WO2016197999A1

WO2016197999A1 - Bier boundary node identification method and apparatus

Info

Publication number: WO2016197999A1
Application number: PCT/CN2016/086047
Authority: WO
Inventors: 廖婷
Original assignee: 中兴通讯股份有限公司
Priority date: 2015-10-30
Filing date: 2016-06-16
Publication date: 2016-12-15
Also published as: CN106656824A

Abstract

Disclosed is a Bit Indexed Explicit Replication (BIER) boundary node identification method. The method comprises: when a BIER boundary node constructs a message for advertising an identifier of a bit forwarding router (BFR) thereof, the BIER boundary node sets a first identification bit preset in the message, the first identification bit being used to identify whether the node is a boundary node; and the BIER boundary node floods the message in a BIER domain. The apparatus comprises a construction module and an advertising module.

Description

Method and device for identifying BIER boundary node

Technical field

Embodiments of the present invention relate to, but are not limited to, network communication technologies, and in particular, to a BIER (Bit Indexed Explicit Replication) technology in a multicast domain, a method and apparatus for identifying a BIER boundary node.

Background technique

IP multicast technology enables efficient data transmission from point to point in IP networks. It can effectively save network bandwidth and reduce network load, so it has a wide range of applications in real-time data transmission, multimedia conferencing, data copying, IPTV (interactive network TV), games and simulation. The current multicast technology generally adopts PIM (Protocol Independent Multicast) protocol (including PIM-SM (Protocol Independent Multicast-Sparse Mode) and PIM-DM (Protocol Independent Multicast-Dense Mode)), MSDP ( Multicast Source Discovery Protocol, etc. A common feature of these multicast protocols is the need to construct a control plane multicast tree. The multicast tree is used to logically arrange the network planes into a tree. The point-to-multipoint data forwarding and loop avoidance of multicast forwarding, etc., the intermediate nodes of the multicast routing protocol with the distribution tree as the core need to maintain the state of complex multicast forwarding information, with the scale of the network. Increasingly large, multicast data traffic is increasing, this kind of multicast technology faces increasing cost and operation and maintenance challenges.

To this end, the industry has proposed a new technology for constructing multicast forwarding paths, called BIER (Bit Indexed Explicit Replication) technology, which proposes a new type of configuration that does not need to be built. The multicast technology architecture of the multicast distribution tree is as shown in Figure 1. A router that supports the BIER technology is called a BFR (Bit-Forwarding Router). A multicast forwarding domain consisting of BFRs is called a BFR domain. On the edge of the BIER domain, the device that performs BFIR encapsulation on the user's multicast data is called the BFIR (Bit-Forwarding Ingress Router). The edge BFR device that decapsulates the BIER data packet is called BFER (Bit-Forwarding egress). Router, bit forwarding egress router), the multicast data is encapsulated into the BIER domain by BFIR, and is forwarded in the BIER domain depending on the header of the BIER, and via one or Multiple BFER devices leave the BIER domain. In the BIER domain, the device that receives and forwards the BIER message is called the transit BFR of the BIER message. A BFR can be either a BFIR role or a BFER role, depending on the encapsulation and decapsulation messages.

In the BIER domain, each BFR (the intermediate forwarding node may or may not be assigned) is assigned a globally unique bit position (bit position) in the entire BIER sub-domain. Each BFER will have its own bit. The position is flooded in the BIER domain using the IGP (Interior Gateway Protocol) protocol. All bit positions form a bitstring. The transmission and routing of data packets in the BIER domain depends on the bitstring. When other BFRs receive the header containing the BIER, they are forwarded based on the Bit Forwarding Table (bit forwarding table or bit index forwarding table) according to the bit string carried in the BIER header. This principle of forwarding based on the BIER bit will change the forwarding based on the construction of the multicast distribution tree to the unicast lookup and forwarding using the bit identifier, which greatly reduces the forwarding cost of the network.

