WO2008141567A1 - Multi-protocol label switching network flow switch method and equipment - Google Patents

Multi-protocol label switching network flow switch method and equipment Download PDF

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Publication number
WO2008141567A1
WO2008141567A1 PCT/CN2008/070960 CN2008070960W WO2008141567A1 WO 2008141567 A1 WO2008141567 A1 WO 2008141567A1 CN 2008070960 W CN2008070960 W CN 2008070960W WO 2008141567 A1 WO2008141567 A1 WO 2008141567A1
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WO
WIPO (PCT)
Prior art keywords
forwarding table
forwarding
unit
switching
downlink
Prior art date
Application number
PCT/CN2008/070960
Other languages
English (en)
French (fr)
Inventor
Xin Lv
Zhenbin Li
Qingsong Xiao
Bing Wu
Guangdong Zhu
Original Assignee
Huawei Technologies Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Huawei Technologies Co., Ltd. filed Critical Huawei Technologies Co., Ltd.
Priority to EP08748566.0A priority Critical patent/EP2099174B1/en
Publication of WO2008141567A1 publication Critical patent/WO2008141567A1/zh
Priority to US12/617,953 priority patent/US8155124B2/en
Priority to US13/409,690 priority patent/US20120163387A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/50—Routing or path finding of packets in data switching networks using label swapping, e.g. multi-protocol label switch [MPLS]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/02—Topology update or discovery
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/02—Topology update or discovery
    • H04L45/023—Delayed use of routing table updates

Definitions

  • the invention relates to a routing and forwarding technology in the field of communication networks, in particular to a technology for switching network traffic.
  • Multi-Protocol Label Switching As a key technology of next-generation networks, Multi-Protocol Label Switching (MPLS) technology plays an increasingly important role in IP networks.
  • MPLS Multi-Protocol Label Switching
  • label switching is used to forward data packets, which can flexibly control the routing of the network. It is also widely used in traffic engineering, virtual private network (VPN), and quality of service (QoS) control.
  • the path forwarded by the packet in the MPLS network is called the Label Switching Path (LSP).
  • LSP Label Switching Path
  • MPLS TE MPLS traffic engineering
  • the control plane of the router After the new label switching path is successfully established, the control plane of the router immediately sends an uplink forwarding table, also known as the Incoming Label Map (ILM) and the downstream forwarding table. It is also called the next hop label forwarding entry (NHLFE, Next). Hop Label Forwarding Entry ) To the forwarding unit, replace the pre-switching ILM entries and NHLFE entries, and the traffic is switched to The new label switching path, the control plane deletes the label switching path before switching, and completes the traffic switching.
  • ILM Incoming Label Map
  • NHLFE Next hop label forwarding entry
  • NHLFE is used to describe the operations that the router performs on tags, including Push, Pop, and Swap.
  • the ingress label mapping is the process by which the label switched route maps the label to the next hop label forwarding entry.
  • a mapping table of input/output labels is established; for the received label group, the label switching router only needs to find the corresponding NHLFE according to the inbound label mapping ILM table, and then performs the data packet. Forward.
  • the sending of the ILM entry and the NHLFE entry may be out of synchronization, resulting in a brief interruption of traffic. If the ILM entry is slower than the NHLFE entry, the ILM entry has not been replaced before the switchover, and the NHLFE entry has been replaced with the new NHLFE entry. . If this happens, the ILM entry cannot be matched to the new NHLFE until the ILM entry is also replaced, causing traffic to be interrupted for a short period of time. In addition, the upstream and downstream node forwarding table transmissions are not synchronized, which may cause a brief interruption of traffic.
  • Embodiments of the present invention provide a method for switching traffic of an MPLS network and a network node device, which reduces the occurrence of traffic interruption during the traffic switching process, thereby improving the stability and availability of the MPLS network traffic.
  • the method includes the steps of:
  • An embodiment of the present invention further provides a network node device, where the device includes: a data receiving unit, configured to receive data from other nodes in the network;
  • a forwarding unit configured to forward, according to the forwarding table, data received by the data receiving unit
  • a signaling receiving unit configured to receive a message that the label path is successfully established
  • a forwarding table generating unit configured to generate a forwarding table according to the message that the label path is successfully established, where the forwarding table includes an uplink forwarding table and a downlink forwarding table;
  • the forwarding table sending unit is configured to send the downlink forwarding table generated by the forwarding table generating unit to the forwarding unit at the first time, and send the uplink forwarding table generated by the forwarding table generating unit to the forwarding at the second time unit.
