Flags field is equal to 1. If yes, go to step 105; otherwise, go to step 106.

Step 105: When HWonly - 1, first check the MAC forwarding table. If the entry corresponding to the destination MAC address in the LTM is not found, check the BD bit in Flags. If B/D=l, LTM message The LTM is broadcast in a VLAN (Virtual Local Area Network). If B/D=0, the LTM is discarded.

Step 106: When HWonly is set to 0, the MAC table is first queried. If the entry corresponding to the destination MAC address in the LTM is not found, the CCM database is queried, and if the table corresponding to the destination MAC in the LTM is still not found, In this case, the B/D bit is used for judgment. If B/D=l, the LTM message is broadcast in the VLAN. If B/D=0, the message is discarded.

In this step, you can also check the CCM database first, and then check the MAC forwarding table. If there is no MAC forwarding table, you can also check only the CCM database.

The above method determines that the processing method of the message is very simple and easy to implement by extending only one bit of the Flags field in the message.

Example 2

Referring to FIG. 6, this embodiment provides another method for controlling the forwarding of OAM packets. The forwarding control of the link tracking packet LTM is taken as an example. The specific steps are as follows:

Step 201: Extend the LTM message on the source bridge device, that is, carry a new TLV, and carry a new MAC address as the backup MAC address in the type domain of the TLV, and the standby MAC address may be the MAC address of the MIP. .

As shown in Table 2, the type field format of the TLV that has been used so far is: TLV Ty e field

End TLV 0

Port ID TLV 1

MAC Status TLV 2

Data TLV 3

Reply Iafortaatiou TLV 4

Reply Ingres TLV

Reply Egress TLV 6

Next Hop Identifier TLV

Reserved for definition by IEEE 802.1 8-30

Organization-Specific TLV 31

Reserved for defmiticn by ITU-T Y.1731 32-63

("-

Reserved for definition by IEEE 802.1 Table 2

0 ~ 7 has been used, 8 ~ 30 is reserved for IEEE802.1, and a new TLV can be added to any of the bits. In this embodiment, a new TLV is added to the bit of type = 8, named: Specified Next Hop Mac Address TLV, the TLV format is shown in Table 3:

table 3

Where 0, 1, 2, 3 represent the first few bytes of four bytes, 1, 5, 9 indicate The starting number of bytes of the field. This TLV - a total of 9 bytes.

The length of the MAC address is 6 bytes. The MAC address carried in the TLV can be a unicast address, a multicast address, or a broadcast address.

Step 202: The extended LTM packet is sent in the maintenance domain MD in a multicast manner, and the LTM packet includes the destination MAC address.

Step 203: After receiving the LTM message, the intermediate bridge device first checks the MAC forwarding table and/or the CCM database. If the entry corresponding to the destination MAC address in the LTM packet is not found, the standby MAC address carried in the TLV is determined. Is it a unicast address, a multicast address, or a broadcast address.

Step 204: If the alternate MAC address carried in the TLV is a unicast address, use the backup MAC address in the TLV to query the MAC forwarding table and/or the CCM database again. If an entry corresponding to the backup MAC address is found, The LTM packet is forwarded to the LTM packet. If no entry corresponding to the standby MAC address is found, the packet is discarded.

Step 205: If the standby MAC address carried in the TLV is a multicast address, the packet is sent in multicast mode.

Step 206: If the alternate MAC address carried in the TLV is a broadcast address, the packet is sent by broadcast.

In addition, the extended TLV can also be used in other types of ETHOAM (Operation, Administration and Maintenance of Ethernet) packets to guide the forwarding of packets.

By adopting the extended TLV to carry the specified alternate MAC address, the control is more flexible, and the standby MAC address can be a broadcast or a unicast address or a multicast address, which brings more users than simply expanding the flags domain. Positioning tools and strategies.

The above method is extended by using a fixed bit in the header, and in the case of using a hardware forwarding chip (such as a network processor) for forwarding, if the hardware forwarding chip can By identifying the extended TLV, the extended TLV can be directly identified by the hardware forwarding chip without the need for CPU participation. It is much more efficient to process the message directly through the hardware forwarding chip than to send the message to the CPU.