Figure 2 depicts the BIER forwarding process. BFR1 is ingress BFR or BFIR, BFR5, BFR6, and BFR7 are both egress BFR or BFER. The bit positions of the three BFRs are 0001, 0010, and 0100, respectively. Egress BFR advertises its own in the BIER domain through the IGP protocol (such as the IS-IS (Intermediate System to Intermediate System) protocol or the OSPF (Open Shortest Path First) protocol). Bit position, BFR1 receives the BFR5, BFR6 and BFR7 bit position notifications, and saves this information in the local bit index forwarding table. When BFR1 receives a multicast packet and assumes that the multicast packet needs to be transmitted to BFR5 and BFR6, BFR1 calculates the value of the Bitstring of the packet as 0101 based on the mapping relationship saved in advance. The packet is encapsulated as a BIER packet. The Bitstring in the BIER Header is padded with 0101 and forwarded to BFR2. After receiving the packet, BFR2 searches for the entry in the previously stored bit index forwarding table. According to the entry, the packet needs to be forwarded to BFR3, and then the packet needs to be forwarded to BFR3. The Bitstring is paired with the F-BM (Forwarding Bit Mask) of the matching entry to obtain 0101. BFR2 refills the BIER message with 0101 as the Bitstring in the BIER Header, and forwards the message. After BFR3, BFR3 finds its own bit index forwarding table after receiving the message. BFR3 has 2 matching records, which respectively represent the next hop of the packet to BFR4 and BFR6. For the first entry, BFR3 will be Bitstring. The value of the operation is compared with the F-BM in the entry, and the result is 0001. In the second entry, the value of the Bitstring and the result of the F-BM operation are 0100. Then, BFR3 forwards the BIER message from the two interfaces to BFR4 and BFR6 respectively, wherein the BIER header of BFR4 has a value of 0001, and the value of the Bitstring of the BIER Header forwarded to BFR6 is 0100. For the BFR6 packet, the value of the bitstring is the same as the bit position that it advertises. It indicates that it is the destination of the packet and decapsulates the BIER packet. When the arrival packet arrives at the BFR4, the packet forwarding is forwarded to the BFR5, and the BIER packet is decapsulated by the BFR5. The multicast packet is transmitted in the BIER domain, and the multicast packet is The BFR1 node of the ingress is forwarded to the receiving nodes BFR4 and BFR6 of the multicast.

In the related art BIER technology, the announcement of the multicast group capability that the BIER node joins may be advertised through the IGP flooding, but for the intermediate forwarding node, the learning of the information is unnecessary, and the access of these multicast groups is unnecessary. The message only needs to be learned by the boundary node. Therefore, how to distinguish the current boundary and the intermediate node is a problem to be solved.

Summary of the invention

The following is an overview of the topics detailed in this document. This Summary is not intended to limit the scope of the claims.

Embodiments of the present invention provide a BIER boundary node identification method and apparatus, which can distinguish between an identification boundary and an intermediate node.

An explicit indexing BIER boundary node identification method based on a bit index provided by an embodiment of the present invention includes:

When the BIER border node constructs a message for advertising the BFR identifier of the local node bit forwarding router, the first identifier position preset in the message is used, and the first identifier bit is used to identify whether the node is a boundary node. The BIER boundary node floods the message in the BIER domain.

Optionally, the method further includes: when the BIER border node determines that the node is set as a border node, or determines that the node has a non-BIER interface, when constructing a message for advertising the BFR identifier of the node, The first identification position position preset in the message.

Optionally, the first identifier bit is used to identify whether the local node is a boundary node or an intermediate forwarding node.

Optionally, the method further includes: the BIER boundary node is configured to notify the local node BFR When the message is identified, the second identifier position preset in the message is used, and the second identifier bit is used to identify whether the node is an intermediate forwarding node.

Optionally, the preset first identifier bit is one of the reserved fields in the BIER information subtype length value TLV.

Optionally, the method further includes: when the BIER node that receives the message sends a BIER data packet to the BIER border node, forming a bit string bitstring of the BIER boundary node, where the BIER data packet is The bit string is carried to transmit the BIER data message to the BIER boundary node.

The embodiment of the present invention further provides a bit-index-based explicit copy BIER border node identifier device, which is located at a BIER border node, and the device includes:

The constructing module is configured to: when the message for advertising the BFR identifier of the local node forwarding router is configured, the first identifier is preset in the message, and the first identifier is used to identify whether the node is a border node. ;as well as

The notification module is set to flood the message in the BIER domain.

Optionally, the device further includes a determining module configured to determine whether the node is set as a border node, or to determine whether the node has a non-BIER interface;

The constructing module is configured to: when the determining module determines that the node is set as a border node, or determines that the node has a non-BIER interface, when constructing a message for advertising the BFR identifier of the local node, the message is The preset first identification position is set.

Optionally, the constructing module is further configured to, when constructing a message for advertising the BFR identifier of the local node, set a second identifier position preset in the message, where the second identifier bit is used to identify the local Whether the node is an intermediate forwarding node.