  • the method for switching the MPLS network traffic provided by the embodiment of the present invention and the network node device ensure the stability of the traffic during the flow switching process to prevent the traffic from being interrupted by ensuring the processing sequence of the events during the traffic switching process.
  • Figure 1 shows the path of the MPLS network protocol label.
  • FIG. 2 is a flowchart of MPLS network traffic switching according to an embodiment of the present invention.
  • FIG. 3 is a detailed flowchart of step S202 in FIG. 2.
  • FIG. 4 is a detailed flowchart of step S203 in FIG. 2.
  • FIG. 5 is a detailed flowchart of step S204 in FIG. 2.
  • FIG. 6 is a structural block diagram of a network node device according to an embodiment of the present invention.
  • the path A-B-C-D-E is the label switching path (LSP) of a multi-protocol label switching network.
  • the path AGC is used to protect the Node B and its related links.
  • the path BGD is used to protect the Node C and its related links.
  • the path CFE is used to protect the Node D and its related links.
  • the path DFE is used to protect the The link DE is protected. If the link of the B-C segment fails, traffic on the node B can be immediately switched to the B-G-D path to avoid packet loss. Fast rerouting is a temporary protection method. After a link failure occurs, the primary tunnel will immediately trigger the creation of a new label switching path. After the new label switching path is established successfully, the traffic will be switched to the newly created label switching path.
  • this embodiment provides a method for switching traffic of a multi-protocol label switching network.
  • the ingress node of a label switching path LSP receives a resource reservation message (RESV, Resource Reservation) indicating that the new label switching path is successfully created (step S201), generating a new uplink and downlink forwarding table, the new The message that the label switched path is created successfully records various information required for traffic engineering, such as session serial number, tag object, resource and stream object path record, and so on.
  • RESV Resource Reservation
  • Step S202) to the forwarding unit after the forwarding of the new downlink forwarding table is completed, after the node configures a new downlink forwarding table, the control plane of the network node device of the ingress node sends the saved The new uplink forwarding table (step S203), the forwarding unit forwards the data according to the new forwarding table, so that the traffic switching is implemented, and after the traffic switching succeeds, the old forwarding table before the switching in the forwarding unit is deleted (step S204).
  • the label switching path A-B-C-D-E of the multi-protocol label switching network is switched to the label switching path A-G-C-D-E.
  • the ingress node A receives the new label switching path A-G-C-D-E to create a successful message (Resource Reservation)
  • a new uplink and downlink forwarding table is generated.
  • the control plane of the node A saves the uplink forwarding entry label mapping (ILM entry), for example, in its control plane or a storage unit, and its control plane sends a downlink forwarding table next hop label forwarding entry (NHLFE entry). .
  • the forwarding table is updated to the new ILM entry and the NHLFE entry, the traffic is successfully switched.
  • the control plane deletes the tunnel A-B-C-D-E before the switchover.
  • the traffic master tunnel is the tunnel A-G-C-D-E.
  • step S202 a detailed flowchart of step S202.
  • a path deletion timer is started at the same time that the ingress node of the label switching path receives the new label switching path creation success message (step S301), and then the control plane saves the new uplink forwarding table ILM (step S302) and transmits the new downlink forwarding table NHLFE. (Step S303), step S302 and step S303 can also be performed simultaneously.
  • a traffic switching timer is started (step S304). Referring to FIG.
  • step S203 after the traffic switching timer expires, the control plane sends an uplink forwarding table ILM.
  • the refinement flowchart of step S204 deletes the old forwarding table before switching when the deletion path timer expires.
  • the new label switching path creation success event triggers the path deletion timer, and the control plane sends a new downlink forwarding table event to trigger the flow switching timer.
  • the user can change the delay time of the timer by itself, and the arrival time of the path deletion timer expires. The time is greater than the flow switching timer.
  • the path deletion timer is started when the ingress node A receives the new label switching path creation success message, and then the control plane of the node A saves the new uplink forwarding table ILM.
  • the control plane sends a new downlink forwarding table NHLFE but does not replace the downstream forwarding table NHLFE before handover.
  • the uplink information of the ingress node A is the uplink forwarding table ILM before the handover, and the downlink forwarding table NHLFE and the new downlink forwarding table NHLFE coexist in the downlink information, that is, the downlink forwarding table NHLFE of the path A-B-C-D-E and the path A-G-C-D-E coexist in the node A.