Example 3

Referring to FIG. 7, the present invention further provides an OAM packet forwarding control system, including the following modules:

An identifier information adding module, configured to add an identifier information to the OAM packet, and then send the identifier in the maintenance domain;

The identification information adding module specifically includes:

The extension and sending unit is configured to extend any one of the lower 7 bits of the Flags field of the OAM message. If the OAM message is important, the extension bit is set to be an important flag. Otherwise, the maintenance alliance endpoint is expanded. The OAM packet is sent in the maintenance domain. The OAM packet carries the destination MAC address.

The forwarding module is configured to maintain the OAM packet in the virtual local area network according to the identifier information, if the maintenance intermediate node receives the OAM packet, if the entry corresponding to the destination MAC address carried in the OAM packet is not found in the forwarding table, Broadcast or discard;

The forwarding module specifically includes:

The first text forwarding unit is configured to: after receiving the OAM packet, the intermediate node of the association checks the MAC forwarding table. If the entry corresponding to the destination MAC address is not found, if the extension bit of the packet is set with an important flag, the OAM is The message is broadcast in the virtual local area network, otherwise the OAM message is discarded.

Optionally, the first packet forwarding unit is further configured to: after receiving the OAM packet, the intermediate node of the association checks the MAC forwarding table, and if the entry corresponding to the destination MAC address is not found, the continuity detection packet database is checked. If the entry corresponding to the destination MAC address is still not found, if the extension bit of the packet is set with an important flag, the OAM packet is in the virtual local area network. Broadcast, otherwise discard OAM packets.

Example 4

Referring to FIG. 8, the present invention further provides another forwarding control system for OAM packets, including the following modules:

The identification information adding module specifically includes:

The alternate address setting unit is configured to add a type length value to the OAM packet, carry the backup MAC address in the type field of the type length value, and then send the OAM packet with the type length value and the destination MAC address in the maintenance domain. .

The forwarding module is configured to process, after receiving the OAM packet, the OAM packet is processed according to the identifier information, if the entry corresponding to the destination MAC address is not found;

The forwarding module specifically includes:

The second packet forwarding unit is configured to: after receiving the OAM packet, the intermediate node of the association checks the MAC forwarding table and/or the CCM database, and if the entry corresponding to the destination MAC address carried in the OAM packet is not found, The alternate MAC address carried in the type length value is forwarded.

Example 5

The present invention also provides another OAM packet forwarding control system, including a source bridge device and one or more intermediate bridge devices. See Figure 9, Figure 9 shows only one intermediate bridge device.

The source bridge device includes an identification information adding module and one or more MPs, where The information adding module is configured to add an identifier to the OAM packet carrying the destination MAC address. The MP is configured to send the OAM message with the destination MAC address in the maintenance domain.

The intermediate bridge device is configured to process the packet according to the identifier information in the OAM when the OAM packet is received, and the entry corresponding to the destination MAC address carried in the OAM packet is not found.

The intermediate bridge device includes an identification information identifying module and a plurality of MPs; the identification information identifying module is configured to identify the identification information of the OAM packet when the identifier corresponding to the destination MAC address carried in the OAM packet is not found, according to the identifier The information is used to determine the processing mode of the OAM packet. The MP is used to receive or send the OAM packet. For example, the identification information identification module can be a hardware forwarding chip, such as a network processor or the like.

In this embodiment, the identifier information adding module of the source bridge device may be a first expansion module, and is used to extend any one of the lower 7 bits of the Flags field of the OAM file. If the OAM packet is important, the extension will be extended. The bit is set to be an important flag; otherwise, it is not set; correspondingly, the identification information identifying module of the intermediate bridge device is the first identifying module, and after receiving the OAM packet, if the MAC address carried by the OAM packet is not found, The entry, if it is determined that the extension bit is set with an important flag, determines to broadcast the OAM message; if the extension bit does not set the important flag, discard the OAM message.

In this embodiment, the identifier information adding module of the source bridge device may further be a second extension module, configured to add a type length value to the OAM packet, where the type field of the type length value carries the standby MAC address; The identification information identifying module of the intermediate bridge device is a second identifying module, configured to determine, after receiving the OAM packet, an entry corresponding to the destination MAC address carried in the OAM packet, and determining the OAM according to the standby MAC address. The way the message is processed.