Optionally, the preset first identifier bit is one of the reserved fields in the BIER information type length value TLV.

The embodiment of the invention further provides a computer readable storage medium, which stores a computer executable finger The computer executable instructions are used to implement the above method.

With the solution in the embodiment of the present invention, the nodes in the BEIR domain can easily identify the boundary nodes. When the multicast information needs to be advertised between the boundary nodes, the boundary bit string is generated according to the BFR identifier of the learned boundary node, and the boundary nodes can be generated between the boundary nodes. The multicast information is mutually advertised without worrying about leaking information to the intermediate node, thereby also saving the resource processing occupation of the boundary information by the intermediate node.

Other aspects will be apparent upon reading and understanding the drawings and detailed description.

BRIEF abstract

1 is a network diagram of a BIER technology in the related art;

2 is a diagram of a BIER technology forwarding process in the related art;

3 is a BIER info sub-tlv package format diagram in the related art;

Figure 4 is a flow chart of the embodiment of the present invention;

5 is a package format diagram of a BIER info sub-tlv according to an embodiment of the present invention;

6 is a schematic structural view of a device according to Embodiment 2 of the present invention;

7 is a package format diagram of a third embodiment of application of the present invention;

FIG. 8 is a block diagram of a fourth embodiment of the present invention.

Embodiments of the invention

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments in the present application may be arbitrarily combined with each other.

The steps illustrated in the flowchart of the figures may be executed in a computer system such as a set of computer executable instructions. Also, although logical sequences are shown in the flowcharts, in some cases the steps shown or described may be performed in a different order than the ones described herein.

Embodiment 1

This embodiment describes a method for explicitly replicating a BIER boundary node based on a bit index. As shown in FIG. 4, the method includes the following steps:

Step 401: The BIER border node sets a first identifier position preset in the message when the message for advertising the BFR identifier of the local node is configured, and the first identifier bit is used to identify whether the node is a boundary node.

The first identifier is used to identify whether the node is a border node, for example, the first identifier is used to identify whether the node is a boundary node or an intermediate forwarding node.

Optionally, step 401 further includes:

When the BIER boundary node constructs a message for advertising the BFR identifier of the local node, the second identifier position preset in the message is used, and the second identifier bit is used to identify whether the local node is an intermediate forwarding node.

The preset first identifier bit is one bit in a reserved field in a BIER information subtype length value (TLV). 3 is a BIER info sub-tlv (BIER information sub-TLV) of ISIS in the related art, by using any one of the reserved bits in the reserved field, by identifying the bit position, it can identify that it is a boundary node, This identifier is referred to as an E identifier in the embodiment, as shown in FIG.

Step 402: The BIER boundary node floods the message in the BIER domain.

When the ISIS advertises the sub-tlv, the node in the entire BIER domain can know whether the node advertising the TLV is a boundary node.

Therefore, in the BIER domain, all nodes can know the information of all the border nodes in the domain. When a message only needs to be sent to the border node for sensing, the corresponding message can be sent to the border node according to the set information.

Embodiment 2

As shown in FIG. 6, the BIER boundary node identification device is located at the BIER boundary node, and includes a construction module 601 and a notification module 602:

The constructing module 601 is configured to: when the message for advertising the BFR identifier of the local node is configured, the first identifier position preset in the message is used, and the first identifier bit is used to identify whether the node is a border node;

The notification module 602 is configured to flood the message in the BIER domain.

Optionally, the device further includes a determining module, configured to determine whether the node is set as a border node, or to determine whether the node has a non-BIER interface; the constructing module is configured to determine the node in the determining module When it is set as a border node, or when it is determined that the node has a non-BIER interface, when the message for advertising the BFR identifier of the local node is constructed, the first identifier position preset in the message is set.

Optionally, the constructing module 601 is further configured to, when constructing a message for advertising the BFR identifier of the local node, set a second identifier position preset in the message, where the second identifier bit is used to identify the node. Whether it is an intermediate forwarding node.

It should be noted that the device is a device corresponding to the BIER boundary node identification method, and all the implementation manners in the foregoing method embodiments are applicable to the device embodiment, and the same technical effects can be achieved.

The following is illustrated by several application examples.

Application Example 1:

According to the boundary node condition configured by the user, each boundary node sets a preset E bit in the message when constructing a message for advertising the BFR identifier of the local node, and floods the message in the BIER domain, so that All other nodes in the BIER domain know that this node is a boundary node.

Application Example 2:

The BIER node determines whether the node is a boundary node according to the interface type of its interface, for example, If it is determined that the interface has a non-BIER interface, the node is considered to be a BIER boundary node, and the E bit preset in the message is set when constructing a message for advertising the BFR identifier of the local node. And flooding the message in the BIER domain, so that other nodes in the BIER domain are aware that the node is a boundary node.

Application Example 3:

In this embodiment, when the BIER intermediate node constructs a message for advertising the BFR identifier of the local node, the second identifier position preset in the message is used, and the second identifier bit is used to identify the local node as an intermediate node. In this example, the second flag is referred to as a T (Transit) bit, as shown in FIG.

The flag can also be used to indicate whether the node is an intermediate forwarding node or a boundary node. For example, T=1 indicates that the node is a boundary node, and T=0 indicates that the node is an intermediate node.

Application Example 4:

In this embodiment, the first identifier bit and the second identifier bit are set at the same time, that is, the Reserved field includes both T and E. As shown in FIG. 8, since there is only one attribute for the same node, it is impossible to be both a boundary node. It is also an intermediate node, so the T and E flag bits can also be used to verify that the node's location setting is normal.

A person skilled in the art should understand that the technical solutions of the embodiments of the present invention may be modified or equivalent, without departing from the spirit and scope of the technical solutions of the present application, and should be included in the scope of the claims of the present application.

One of ordinary skill in the art will appreciate that all or a portion of the above steps may be performed by a program to instruct related hardware, such as a processor, which may be stored in a computer readable storage medium, such as a read only memory, disk or optical disk. Wait. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above embodiment may be implemented in the form of hardware, for example, by implementing an integrated circuit to implement its corresponding function, or may be implemented in the form of a software function module, for example, executing a program stored in the memory by a processor. / instruction to achieve its corresponding function. Embodiments of the invention are not limited to any particular form of hardware and The combination of software.

Industrial applicability

Claims

A method for explicitly copying BIER boundary node identification based on bit index, comprising:

When the BIER border node constructs a message for advertising the BFR identifier of the local node bit forwarding router, the first identifier position preset in the message is used, and the first identifier bit is used to identify whether the node is a boundary node. The BIER boundary node floods the message in the BIER domain.
The method of claim 1 further comprising

When the BIER border node determines that the node is set as a border node, or determines that the node has a non-BIER interface, when the message for advertising the BFR identifier of the node is constructed, the first identifier position preset in the message is set. Bit.
The method of claim 1 wherein

The first identifier is used to identify whether the node is a boundary node or an intermediate forwarding node.
The method of claim 1 further comprising:

When the BIER boundary node constructs a message for advertising the BFR identifier of the local node, the second identifier position preset in the message is used, and the second identifier bit is used to identify whether the local node is an intermediate forwarding node.
The method of claim 1 wherein

The preset first identifier bit is one bit in a reserved field in the BIER information subtype length value TLV.
The method of claim 1 further comprising:

And the BIER node that receives the message, when sending the BIER data packet to the BIER border node, forms a bit string bitstring of the BIER border node, and carries the bit string in the BIER data packet, so as to The BIER data message is sent to the BIER boundary node.
An explicit indexing BIER boundary node identification device based on a bit index, located at a BIER boundary node, the device comprising:

The constructing module is configured to: when the message for advertising the BFR identifier of the local node forwarding router is configured, the first identifier is preset in the message, and the first identifier is used to identify whether the node is a border node. ;as well as

The notification module is set to flood the message in the BIER domain.
The apparatus according to claim 7, further comprising a judging module configured to determine whether the node is set as a border node, or to determine whether the node has a non-BIER interface;

The constructing module is configured to: when the determining module determines that the node is set as a border node, or determines that the node has a non-BIER interface, when constructing a message for advertising the BFR identifier of the local node, the message is The preset first identification position is set.
The apparatus according to claim 7, wherein

The first identifier is used to identify whether the node is a boundary node or an intermediate forwarding node.
The apparatus according to claim 7, wherein

The constructing module is further configured to: when the message for advertising the BFR identifier of the local node is configured, the second identifier position preset in the message is used, and the second identifier bit is used to identify whether the node is an intermediate forwarding node. .
The apparatus according to claim 7, wherein

The preset first identifier bit is one bit in a reserved field in the BIER information type length value TLV.