  • the control plane of the ingress node A sends the downlink switch to the NHLFE to start the traffic switch timer. After the forwarding of the new downlink forwarding table is completed, the control plane sends the uplink forwarding table ILM of the node, and the new uplink forwarding table ILM replaces the uplink forwarding table ILM before the handover. In this case, the uplink information of the ingress node A is the new uplink forwarding table ILM. However, the downstream forwarding table NHLFE of the path ABCDE and the path AGCDE still coexist in the A node. After the path deletion timer expires, the control plane deletes the label switching path before the switching, that is, deletes the path ABCDE and related entries.
  • the protocol exchange path is a general protocol exchange path, and may also be a constraint-based protocol exchange path. The steps and methods of traffic switching when the switching path is a constraint-based protocol switching path are still as described above.
  • the multi-protocol label switching network traffic switching method is used to send a new downlink forwarding table NHLFE immediately after the ingress node A of the label switching path receives the message that the label switching path is successfully created, but does not send a new uplink forwarding.
  • the ILM is published, but the new uplink forwarding table ILM is saved, and the traffic switching timer is started. When the timer expires, the new uplink forwarding table ILM is sent.
  • the label switching path ABCDE before switching will not be deleted immediately. If the path deletion timer expires, the label switching path ABCDE before the switching is triggered.
  • the traffic switching timer and the path deletion timer can be set to default values or configured.
  • the traffic switching method in the embodiment of the present invention uses a timer to ensure the processing sequence of events in the flow switching process, and buffers the short-time coexistence of the old and new forwarding tables, thereby reducing the possibility of traffic interruption during the traffic switching process.
  • the method of the MPLS network traffic switching method of the present invention is shown.
  • the difference from the first embodiment is that the second embodiment does not need to set a path deletion timer.
  • a new label switching path creation success message is received at the ingress node of the label switching path to generate a new uplink forwarding table and a downlink forwarding table, and a new downlink forwarding table is sent first, and the forwarding unit of the ingress node generates the new downlink forwarding table.
  • a feedback message and the feedback message is sent back to the control plane. After receiving the feedback message, the control plane considers that the new downlink forwarding table is sent, and then the control plane sends a new uplink forwarding table.
  • the multi-protocol label switching network traffic switching method is used to send a new downlink forwarding table NHLFE immediately after the ingress node A of the label switching path receives the message that the label switching path is successfully created, but does not send a new uplink forwarding.
  • the ILM is published, but the new uplink forwarding table ILM is saved, and the new uplink forwarding table ILM is sent after the new downlink forwarding table is forwarded.
  • the same effect as the first embodiment can be achieved by the above method.
  • An embodiment of the present invention further provides a network node device.
  • a network node device Referring to FIG. 6, a structural block diagram of the network node device.
  • the network node device 10 provided in this embodiment includes: a signaling receiving unit 101, a timer unit 102, a control plane 104, a forwarding unit 105, and a data receiving unit 106.
  • the control plane 104 is connected to and controlled by the data receiving unit 106, the signaling receiving unit 101, the timer unit 102, and the forwarding unit 105, respectively, to implement the units. Communication.
  • the forwarding unit 105 further includes a feedback message generating unit, and the forwarding unit 105 generates a feedback message after receiving the forwarding table sent by the control plane, and informs the control plane 104 that the forwarding unit 105 has received the forwarding table that it sends.
  • the control plane 104 includes a forwarding table generating unit 1041, which generates a new uplink and downlink forwarding table when it receives a new label switching path creation success message; a forwarding table sending unit 1042, configured to receive a new downlink forwarding table, and The downlink forwarding table is sent to the forwarding unit at the first moment, and at the second moment, the new uplink forwarding table is received, and the uplink forwarding table is sent to the forwarding unit.
  • the control plane 104 is further responsible for tasks such as label allocation, establishment and transmission of forwarding tables, and deletion of label switching paths.
  • the network node device may further include a storage unit 103, and the forwarding table established by the control plane 104 temporarily stores the forwarding table in the storage unit 103 when it is not immediately transmitted.
  • the storage unit 103 can be disposed in the control plane 104.
  • the signaling receiving unit 101 is configured to receive signaling, a message, and the like in the network, for example, a message that the label switching path is successfully created.
  • the data receiving unit 106 is configured to receive a data packet transmitted in a network.
  • the timer unit 102 is configured to set and start a timeout timer.
  • the timer unit 102 includes a flow switching timer 1021 and a path deletion timer 1022.
  • the signaling receiving unit 101 receives the message that the label switching path is successfully created, and triggers the start path deletion timer 1022.
  • the control plane 104 can trigger the flow switching timer 1021 when sending the forwarding table.
  • the timers are all timeout timers.
  • control plane 104 is triggered to send a forwarding table temporarily stored in the control plane 104 or in the storage unit 103.
  • the forwarding unit 105 forwards the data packet received by the data receiving unit 1012 according to the forwarding table sent by the control plane.
  • the control plane 104 When performing network traffic switching, if the network node device is an ingress node of a label switching path, the control plane 104 establishes a new forwarding table when its signaling receiving unit 101 receives a message that the label switching path is successfully created, and if necessary, The forwarding table is sent or temporarily stored.
  • the signaling receiving unit 101 receives the start of the timer list while receiving the successful completion of the label switching path creation.
  • the path deletion timer 1022 in the element 102 When the control plane 104 sends the forwarding table (the first time), the traffic switching timer 1021 is triggered. After the traffic switching timer 1021 expires (the second time), the control plane sends the temporary presence in the control plane 104 or the storage unit 103. Published.
  • the control plane deletes the forwarding table before switching.
  • the forwarding unit 105 forwards the data packet received by the data receiving unit 106 according to the forwarding table.
  • the network node device completes the traffic switching, and can reduce the possibility of traffic interruption during the traffic switching process.
  • the traffic switching timer 1021 may be omitted, and a forwarding message generating unit is included in the forwarding unit 105.
  • the forwarding table generating unit 1041 After the forwarding table generating unit 1041 generates the forwarding table, the forwarding table is forwarded.
  • the sending unit 1042 sends a new downlink forwarding table (first time) to the forwarding unit 105.
  • the feedback message generating unit After the forwarding unit 105 receives the new uplink forwarding table, the feedback message generating unit generates a feedback message to the signaling receiving unit 101, and receives the signaling.
  • the control plane control transmitting unit 1042 After receiving the feedback message (the second time), sends a new uplink forwarding table.
  • the control plane 104 creates a new forwarding table based on the routing information and sends or temporarily stores the forwarding table as needed.
  • the control plane 104 triggers the initiation of the traffic switching timer 1021 when the forwarding table is sent. After the traffic switching timer 1021 times out, the control plane transmits a forwarding table temporarily stored in the control plane 104 or in the storage unit 103. After the path deletion timer 1022 expires, the control plane deletes the forwarding table before switching.
  • the forwarding unit 105 forwards the data packet received by the data accepting unit 1012 according to the forwarding table. At this point, the network node device completes the traffic switching, and can reduce the possibility of traffic interruption during the traffic switching process.

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Description

一种多协议标签交换网络流量切换的方法及设备
技术领域
本发明涉及通信网络领域的路由及转发技术， 特别是一种网络流量 切换的技术。
发明背景
作为下一代网络的关键技术， 多协议标签交换 （MPLS , Multi - Protocol Label Switching )技术在 IP网络中扮演着越来越重要的角色。 在 MPLS网络中使用标签交换来转发数据包， 可以对网络的路由进行灵 活控制， 它在流量工程、 虚拟专用网 （VPN )、 服务质量（QoS )控制等 方面也广泛应用。数据包在 MPLS网络中转发的路径称为标签交换路径 ( LSP, Label Switching Path )„
随着 MPLS技术在 IP网络多业务承载中的广泛应用， MPLS网络的 流量切换已成为重要课题， 在网络故障检测、 建立流量保护路径时都会 遇到流量切换问题。 所以， 流量切换技术的改进对于提高 MPLS网络的 可用性和稳定性具有关键意义， 可以保证网络流量不被中断。
MPLS网络中标签交换路径建立以后， 用户如果修改 MPLS流量工 程（ MPLS TE )的隧道配置或者在快速重路由（ FRR Fast Reroute )切换 时都会发生流量切换。 现有技术中 MPLS网络流量切换方法为：
新的标签交换路径建立成功后， 路由器的控制平面立即发送上行转 发表， 又称为入标签映射 ( ILM, Incoming Label Map )和下行转发表， 又称为下一跳标签转发入口（ NHLFE, Next Hop Label Forwarding Entry ) 给转发单元， 同时替换掉切换前 ILM表项和 NHLFE表项， 流量切换到 新的标签交换路径，控制平面删除切换前标签交换路径，完成流量切换。
NHLFE用于描述路由器对标签执行的操作， 包括入栈（Push )、 出 栈（Pop )和交换（Swap )。 入标签映射是标签交换路由将标签映射到下 一跳标签转发入口的过程。 在标签交换路径的每一个标签交换路由器 上， 都建立输入 /输出标签的映射表； 对于接收到的标签分组， 标签交换 路由器只需根据入标签映射 ILM表找到相应的 NHLFE, 然后对数据包 进行转发。
现有技术的这种 MPLS网络流量切换方法，可能会出现 ILM表项与 NHLFE表项发送不同步的情况， 从而导致流量短暂中断。 如果 ILM表 项比 NHLFE表项发送的慢，在一段很短的时间内，就会出现切换前 ILM 表项还没有被替换， 而切换前 NHLFE表项已经被替换为新的 NHLFE 表项的现象。如果出现这种情况，则直到 ILM表项也被替换之前， ILM 表项无法匹配到新的 NHLFE, 会造成流量在短时间内中断。 另夕卜， 上 下游节点转发表发送不同步也会造成流量短暂中断。 如果下游节点的转 发表还没有发送完， 上游节点的流量已经切换到新的标签交换路径上， 这时也会造成流量的短暂中断。 而流量中断的出现则会严重影响网络的 可用性和稳定性。 发明内容
本发明的实施例提供一种 MPLS网络流量切换的方法及网络节点设 备， 减少流量切换过程中流量中断的发生， 从而提高 MPLS网络流量的 稳定性和可用性。
所述方法包括步骤：
接收标签交换路径建立成功的消息，
根据所述标签交换路径建立成功的消息生成上行转发表和下行转发 表；
将所述下行转发表发送至转发单元；
所述下行转发表转发完成后将所述上行转发表发送至转发单元； 转发单元根据所述上行转发表和所述下行转发表进行流量转发。 本发明的实施例还提供一种网络节点设备， 所述设备包括： 数据接收单元， 用于接收来自网络中其它节点的数据；
转发单元， 用于根据转发表对所述数据接收单元所接收的数据进行 转发；
信令接收单元， 用于接收标签路径建立成功的消息；
转发表生成单元， 用于根据所述标签路径建立成功的消息生成转发 表， 所述转发表包括上行转发表和下行转发表；
转发表发送单元， 用于在第一时刻将所述转发表生成单元所生成的 下行转发表发送给转发单元， 并在第二时刻将所述转发表生成单元所生 成的上行转发表发送给转发单元。 本发明实施例提供的 MPLS网络流量切换的方法及网络节点设备通 过保证流量切换过程中各事件的处理顺序， 保证流量切换过程中流量的 稳定， 防止流量出现中断。
附图简要说明
图 1为 MPLS网络协议标签路径示意图。
图 2为本发明一实施例的 MPLS网络流量切换流程图。
图 3为图 2中步骤 S202的细化流程图。
图 4为图 2中步骤 S203的细化流程图。 图 5为图 2中步骤 S204的细化流程图。
图 6为本发明一实施例的网络节点设备的结构框图。
实施本发明的方式
参阅图 1 , 路径 A-B-C-D-E为一多协议标签交换网络的标签交换路 径（ LSP, Label Switching Path )。 路径 A-G-C用来对节点 B及其相关链 路进行保护， 路径 B-G-D用来对节点 C及其相关链路进行保护， 路径 C-F-E用来对节点 D及其相关链路进行保护， 路径 D-F-E用来对链路 D-E进行保护。 如果 B-C段的链路发生故障， 节点 B上的流量可以立即 切换到 B-G-D路径上， 避免报文的丟失。 快速重路由作为一种临时的保 护方式， 发生链路故障后， 主隧道会立即触发创建一条新的标签交换路 径。 新的标签交换路径建立成功后， 会将流量切换到新建的标签交换路 径上。
在多协议标签交换网络的标签交换路径建立以后， 用户修改 MPLS 流量工程隧道属性或者在快速重路由发生流量切换时， 网络会触发建立 新的标签交换路径并将流量切换到新的标签交换路径上。 参阅图 2, 本 实施例提供一种多协议标签交换网络流量切换的方法。 当某一标记交换 路径 LSP 的入口节点收到表示新的标签交换路径创建成功的资源预留 消息 （RESV, Resource Reservation ) (步骤 S201 ), 则生成新的上行及 下行转发表， 所述新的标签交换路径创建成功的消息记录了流量工程所 需的各种信息， 如会话序号、 标记对象、 资源与流对象路径记录等。 然 骤 S202 )给转发单元， 所述新下行转发表转发完成后， 当该节点配置新 下行转发表后， 该入口节点的网络节点设备的控制平面发送所述保存的 新上行转发表（步骤 S203 ), 转发单元按新的转发表对数据进行转发， 这样实现流量切换， 流量切换成功后删除转发单元中切换前的旧转发表 (步骤 S204 )。
以图 1所示的多协议标签交换网络为例， 多协议标签交换网络的标 签交换路径 A-B-C-D-E切换为标签交换路径 A-G-C-D-E。 当入口节点 A 接收到新的标记交换路径 A-G-C-D-E 创建成功的消息 （Resource Reservation ) 时， 产生新的上行及下行转发表。 节点 A的控制平面将上 行转发表入标签映射（ILM表项）保存起来， 例如保存在其控制平面内 或一存储单元， 其控制平面发送下行转发表下一跳标记转发入口 ( NHLFE表项）。 当转发表更新为新的 ILM表项和 NHLFE表项后流量 切换成功， 控制平面删除切换前的隧道 A-B-C-D-E, 此时流量主隧道为 隧道 A-G-C-D-E。
为了保证各事件的处理顺序， 本发明 MPLS网络流量切换的方法第 一实施例引入定时器来保证所述流量切换过程中各事件的处理顺序。 参 阅图 3, 步骤 S202的细化流程图。在标签交换路径的入口节点接收到新 的标签交换路径创建成功消息的同时启动一路径删除定时器 （步骤 S301 ), 然后控制平面保存新上行转发表 ILM (步骤 S302 )和发送新下 行转发表 NHLFE(步骤 S303 ) ,步骤 S302和步骤 S303也可以同时进行。 当控制平面发送新下行转发表 NHLFE后启动一流量切换定时器（步骤 S304 )。 参阅图 4, 步骤 S203的细化流程图， 当所述流量切换定时器超 时后控制平面发送上行转发表 ILM。参阅图 5,步骤 S204的细化流程图， 当所述删除路径定时器超时后删除切换前旧转发表。
新的标签交换路径创建成功事件触发启动所述路径删除定时器， 控 制平面发送新下行转发表事件触发启动所述流量切换定时器。 用户可以 自行更改对所述定时器延时时间进行配置， 路径删除定时器的到达超时 的时间大于流量切换定时器。
仍以图 1所示的 MPLS网络为例，在入口节点 A接收到新的标签交 换路径创建成功消息的同时启动路径删除定时器，然后节点 A的控制平 面将新上行转发表 ILM 保存起来， 同时控制平面发送新下行转发表 NHLFE但不替换切换前的下行转发表 NHLFE。此时在入口节点 A的上 行信息为切换前上行转发表 ILM ,下行信息中切换前下行转发表 NHLFE 和新下行转发表 NHLFE共存， 即路径 A-B-C-D-E和路径 A-G-C-D-E的 下行转发表 NHLFE在 A节点共存。入口节点 A的控制平面发送下行转 发表 NHLFE后启动流量切换定时器。 所述新下行转发表转发完成后控 制平面发送该节点的上行转发表 ILM,新上行转发表 ILM替换切换前的 上行转发表 ILM ,此时在入口节点 A的上行信息中为新上行转发表 ILM , 但路径 A-B-C-D-E和路径 A-G-C-D-E的下行转发表 NHLFE仍在 A节点 共存。 路径删除定时器超时后控制平面删除切换前的标签交换路径， 即 删除路径 A-B-C-D-E及相关表项， 此时节点 A切换前的下行转发表 NHLFE被节点控制平面删除， 只存有新下行转发表 ILM和下行转发表 NHLFE, 流量完全切换到新的标签交换路径 A-G-C-D-E。 所述协议交换 路径为一般协议交换路径， 也可以具体为基于约束的协议交换路径。 当 交换路径为基于约束的协议交换路径时流量切换的步骤和方法仍如前 所述。
采用所述多协议标签交换网络流量切换的方法， 在标签交换路径的 入口节点 A收到信的标签交换路径创建成功的消息后，立即发送新的下 行转发表 NHLFE, 但并不发送新上行转发表 ILM, 只是将新上行转发 表 ILM保存起来， 启动流量切换定时器， 该定时器超时时才发送新上行 转发表 ILM。切换前的标签交换路径 A-B-C-D-E也不会立即被删除。 若 路径删除定时器超时， 则触发删除切换前的标签交换路径 A-B-C-D-E。 流量切换定时器和路径删除定时器可以设定默认值， 也可配置， 通过这 两个定时器来保证： 头节点 A切换流量时， 所有的下游节点都已经发送 了新的转发表； 在新上行转发表 ILM表项没有发送前， 旧下行转发表 NHLFE表项会一直存在。 本发明实施例的流量切换方法通过定时器来 保证流量切换过程中各事件的处理顺序， 并通过新旧转发表短时间共存 的方式来进行緩沖， 降低流量切换过程中流量中断情况出现的可能。
为了保证各事件的处理顺序， 本发明 MPLS网络流量切换的方法第 表。 与第一实施例不同在于， 本第二实施例无需设置路径删除定时器。 在标签交换路径的入口节点接收到新的标签交换路径创建成功消息生 成新的上行转发表及下行转发表， 先发送新下行转发表， 入口节点的转 发单元接收到所述新下行转发表后生成一个反馈消息， 并将该反馈消息 回送至控制平面。 控制平面接收到该反馈消息认为新下行转发表发送完 成， 然后控制平面发送新上行转发表。 采用所述多协议标签交换网络流 量切换的方法，在标签交换路径的入口节点 A收到信的标签交换路径创 建成功的消息后， 立即发送新的下行转发表 NHLFE, 但并不发送新上 行转发表 ILM,只是将新上行转发表 ILM保存起来，新下行转发表转发 完成后才发送新上行转发表 ILM。 采用上述方法可以达到第一实施例同 样的效果。
本发明的实施例还提供一种网络节点设备， 参阅图 6, 所述网络节 点设备的结构框图。 本实施例提供的网络节点设备 10 包括： 一信令接 收单元 101、 定时器单元 102、 一控制平面 104、 一转发单元 105及一数 据接收单元 106。
所述控制平面 104分别与数据接收单元 106、 信令接收单元 101、 定时器单元 102及转发单元 105连接并对其进行控制， 实现所述各单元 的通信。该转发单元 105还包括一反馈消息生成单元，所述转发单元 105 接收到控制平面发送的转发表后生成反馈消息， 告知控制平面 104该转 发单元 105接收到了其发送的转发表。 该控制平面 104包括一转发表生 成单元 1041 , 当其收到新的标签交换路径创建成功消息时产生新的上行 及下行转发表； 一转发表发送单元 1042, 用于接收新下行转发表， 并在 第一时刻将下行转发表发送给转发单元， 并在第二时刻时， 接收新上行 转发表， 并将上行转发表发送给转发单元。 此外所述控制平面 104还进 一步负责标签的分配、 转发表的建立及发送、 标签交换路径的删除等任 务。 该网络节点设备还可以进一步包括一存储单元 103, 控制平面 104 建立的转发表在不立即发送时， 将其暂存在所述存储单元 103中。 作为 另一种实施方式， 存储单元 103可设置在控制平面 104中。
所述信令接收单元 101用于接收网络中的信令、 消息等， 例如标签 交换路径创建成功的消息。 所述数据接收单元 106, 其用于接收在网络 中传输的数据包。 所述定时器单元 102用于设置和启动超时定时器。 该 定时器单元 102包括流量切换定时器 1021、 路径删除定时器 1022。 所 述信令接收单元 101接收到标签交换路径创建成功的消息触发启动路径 删除定时器 1022;所述控制平面 104发送转发表时可以触发所述流量切 换定时器 1021。所述定时器均为超时定时器。所述流量切换定时器 1021 超时后触发所述控制平面 104发送暂存在控制平面 104 中或存储单元 103中的转发表。 所述转发单元 105根据控制平面发送的转发表将数据 接收单元 1012接收的数据包转发出去。
在进行网络流量切换时， 如果该网络节点设备是一标签交换路径的 入口节点， 当其信令接收单元 101接收标签交换路径创建成功的消息时 控制平面 104建立新的转发表， 并根据需要将转发表发送或暂存起来。 信令接收单元 101接收标签交换路径创建成功的同时触发启动定时器单 元 102中的路径删除定时器 1022。 控制平面 104在发送转发表时（第一 时刻）触发启动流量切换定时器 1021 ,该流量切换定时器 1021超时（第 二时刻）后控制平面发送暂存在控制平面 104中或存储单元 103中的转 发表。 路径删除定时器 1022超时后控制平面将切换前的转发表删除。 转发单元 105 根据转发表将将数据接收单元 106接收的数据包转发出 去。 至此该网络节点设备完成流量的切换， 并能降低在流量切换过程中 流量出现中断的可能。
作为标签交换路径的入口节点另一实施例， 可省去所述的流量切换 定时器 1021 , 而在转发单元 105中包括一反馈消息生成单元， 转发表产 生单元 1041在生成转发表后， 转发表发送单元 1042即发送新下行转发 表（第一时刻） 至转发单元 105 , 转发单元 105接收到所述新上行转发 表后所述反馈消息生成单元产生反馈消息给信令接收单元 101 , 信令接 收单元 101接收到该反馈消息后（第二时刻）控制平面控制发送单元 1042 即发送新上行转发表。
在进行网络流量切换时， 如果该节点设备不是标签交换路径的入口 节点， 则不需接收交换路径创建成功的消息。 控制平面 104根据路由信 息建立新的转发表， 并根据需要将所述转发表发送或暂存起来。 控制平 面 104在发送转发表时触发启动流量切换定时器 1021 ,该流量切换定时 器 1021超时后， 控制平面发送暂存在控制平面 104 中或存储单元 103 中的转发表。 路径删除定时器 1022超时后控制平面将切换前的转发表 删除。 转发单元 105根据转发表将将数据接受单元 1012接收的数据包 转发出去。 至此该网络节点设备完成流量的切换， 并能降低在流量切换 过程中流量出现中断的可能。

Claims

权利要求书
1. 一种多协议标签交换网络流量切换的方法， 其特征在于， 所述方 法包括：
接收标签交换路径建立成功的消息，
根据所述标签交换路径建立成功的消息生成上行转发表和下行转发 表；
将所述下行转发表发送至转发单元；
所述下行转发表转发完成后将所述上行转发表发送至转发单元； 转发单元根据所述上行转发表和所述下行转发表进行流量转发。
2. 如权利要求 1所述的多协议标签交换网络流量切换的方法，其特 征在于， 所述下行转发表转发完成后将所述上行转发表发送至转发单元 的步骤为：
发送下行转发表时启动一流量切换定时器， 若所述流量切换定时器 超时， 则发送新上行转发表。
3. 如权利要求 1所述的多协议标签交换网络流量切换的方法，其特 征在于， 所述下行转发表转发完成后将所述新上行转发表发送至转发单 元的步骤具体为：
获得所述下行转发表发送完成的消息；
发送所述上行转发表。
4. 如权利要求 3所述的多协议标签交换网络流量切换的方法，其特 征在于， 获得所述下行转发表转发完成的消息具体为：
转发单元获得所述下行转发表后产生一反馈消息， 并将该消息传送 至控制单元。
5. 如权利要求 1所述的多协议标签交换网络流量切换的方法，其特 征在于， 将所述下行转发表发送至转发单元的步骤包括：
将所述下行转发表发送至转发单元并保留转发单元中切换前的旧下 行转发表。
6. 如权利要求 5所述的多协议标签交换网络流量切换的方法，其特 征在于， 之后进一步包括：
接收新的标签交换路径建立成功的消息时启动一路径删除定时器； 所述路径删除器超时后删除切换前旧下行转发表。
7.如权利要求 5所述的多协议标签交换网络流量切换的方法， 其特 征在于， 保留转发单元中切换前旧下行转发表具体为：
8. 一种网络节点设备， 其特征在于， 所述设备包括：
数据接收单元， 用于接收来自网络中其它节点的数据；
转发单元， 用于根据转发表对所述数据接收单元所接收的数据进行 转发；
信令接收单元， 用于接收标签路径建立成功的消息；
转发表生成单元， 用于根据所述标签路径建立成功的消息生成转发 表， 所述转发表包括上行转发表和下行转发表；
转发表发送单元， 用于在第一时刻将所述转发表生成单元所生成的 下行转发表发送给转发单元， 并在第二时刻将所述转发表生成单元所生 成的上行转发表发送给转发单元。
9. 如权利要求 8所述的网络节点设备， 其特征在于， 所述设备还包 括：
流量切换定时器， 用于计时， 在转发表发送单元将所述转发表生成 单元所生成的下行转发表发送给转发单元时， 启动所述流量切换定时 器； 流量切换定时器超时， 则转发表发送单元将所述转发表生成单元所 生成的上行转发表发送给转发单元。
10. 如权利要求 8所述的网络节点设备， 其特征在于， 所述转发单 元还包括一反馈消息生成单元， 用于所述转发单元获得下行转发表后， 生成反馈消息并发送给信令接收单元， 信令接收单元根据所述反馈消息 确定第二时刻。
11.如权利要求 8所述的网络节点设备， 其特征在于， 还包括： 路径删除定时器， 所述转发表发送单元发送转发表时启动该流量切 换定时器；
删除单元， 在所述路径删除定时器超时时， 删除转发单元中的旧下 行转发表。
12. 如权利要求 8所述的网络节点设备， 其特征在于， 还包括： 存储单元， 用于存储转发表生成单元所生成的新上行转发表。
13.如权利要求 6所述网络节点设备， 其特征在于， 所述转发表生成 单元还包括：
存储单元， 用于存储新上行转发表。
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US20120163387A1 (en) 2012-06-28
CN100583827C (zh) 2010-01-20
EP2099174A4 (en) 2009-12-30
CN101060483A (zh) 2007-10-24
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US8155124B2 (en) 2012-04-10
US20100054265A1 (en) 2010-03-04

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