In this embodiment, the source bridge device and the intermediate bridge device are for one maintenance domain, In a practical application, the source bridge device in one maintenance domain may be the intermediate bridge device of another maintenance domain, and the intermediate bridge device in one maintenance domain may also be the source bridge device of another maintenance domain, so one bridge device can simultaneously Has the function of source bridge device and intermediate bridge device.

With the solution described in the embodiment of the present invention, the OAM packet needs to be carried in the OAM packet, and the intermediate bridge device does not need to process the OAM packet according to the identifier information when the entry corresponding to the destination MAC address is not found. The administrator performs a large number of manual configuration operations, which can adapt to changes in the network topology, and is scalable and easy to implement.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the present invention. Within the scope of protection.

Claims

Claim

A method for controlling forwarding of OAM packets, comprising: transmitting an OAM packet carrying a destination MAC address and identification information in a maintenance domain; and after receiving the OAM packet, failing to find and When the entry corresponding to the destination MAC address is described, the OAM packet is processed according to the identifier information.

2. The method according to claim 1, wherein the identification information is carried in an extension bit of a lower 7 bits of a Flags field of an OAM message, and if the OAM message is important, the extension bit is set. Important sign; otherwise not set.

The method according to claim 2, wherein, when the entry corresponding to the destination MAC address is not found, processing the OAM packet according to the identifier information includes:

Checking the MAC forwarding table and/or the continuity detection packet database, if the extension corresponding to the destination MAC address is not found, if the extension bit is set with an important flag, the OAM packet is broadcasted, if The extension bit is not set with an important flag, and the OAM packet is discarded.

The method according to claim 1, wherein the identifier information is an alternate MAC address carried in a type field of a type length value added in the OAM packet.

The method according to claim 4, wherein the processing the OAM packet according to the identifier information comprises:

Determining that the standby MAC address is a unicast address, a multicast address, or a broadcast address; if the standby MAC address is a unicast address, searching for an entry corresponding to the standby MAC address, if it is found to correspond to the standby MAC address The entry of the OAM packet is forwarded according to the entry; if the entry corresponding to the standby MAC address is not found, Discarding the OAM packet;

If the standby MAC address is a multicast address, the OAM packet is sent in a multicast manner;

If the standby MAC address is a broadcast address, the OAM packet is sent by broadcast.

The method according to any one of claims 1 to 5, wherein the OAM message is a link tracking message, a link tracking response message, or a continuity detection message.

An OAM packet forwarding control system, comprising: a source bridge device, configured to send an OAM packet carrying a destination MAC address and identifier information in a maintenance domain;

The one or more intermediate bridge devices are configured to process the OAM packet according to the identifier information when the entry corresponding to the destination MAC address is not found after the OAM packet is received.

8. A bridge device, comprising:

The identifier information adding module is configured to add the first identifier information to the first OAM packet carrying the first destination MAC address;

a first maintenance node, configured to send the first OAM packet;

The identifier information identifying module is configured to: after receiving the second OAM message, if the entry corresponding to the second destination MAC address is not found, the second identifier information is determined to be the second Handling of OAM packets.

The bridge device according to claim 8, wherein the identifier information adding module is a first expansion module, configured to lower a ratio of a Flags field of the first OAM packet by a ratio of 7 Any one of the special positions is expanded. If the first OAM message is important, the extension bit is set to be an important flag; otherwise, it is not set;

The identification information identifying module is a first identifying module, configured to: when the second OAM packet is received, if the entry corresponding to the second MAC address is not found, if the second is identified If the extension bit in the Flags field of the OAM packet is set to be an important flag, the second OAM packet is broadcasted. If the extension bit is not set with the important flag, the second OAM packet is discarded.

The bridge device according to claim 8, wherein the identifier information adding module is a second extension module, configured to carry the first standby MAC address in the first OAM packet;

The identification information identifying module is a second identifying module, configured to: after receiving the second OAM message, when the entry corresponding to the second MAC address is not found, according to the second OAM report The second alternate MAC address carried in the text determines the processing manner of the second OAM packet.

11. A bridge device, comprising:

The maintenance node is configured to send the OAM packet.

12. A bridge device, comprising: