技术领域technical field
本发明实施例涉及移动通信技术领域，具体涉及一种TD-LTE城域回传网络、路径保护方法。The embodiment of the present invention relates to the technical field of mobile communication, and in particular to a TD-LTE metropolitan backhaul network and a path protection method.
背景技术Background technique
现有LTE回传网是基于PTN建设的，TD-LTE传送网组网结构和流量模型如图1所示，基站业务通过接入PTN进入城域PTN网络，经过L2/L3汇聚核心节点至城域L3核心节点，然后经省干PTN系统的L3VPN传送至核心网的MME和SGW。正常情况，所有LTE业务流量、网管流量主用均由地市综合楼L3-1到地市综合楼省干L3-1长距离回传至省会调度L3-1设备，最终回传至EPC核心网。The existing LTE backhaul network is built on the basis of PTN. The network structure and traffic model of the TD-LTE transport network are shown in Figure 1. The base station services enter the metropolitan PTN network through access to the PTN, and converge core nodes to the metropolitan area through L2/L3. Domain L3 core node, and then transmit to the MME and SGW of the core network through the L3VPN of the provincial backbone PTN system. Under normal circumstances, all LTE business traffic and main network management traffic are backhauled from L3-1 of the prefectural comprehensive building to the provincial backbone L3-1 of the prefectural and municipal comprehensive building to the provincial capital dispatching L3-1 equipment, and finally backhauled to the EPC core network .
无线业务通过接入PTN至汇聚核心PTN之间部署MC-PW APS承载保护，双归到汇聚核心L2/L3设备节点。主/备汇聚核心PTN节点通过L2VE终结2层，并通过L3VE入静态城域L3VPN。本地网LTE PTN核心层及省干层实现L3的功能，本地网核心层L2/L3设备和L3设备组成“口字形”结构，实现L3VPN网络，进行L3转发。省干与地市的L3VPN则采用Native IP方式连接。城域传送网核心层L3VPN层面的保护通过隧道Tunnel 1:1与VPN FRR(Fast ReRoute，快速重路由)实现，Tunnel APS用于保护节点之间的隧道路径，VPN FRR用于保护L3VPN网络内部链路和设备节点故障。而省干与地市的L3VPN之间，以及L3 PTN设备与EPC的Native IP业务对接保护方式均为IP、VPN混合FRR保护。The wireless service deploys MC-PW APS bearer protection between the access PTN and the aggregation core PTN, and is dual-homed to the aggregation core L2/L3 equipment node. The active/standby aggregation core PTN node terminates Layer 2 through L2VE, and enters the static metropolitan area L3VPN through L3VE. The LTE PTN core layer and provincial trunk layer of the local network realize the L3 function, and the L2/L3 equipment and the L3 equipment of the local network core layer form a "Zigzag" structure to realize the L3VPN network and perform L3 forwarding. The L3VPNs in provinces and prefecture-level cities are connected through Native IP. The protection at the L3VPN level of the core layer of the metro transport network is realized through the tunnel Tunnel 1:1 and VPN FRR (Fast ReRoute, fast rerouting). Tunnel APS is used to protect the tunnel path between nodes, and VPN FRR is used to protect the internal links of the L3VPN network Road and device nodes are faulty. The connection protection mode between L3VPN between provinces and prefecture-level cities, and between L3 PTN equipment and EPC's Native IP service is IP and VPN hybrid FRR protection.
城域传送网LTE PTN核心层网元(L2/L3设备节点和L3设备节点)均为PE层次网元，PE间采用静态L3VPN组网，形成静态的L3VPN邻居关系，PTN网络L3VPN采用主备方式将LTE的S1接口流量承载在路径较短PE间邻居上。当PE设备检测到主用平面邻居中断时，通过VPNFRR路由快速收敛将流量切换到另一个备用平面的L3VPN邻居上承载，从而实现对其承载业务的保护。The LTE PTN core layer network elements (L2/L3 equipment nodes and L3 equipment nodes) of the metro transport network are all PE-level network elements, and static L3VPN networking is adopted between PEs to form a static L3VPN neighbor relationship. The LTE S1 interface traffic is carried on the neighbors between PEs with shorter paths. When the PE device detects that the neighbor on the active plane is interrupted, it will switch the traffic to another L3VPN neighbor on the standby plane through fast VPNFRR route convergence, so as to protect its bearer services.
经调研多个省份2015年的TD-LTE故障情况，因传输本地网核心层故障引起LTE基站阻断的重大故障有多起，涉及多个地市城域网、多个厂家设备，平均历时超过1个小时，这对网络的稳定运行构成了隐患，迫切需要通过城域传送网优化法进行优化，以实现对LTE业务的保护。After investigating the TD-LTE failure situation in several provinces in 2015, there were many major failures caused by the failure of the core layer of the transmission local network that caused the interruption of the LTE base station, involving the metropolitan area network of many cities and the equipment of multiple manufacturers, with an average duration of more than 1 hour, which poses a hidden danger to the stable operation of the network, and it is urgent to optimize it through the metropolitan area transmission network optimization method to realize the protection of LTE services.
然而，在实现本发明实施例的过程中发明人发现，L2/L3桥接设备与L3设备之间形成口字型组网。两台L2/L3桥接设备与主备L3设备之间均只部署一条10GE链路。现网部署的传统静态L3VPN组网能够实现PTN网络内任一链路或网元单点故障的业务保护。但多点同时故障等复杂场景下的网络保护能力不足，网络健壮性差，存在地市LTE业务将全阻的隐患。具体分析如下：However, during the process of implementing the embodiments of the present invention, the inventors found that a word-of-mouth network is formed between the L2/L3 bridge device and the L3 device. Only one 10GE link is deployed between the two L2/L3 bridge devices and the active and standby L3 devices. The traditional static L3VPN networking deployed on the live network can realize service protection against single point failures of any link or network element in the PTN network. However, the network protection capability is insufficient in complex scenarios such as multi-point simultaneous failures, and the network robustness is poor, and there is a hidden danger that LTE services in cities will be completely blocked. The specific analysis is as follows:
图2为城域传送网LTE PTN核心层的典型组网结构图，将PTN网元之间链路和网元设备分别以数字1至12进行编号。Figure 2 is a typical network structure diagram of the LTE PTN core layer of the metro transport network. Links between PTN network elements and network element equipment are numbered with numbers 1 to 12, respectively.
下面以两点同时故障的场景进行分析，如下14种场景会造成业务阻断，即会引起城域传送网承载的地市eNodeB基站到EPC核心网的S1接口业务阻断。The following is an analysis of two simultaneous failure scenarios. The following 14 scenarios will cause service interruption, that is, the service interruption of the S1 interface between the eNodeB base station in the city carried by the metro transport network and the EPC core network.
表1 14种业务阻断场景Table 1 14 service interruption scenarios
依据表1的统计分析，上述14种场景均会导致PE网元主备L3VPN邻居Peer中断，PTN网络承载的LTE业务阻断。现网的组网模式和保护方法的局限性导致了静态L3VPN组网存在上述的问题，且受限于PTN网元性能，城域网PTN网元不具备动态路由组网能力。According to the statistical analysis in Table 1, the above 14 scenarios will lead to the interruption of the active and standby L3VPN neighbor peers of the PE network element, and the interruption of the LTE service carried by the PTN network. The limitation of the networking mode and protection method of the existing network leads to the above-mentioned problems in the static L3VPN networking, and is limited by the performance of the PTN network element, and the PTN network element of the metropolitan area network does not have the dynamic routing networking capability.
发明内容Contents of the invention
本发明实施例提供了一种TD-LTE城域回传网络、路径保护方法，用以克服现有的组网模式在链路或网元设备存在两处同时故障时会导致全网阻断的缺陷。The embodiment of the present invention provides a TD-LTE metro backhaul network and a path protection method to overcome the problem that the existing network mode will cause the entire network to be blocked when there are two simultaneous faults in the link or network element equipment. defect.
第一方面，本发明提供了一种TD-LTE城域回传网络，包括：由主用L2/L3桥接设备节点、备用L2/L3桥接设备节点、主用L3设备节点以及备用L3设备节点组成的口字型组网；In the first aspect, the present invention provides a TD-LTE metro backhaul network, including: consisting of an active L2/L3 bridge device node, a backup L2/L3 bridge device node, an active L3 device node and a backup L3 device node The mouth-shaped network;
其中，所述口字型组网中的任意两个节点之间均配置有隧道链路组，每个隧道链路组中包含多条隧道链路；每个隧道链路组源、宿只配置一条路由，并将流量分担至组内的若干条隧道链路中传输至另一节点；Wherein, a tunnel link group is configured between any two nodes in the word-shaped network, and each tunnel link group contains multiple tunnel links; each tunnel link group source and destination are only configured One route, and distribute the traffic to several tunnel links in the group for transmission to another node;
所述口字型组网中的主用L2/L3桥接设备节点以及备用L2/L3桥接设备节点之间还配置有四点环网，所述四点环网被配置为直接连接主用L2/L3桥接设备节点、备用L2/L3桥接设备节点、主用L3设备节点、备用L3设备节点；主用L2/L3桥接设备节点与备用L2/L3桥接设备节点之间配置有隧道保护组，其中隧道的工作路径绑定上述四点环网，隧道的环网路径为由主用L2/L3桥接设备节点开始，途径所述主用L3设备节点以及备用L3设备节点，最终到达备用L2/L3桥接设备节点的路径；A four-point ring network is also configured between the main L2/L3 bridging device node and the standby L2/L3 bridging device node in the word-shaped network, and the four-point ring network is configured to directly connect the main L2/L3 bridging device node. L3 bridge device node, backup L2/L3 bridge device node, active L3 device node, and backup L3 device node; a tunnel protection group is configured between the active L2/L3 bridge device node and the backup L2/L3 bridge device node. The working path of the tunnel is bound to the above four-point ring network. The ring network path of the tunnel starts from the active L2/L3 bridge device node, passes through the active L3 device node and the backup L3 device node, and finally reaches the backup L2/L3 bridge device the path of the node;
所述口字型组网中的相邻两个节点之间通过两条物理链路配置有两点环网，所述两点环网被配置为包括两个方向相反的环路，在环路其中一个方向故障时，通过环路另一个方向传输流量。A two-point ring network is configured between two adjacent nodes in the mouth-shaped network through two physical links, and the two-point ring network is configured to include two loops in opposite directions. When one of the directions fails, traffic is transmitted in the other direction of the ring.
可选地，每个隧道链路组包含的隧道链路数满足所述隧道链路组连接的两个节点的流量传输的带宽需求。Optionally, the number of tunnel links included in each tunnel link group meets the bandwidth requirement of traffic transmission between two nodes connected by the tunnel link group.
可选地，每个隧道链路组中用于分担并传输流量的激活隧道链路数大于或等于该隧道链路组中包含的隧道链路数的一半。Optionally, the number of activated tunnel links used to share and transmit traffic in each tunnel link group is greater than or equal to half of the number of tunnel links included in the tunnel link group.
可选地，每个隧道链路组中除所述激活隧道链路以外的隧道链路被配置为保护链路，所述保护链路在所述激活隧道链路发生故障时，继续分担并传输所述激活隧道链路要传输的流量。Optionally, the tunnel links other than the activated tunnel link in each tunnel link group are configured as protection links, and the protection link continues to share and transmit when the activated tunnel link fails. The traffic to be transmitted by the activated tunnel link.
可选地，所述主用L3设备节点、备用L3设备节点分别与省干主用L3设备节点和省干备用L3设备节点之间配置有聚合链路；所述主用L3设备节点、备用L3设备节点的聚合链路的最小活动链路数被配置为非对称值。Optionally, an aggregation link is configured between the active L3 device node and the backup L3 device node and the main L3 device node and the backup L3 device node of the provincial trunk; the active L3 device node, backup L3 The minimum number of active links of the aggregated links of the device node is configured as an asymmetric value.
可选地，所述主用L3设备节点的聚合链路的最小活动链路数为总物理链路成员数，备用L3设备节点的聚合链路的最小活动链路数为总物理链路成员数的一半。Optionally, the minimum number of active links of the aggregated links of the active L3 device node is the total number of physical link members, and the minimum number of active links of the aggregated links of the standby L3 device node is the total number of physical link members half of.
可选地，所述的主、备L2/L3桥接设备节点、主用L3设备节点以及备用L3设备节点中的各个节点被配置为设置的上联端口、互联端口、下联端口不存在于同一块单板上。Optionally, each node in the active and standby L2/L3 bridge device nodes, the active L3 device node and the standby L3 device node is configured so that the set uplink port, interconnection port, and downlink port do not exist in the same block veneer.
第二方面，本发明还提供了一种路径保护方法，应用于上述所述的TD-LTE城域回传网络中，包括：In the second aspect, the present invention also provides a path protection method, which is applied to the above-mentioned TD-LTE metro backhaul network, including:
在所述口字型组网中的任意两个节点之间进行流量传输时，将待传输的流量分担至组内的若干条隧道链路中传输；When performing traffic transmission between any two nodes in the zigzag network, distribute the traffic to be transmitted to several tunnel links in the group for transmission;
在口字型组网中的直接连接主用L2/L3桥接设备节点以及备用L2/L3桥接设备节点的四点环网的工作路径发生故障时，通过所述四点环网的环网路径传输流量；When the working path of the four-point ring network directly connected to the active L2/L3 bridge device node and the standby L2/L3 bridge device node in the word-shaped network fails, the ring network path transmission through the four-point ring network flow;
在所述口字型组网中的相邻两个节点之间两点环网中，在环路的其中一个方向故障时，通过环路另一个方向传输流量。In the two-point ring network between two adjacent nodes in the word-of-mouth network, when one direction of the ring fails, traffic is transmitted through the other direction of the ring.
可选地，所述将待传输的流量分担至组内的若干条隧道链路中传输，包括：Optionally, said allocating the traffic to be transmitted to several tunnel links in the group for transmission includes:
将待传输的流量分担至组内的N条隧道链路中传输，其中N大于或等于该隧道链路组中包含的隧道链路数的一半。Allocate the traffic to be transmitted to N tunnel links in the group for transmission, where N is greater than or equal to half the number of tunnel links included in the tunnel link group.
可选地，所述方法还包括：Optionally, the method also includes:
在用于分担流量的N条激活隧道链路发生故障时，所述隧道链路组中除所述N条激活隧道链路外的保护链路继续分担并传输所述激活隧道链路要传输的流量。When the N active tunnel links used to share traffic fail, the protection links in the tunnel link group except for the N active tunnel links continue to share and transmit the traffic to be transmitted by the active tunnel links. flow.
本发明实施例提供的TD-LTE城域回传网络中，在由主、备L2/L3桥接设备节点、主用L3设备节点以及备用L3设备节点组成的口字型组网中相邻两个节点之间均配置有隧道链路组，可以分担节点之间的流量传输，实现了带宽扩容；此外，相邻两个节点之间通过两条物理链路配置有两点环网，口字型组网中的主、备L2/L3桥接设备节点之间还配置有四点环网，这些环网的设置使得在其中一些网元或链路发生故障时，可以使用其他备用网元或通过其他保护路径传输至目的节点，避免出现城域网LTE PTN承载的流量阻断的现象，从而有效提高TD-LTE城域回传网络的稳定性。In the TD-LTE metro backhaul network provided by the embodiment of the present invention, in the word-shaped network composed of the active and standby L2/L3 bridge equipment nodes, the active L3 equipment node and the standby L3 equipment node, two adjacent Tunnel link groups are configured between nodes, which can share the traffic transmission between nodes and realize bandwidth expansion; in addition, a two-point ring network is configured between two adjacent nodes through two physical links. A four-point ring network is also configured between the active and standby L2/L3 bridge device nodes in the network. The setting of these ring networks enables other backup network elements to be used or other network elements to be used when some network elements or links fail. The protection path is transmitted to the destination node, avoiding the traffic blocking phenomenon carried by the LTE PTN of the metropolitan area network, thereby effectively improving the stability of the TD-LTE metro backhaul network.
附图说明Description of drawings
通过阅读下文优选实施方式的详细描述，各种其他的优点和益处对于本领域普通技术人员将变得清楚明了。附图仅用于示出优选实施方式的目的，而并不认为是对本发明的限制。而且在整个附图中，用相同的参考符号表示相同的部件。在附图中：Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiment. The drawings are only for the purpose of illustrating a preferred embodiment and are not to be considered as limiting the invention. Also throughout the drawings, the same reference numerals are used to designate the same components. In the attached picture:
图1是现有技术中TD-LTE回传网流量模型；Fig. 1 is a TD-LTE backhaul network traffic model in the prior art;
图2是现有技术中城域传送网LTE PTN核心层的典型组网结构图；FIG. 2 is a typical network structure diagram of the LTE PTN core layer of the metro transport network in the prior art;
图3是现有技术中城域传送网LTE PTN核心层L3VPN Peer间LSP和VPN FRR保护示意图；FIG. 3 is a schematic diagram of LSP and VPN FRR protection between L3VPN peers in the LTE PTN core layer of the metro transport network in the prior art;
图4是本发明提供的城域传送网LTE PTN核心层L3VPN Peer间部署ECMP保护示意图；Fig. 4 is the schematic diagram of deploying ECMP protection between LTE PTN core layer L3VPN Peer provided by the present invention;
图5是本发明提供的两节点间部署环网保护示意图；Fig. 5 is a schematic diagram of ring network protection deployed between two nodes provided by the present invention;
图6是现有技术中的L3VPN核心节点间部署两点环网保护示意图；6 is a schematic diagram of a two-point ring network protection deployed between L3VPN core nodes in the prior art;
图7是本发明提供的ICB部署四点环+LSP 1:1保护；Fig. 7 is the ICB deployment four-point ring+LSP 1:1 protection provided by the present invention;
图8是现有技术中城域PTN与省干PTN的L3VPN域间单链路对接示意图；Fig. 8 is a schematic diagram of inter-domain L3VPN single-link interconnection between a metropolitan PTN and a provincial backbone PTN in the prior art;
图9是本发明提供的L3VPN域间部署多链路非对称聚合示意图；FIG. 9 is a schematic diagram of multi-link asymmetric aggregation deployed between L3VPN domains provided by the present invention;
图10是本发明提供的本地网LTE PTN核心层部署多对L2/L3示意图；Fig. 10 is a schematic diagram of deploying multiple pairs of L2/L3 in the LTE PTN core layer of the local network provided by the present invention;
图11是本发明提供的城域传送网LTE PTN核心层312优化方法网络倒换测试拓扑示意图；FIG. 11 is a schematic diagram of a network switching test topology of a metro transport network LTE PTN core layer 312 optimization method provided by the present invention;
图12是本发明提供的城域传送网LTE PTN核心层312优化方法网络倒换流程图。FIG. 12 is a flow chart of network switching in the method for optimizing the LTE PTN core layer 312 of the metro transport network provided by the present invention.
具体实施方式Detailed ways
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.
第一方面，本发明实施例提供了一种TD-LTE城域回传网络，如图3、图6以及图7所示，包括：由主用L2/L3桥接设备节点、备用L2/L3桥接设备节点、主用L3设备节点以及备用L3设备节点组成的口字型组网；In the first aspect, the embodiment of the present invention provides a TD-LTE metro backhaul network, as shown in FIG. 3, FIG. 6 and FIG. A word-shaped network composed of device nodes, active L3 device nodes, and backup L3 device nodes;
其中，口字型组网中的任意两个节点之间均配置有隧道链路组，每个隧道链路组中包含多条隧道链路；每个隧道链路组源、宿只配置一条路由，并将流量分担至组内的若干条隧道链路中传输至另一节点；Among them, a tunnel link group is configured between any two nodes in the word-shaped network, and each tunnel link group contains multiple tunnel links; each tunnel link group source and destination are only configured with one route , and distribute the traffic to several tunnel links in the group for transmission to another node;
口字型组网中的两个主、备L2/L3桥接设备节点之间还配置有四点环网，四点环网被配置为直接连接主用L2/L3桥接设备节点、备用L2/L3桥接设备节点、主用L3设备节点、备用L3设备节点；主用L2/L3桥接设备节点与备用L2/L3桥接设备节点之间配置隧道保护组，其中隧道的工作路径绑定上述四点环网，由其中主用L2/L3桥接设备节点开始，途径主用L3设备节点以及备用L3设备节点，最终到达备用L2/L3桥接设备节点的环网路径；A four-point ring network is also configured between the two active and standby L2/L3 bridge device nodes in the mouth-shaped network. The four-point ring network is configured to directly connect the active L2/L3 bridge device node and the standby L2/L3 Bridge device node, active L3 device node, and backup L3 device node; configure a tunnel protection group between the active L2/L3 bridge device node and the backup L2/L3 bridge device node, where the working path of the tunnel is bound to the above four-point ring network , starting from the active L2/L3 bridge device node, passing through the active L3 device node and the backup L3 device node, and finally reaching the ring network path of the backup L2/L3 bridge device node;
口字型组网中的相邻两个节点之间通过两条物理链路配置有两点环网，所述两点环网被配置为包括两个方向相反的环路，在环路其中一个方向故障时，通过环路另一个方向传输流量。A two-point ring network is configured between two adjacent nodes in the word-shaped network through two physical links, and the two-point ring network is configured to include two rings with opposite directions, and one of the rings is In case of a direction failure, traffic is transmitted in the other direction of the ring.
本发明实施例提供的TD-LTE城域回传网络中，在由主、备L2/L3桥接设备节点、主用L3设备节点以及备用L3设备节点组成的口字型组网中相邻两个节点之间均配置有隧道链路组，可以分担节点之间的流量传输，实现了带宽扩容；此外，相邻两个节点之间通过两条物理链路配置有两点环网，口字型组网中的相邻两个主、备L2/L3桥接设备节点之间还配置有四点环网，这些环网的设置使得在其中一些网元或链路发生故障时，可以使用其他备用网元或通过其他保护路径传输至目的节点，避免出现城域网LTE PTN承载的流量阻断的现象，从而有效提高TD-LTE城域回传网络的稳定性。In the TD-LTE metro backhaul network provided by the embodiment of the present invention, in the word-shaped network composed of the active and standby L2/L3 bridge equipment nodes, the active L3 equipment node and the standby L3 equipment node, two adjacent Tunnel link groups are configured between nodes, which can share the traffic transmission between nodes and realize bandwidth expansion; in addition, a two-point ring network is configured between two adjacent nodes through two physical links. There is also a four-point ring network configured between the two adjacent active and standby L2/L3 bridge device nodes in the network. The settings of these ring networks enable other backup networks to be used when some network elements or links fail. It can be transmitted to the destination node through other protection paths, so as to avoid the phenomenon of blocking traffic carried by the LTE PTN of the metropolitan area network, thereby effectively improving the stability of the TD-LTE metro backhaul network.
上述方法可以概括为3个部署，除此之外，为了进一步提高网络的安全稳定性，本发明实施例还提出了1个聚合以及2个原则，下面对本发明实施例提出的3个部署、1个聚合以及2个原则进行详细说明。The above method can be summarized into three deployments. In addition, in order to further improve the security and stability of the network, the embodiment of the present invention also proposes 1 aggregation and 2 principles. The following describes the 3 deployments, 1 Aggregation and two principles are described in detail.
1、3个部署，也即城域传送网LTE PTN核心层的保护的补充方法1. Three deployments, that is, a supplementary method for the protection of the LTE PTN core layer of the metro transport network
城域传送网LTE PTN核心层的保护的补充方法是在现网保护方案的基础上增加的补充完善方法。补充方法能够满足高可靠性、带宽大于等于原有PTN网络链路带宽、业务能够安全隔离等特点，与现有PTN非共传输系统、可开启MPLS L3功能的IP网络、端到端时延和PTN现网相当。综上提出了补充保护方法，包括L3VPN Peer间部署ECMP(等价多路径)，L3VPN核心节点间部署两点环网和ICB(同步协议通道)部署四点环网+LSP 1:1保护方法。The supplementary method for the protection of the LTE PTN core layer of the metro transport network is a supplementary and perfect method added on the basis of the existing network protection scheme. The supplementary method can meet the characteristics of high reliability, bandwidth greater than or equal to the link bandwidth of the original PTN network, and secure isolation of services. The current network of PTN is equivalent. In summary, a supplementary protection method is proposed, including deploying ECMP (equal-cost multipath) between L3VPN peers, deploying a two-point ring network between L3VPN core nodes, and deploying a four-point ring network + LSP 1:1 protection method with ICB (synchronous protocol channel).
1.1、L3VPN Peer间部署ECMP1.1. Deploy ECMP between L3VPN peers
(1)现网L3VPN Peer间部署的相关保护(1) Related protections deployed between L3VPN peers on the live network
城域L3VPN网络通常采用口字型组网，有多对L2/L3设备可以拆分为多个口字型网络的叠加。The metro L3VPN network usually adopts a zigzag network, and multiple pairs of L2/L3 devices can be split into a superposition of multiple zigzag networks.
L2/L3节点与L3节点，L3节点间形成VPN PEER关系(如图3段状虚线所示)，现网PEER间物理链路数通常1条，PEER节点通过隧道收发数据，隧道LSP 1:1线性保护(如图3点状虚线所示)，PEER的工作路径走最短路径，另一个方向为保护路径。L2/L3 nodes and L3 nodes form a VPN PEER relationship between L3 nodes (as shown by the dotted line in Figure 3). The number of physical links between PEERs in the current network is usually 1. PEER nodes send and receive data through tunnels, and the tunnel LSP is 1:1. For linear protection (as shown by the dotted line in Figure 3), the working path of PEER takes the shortest path, and the other direction is the protection path.
PTN城域网L3VPN的VPN Peer间仅使用一条带LSP 1:1tunnel，即使某些地市在物理连接上部署了多条物理链路，但运行传统的路由协议只能利用其中一条链路传送数据包，该链路容易拥塞，其它链路处于备份状态或无效状态，链路资源空闲浪费，且安全性比较低。Only one LSP 1:1 tunnel is used between VPN peers of PTN MAN L3VPN. Even if multiple physical links are deployed on physical connections in some cities, traditional routing protocols can only use one of the links to transmit data. Packets, the link is prone to congestion, other links are in the backup state or invalid state, the link resources are idle and wasteful, and the security is relatively low.
(2)312优化法中L3VPN Peer间部署ECMP技术方案(2) ECMP technical solution deployed between L3VPN peers in 312 optimization method
ECMP(Equal-Cost Multipath Routing，等价多路由)技术，将发往同一目的IP或者同一目的网段的三层转发流量通过不同的路径进行分担，实现网络的负载均衡。ECMP (Equal-Cost Multipath Routing, Equal-Cost Multipath Routing) technology shares the three-layer forwarding traffic sent to the same destination IP or the same destination network segment through different paths to achieve network load balancing.
在每个PE节点配置多条隧道，配置成隧道负荷分担组(简称：LSP ECMP组)，再配置一条路由，该路由出口为LSP ECMP组，在LSP转发层面通过HASH算法对业务进行负荷分担，将流量分担到LSP ECMP组的所有可用成员，如图4所示，图4中以“XX综合楼L2/L3-1”为例画出了示意图，“XX综合楼L2/L3-1”的下一跳主用路径由链路3和9捆绑部署ECMP形成的LSPECMP组承载，“XX综合楼L2/L3-1”的下一跳备用路径由链路5和6捆绑、链路4和10捆绑、链路2和8捆部署ECMP形成的LSP ECMP组承载，实现主备路径的ECMP负载分担和保护。Configure multiple tunnels on each PE node, configure them as a tunnel load sharing group (LSP ECMP group for short), and then configure a route. The route egress is an LSP ECMP group. At the LSP forwarding level, the HASH algorithm is used to load balance the business. Distribute the traffic to all available members of the LSP ECMP group, as shown in Figure 4. In Figure 4, "XX Complex Building L2/L3-1" is used as an example to draw a schematic diagram. The "XX Complex Building L2/L3-1" The main path of the next hop is carried by the LSPECMP group formed by bundling and deploying ECMP between links 3 and 9, and the backup path of the next hop of "XX complex building L2/L3-1" is bundled by links 5 and 6, and links 4 and 10 Bundle, link 2, and 8 bundles are deployed with LSP ECMP group bearer formed by ECMP to realize ECMP load sharing and protection of active and standby paths.
城域传送网核心层通常采用华为PTN3900设备(软件V1R5版本)、中兴ZXCTN6500设备(软件V1.00.10R2版本)，核心层L2/L3设备至L3设备、主备L3设备之间仅支持一条10GE或者GE链路对接，为能部署ECMP技术需要对城域网核心层的华为PTN3900设备的软件版本升级为V1R7，需要将中兴ZXCTN6500设备的软件版本升级为V2.00.10版本。The core layer of the metro transport network usually adopts Huawei PTN3900 equipment (software version V1R5) and ZTE ZXCTN6500 equipment (software version V1.00.10R2). Only one 10GE or For GE link interconnection, in order to deploy ECMP technology, the software version of Huawei PTN3900 equipment at the core layer of the metropolitan area network needs to be upgraded to V1R7, and the software version of ZTE ZXCTN6500 equipment needs to be upgraded to version V2.00.10.
■在配置LSP ECMP组后，LSP ECMP组的源、宿只需配置一条路由；■After the LSP ECMP group is configured, only one route needs to be configured for the source and destination of the LSP ECMP group;
■源点PE到两个远端PE点的路由是主备关系，业务路径可通过显示路径配置控制，业务在部分链路上负载均衡，另外部分链路作为保护链路。■The route from the source PE to two remote PEs is an active-standby relationship. The service path can be controlled by displaying path configuration. The service is load-balanced on some links, and some links are used as protection links.
■同一PE节点的两个LSP ECMP对应两条路由，路由之间形成VPN FRR保护，同一个LSP ECMP组中的成员均指向同一个远端PE节点；■Two LSP ECMPs of the same PE node correspond to two routes, and VPN FRR protection is formed between the routes, and members in the same LSP ECMP group all point to the same remote PE node;
■LSP ECMP中可配置最小成员数，最小成员数应能满足PE之间的业务承载带宽需求。比如，假设PE之间带宽需求为15GE，则最小成员数应为2，LSP ECMP总成员数建议为3-4。当LSP ECMP中可用成员数小于最小成员数时，将触发VPN FRR倒换；■The minimum number of members can be configured in LSP ECMP, and the minimum number of members should be able to meet the service bearing bandwidth requirements between PEs. For example, assuming that the bandwidth requirement between PEs is 15GE, the minimum number of members should be 2, and the total number of LSP ECMP members is recommended to be 3-4. When the number of available members in LSP ECMP is less than the minimum number of members, VPN FRR switching will be triggered;
■隧道ECMP组的组属性：最小激活成员数建议设置为成员总数/2，LSP ECMP最大支持16个成员。■Group attributes of the tunnel ECMP group: the minimum number of active members is recommended to be set to the total number of members/2, and LSP ECMP supports a maximum of 16 members.
■在L3设备间、L2/L3设备间、L3设备间与L2/L3设备间各新增1条链路，部署ECMP后，能够抗3次链路故障。■ Add one link between L3 devices, between L2/L3 devices, between L3 devices and between L2/L3 devices. After ECMP is deployed, it can resist three link failures.
此外，随着LTE基站数量的增加，基站带宽需求的增加，核心层的10GE链路不能满足带宽需求，通过VPN Peer间部署ECMP实现N*10GE带宽扩容和多链路的负载分担。In addition, as the number of LTE base stations increases, the bandwidth requirements of the base stations increase, and the 10GE links at the core layer cannot meet the bandwidth requirements. ECMP is deployed between VPN peers to realize N*10GE bandwidth expansion and multi-link load sharing.
1.2、L3VPN核心节点间部署两点环网1.2. Deploy a two-point ring network between L3VPN core nodes
为提高网络安全性，城域网312优化法提出了在L3VPN核心节点间部署两点环网。该优化内容可以作为“VPN Peer间部署ECMP”的补充或者多重保护来部署。现网华为区域PTN3900(V1R5)不支持ECMP，即使部署PEER间部署多条链路也无法承载LTE业务流量来提高安全性，提出了在两点间部署环网保护，或者实现抗3条链路故障，对于其它不能升级为V1R7的网元类型也可以部署该环网保护。In order to improve network security, the MAN 312 optimization method proposes to deploy a two-point ring network between L3VPN core nodes. This optimized content can be deployed as a supplement to "ECMP between VPN peers" or as multiple protections. The current Huawei regional PTN3900 (V1R5) does not support ECMP. Even if multiple links are deployed between PEERs, LTE service traffic cannot be carried to improve security. It is proposed to deploy ring network protection between two points, or to implement anti-three links fault, this ring network protection can also be deployed for other network element types that cannot be upgraded to V1R7.
L3VPN的PEER节点间通过在两条物理链路部署两点环网后，如图5所示。业务正常情况沿着预先制定的信号流走，如图5中上方的信号流，当物理链路Ⅰ故障时，业务倒换至图中物理链路Ⅱ下方信号流，而不引起环上所承载的端到端tunnel，只有2条物理链路均故障，才会发生tunnel 1:1保护倒换。After the two-point ring network is deployed on the two physical links between the PEER nodes of the L3VPN, as shown in Figure 5. The normal service follows the pre-established signal flow, as shown in the upper signal flow in Figure 5. When the physical link I fails, the service is switched to the lower signal flow of the physical link II in the figure, without causing the signal flow carried by the ring. In an end-to-end tunnel, tunnel 1:1 protection switching occurs only when two physical links fail.
城域传送网LTE PTN核心节点间扩容1条链路，与原有在用链路组成两点环网保护，将经过这两个核心节点间的所有tunnel均上环绑定，保护部署位置如图6所示，L2/L3至L3节点间、L3节点间均部署两点环网保护。Expand a link between the LTE PTN core nodes of the metro transport network, and form a two-point ring network protection with the original link in use. All tunnels passing through the two core nodes will be bound on the ring, and the protection deployment location is As shown in Figure 6, two-point ring network protection is deployed between L2/L3 to L3 nodes and between L3 nodes.
环网保护包括互为保护的两个相反方向的环，每个方向都包括工作和保护环通道，通过保护通道提供冗余的带宽，在网络失效或劣化后，分布式业务能够自动恢复。环网是能够自愈的，是独立的逻辑层次，易于管理；基于环网进行倒换，倒换速度快。Ring network protection includes two rings in opposite directions for mutual protection. Each direction includes working and protection ring channels. Redundant bandwidth is provided through the protection channels. After network failure or degradation, distributed services can be automatically restored. The ring network is capable of self-healing and is an independent logical level, which is easy to manage; switching is performed based on the ring network, and the switching speed is fast.
1.3、ICB部署四点环+LSP 1:1保护1.3. ICB deploys four-point ring + LSP 1:1 protection
L2/L3节点间需要建立ICB(同步控制协议通道，通常称为心跳线)，用于承载MC-LAG协议报文、ARP热备表(用于备L2/L3节点从主L2/L3节点同步ARP表项)、BFD协议等。在现网中一旦ICB通道中断，该对L2/L3节点下所带LTE基站业务全部阻断，该情况在2015年发生过多次，造成了多起地市阻断。An ICB (synchronous control protocol channel, usually called a heartbeat line) needs to be established between L2/L3 nodes to carry MC-LAG protocol packets and ARP hot standby tables (used for the backup L2/L3 nodes to synchronize ARP entry), BFD protocol, etc. Once the ICB channel is interrupted in the current network, all LTE base station services under the L2/L3 node will be blocked. This situation happened many times in 2015, resulting in many city blockages.
312优化法提出了ICB部署四点环+LSP 1:1保护方案，如图7所示。即首先在L2/L3节点间部署tunnel 1:1保护，工作路径选择L2/L3节点间直连链路，如图7中链路5，保护路径选择XX综合楼L2/L3-1——XX综合楼L3——XX二枢纽L3——XX二枢纽L2/L3-1——XX综合楼L2/L3-1，然后L2/L3节点间链路5和6部署两点环网保护，将上述工作路径绑定在环网，实现了L2/L3节点的ICB在主备Tunnel上承载时，业务路径实际在三条物理链路承载和保护。The 312 optimization method proposes an ICB deployment four-point ring + LSP 1:1 protection scheme, as shown in Figure 7. That is, first deploy tunnel 1:1 protection between L2/L3 nodes, select the direct link between L2/L3 nodes as the working path, as shown in link 5 in Figure 7, and select XX complex building L2/L3-1——XX as the protection path Comprehensive building L3——XX second hub L3——XX second hub L2/L3-1——XX comprehensive building L2/L3-1, and then deploy two-point ring network protection for links 5 and 6 between L2/L3 nodes, and the above The working path is bound to the ring network, so that when the ICB of the L2/L3 node is carried on the active and standby tunnels, the service path is actually carried and protected by three physical links.
当物理链路5或6故障时，工作路径tunnel首先发生环网保护倒换，不发生tunnel1:1保护倒换。仅当物理链路5和6同时故障时，发生tunnel 1:1保护倒换，倒换到保护路径，实现抗2次故障能力。在配置过程中需要将环网保护倒换拖延时间设置小于tunnel 1:1保护倒换拖延时间，避免二次倒换。When physical link 5 or 6 fails, ring network protection switching occurs first on the working path tunnel, and tunnel1:1 protection switching does not occur. Only when physical links 5 and 6 fail at the same time, tunnel 1:1 protection switching occurs, switching to the protection path, and realizing the capability of resisting two failures. During the configuration process, it is necessary to set the ring network protection switching delay time to be less than the tunnel 1:1 protection switching delay time to avoid secondary switching.
2、1个聚合，也即L3VPN域间部署多链路非对称聚合2. One aggregation, that is, the deployment of multi-link asymmetric aggregation between L3VPN domains
城域PTN与省干PTN的对接是L3VPN域间的对接，采用采用Native IP对接，在核心PTN上配置去往省干PTN的静态路由，并配置IP/VPN混合FRR。The interconnection between the metropolitan PTN and the provincial backbone PTN is the interconnection between L3VPN domains. Native IP is used for interconnection. Static routes to the provincial backbone PTN are configured on the core PTN, and IP/VPN hybrid FRR is configured.
现网中采用单个10GE端口对接，存在安全性低和带宽不足问题。如图8所示。本312优化法提出了1个聚合，即：在省干PTN的L3VPN和城域PTN的L3VPN的VRF在域间部署多链路非对称聚合。In the current network, a single 10GE port is used for interconnection, which has the problems of low security and insufficient bandwidth. As shown in Figure 8. This 312 optimization method proposes one aggregation, that is, the L3VPN of the provincial backbone PTN and the VRF of the L3VPN of the metropolitan area PTN deploy multi-link asymmetric aggregation between domains.
链路聚合技术是将多个物理端口捆绑在一起作为一个逻辑接口(Trunk接口)使用，不仅能提高链路带宽，也能提高网络安全性。聚合组中物理端口称为Trunk的成员。Link aggregation technology bundles multiple physical ports together as a logical interface (Trunk interface), which not only improves link bandwidth, but also improves network security. Physical ports in an aggregation group are called trunk members.
城域传送网312优化法提出的多链路非对称聚合是指城域主、备L3与省干PTN采用ETH-Trunk端口捆绑技术，城域L3设备与同机房地市干线PTN设备通过N*10GE捆绑互联，并将主、备L3的ETH-Trunk最小活动链路数为设置为非对称值。如图9所示。The multi-link asymmetric aggregation proposed by the 312 optimization method of the metropolitan area transmission network refers to the use of ETH-Trunk port bundling technology between the master and backup L3 and the provincial trunk PTN in the metropolitan area. 10GE is bundled and interconnected, and the minimum number of active links of the active and standby L3 ETH-Trunk is set to an asymmetric value. As shown in Figure 9.
多链路非对称聚合经过多次试验，建议主用L3节点ETH-TRUNK UP＝N(即最小活动链路数等于聚合组成员数，N<＝16)，备用L3节点ETH-TRUNK UP＝N/2(即最小活动链路数等于聚合组成员数的一半)。Multi-link asymmetric aggregation After many tests, it is recommended that the active L3 node ETH-TRUNK UP=N (that is, the minimum number of active links is equal to the number of aggregation group members, N<=16), and the backup L3 node ETH-TRUNK UP=N /2 (that is, the minimum number of active links is equal to half the number of members in the aggregation group).
进行报文转发时，如果Trunk接口协议是UP状态，Trunk会利用Hash算法选定一个UP的成员端口作为真正的出接口将报文发送出去。Hash算法可以根据某种方式，如报文的源/目的IP地址，TCP报文逐包，UPD报文逐包等，尽量将流量分担到各个成员口上。而Hash的方式在逻辑口上是可定义。When forwarding packets, if the Trunk interface protocol is in the UP state, the Trunk will use the Hash algorithm to select an UP member port as the real outbound interface to send the packet. The Hash algorithm can be based on a certain method, such as the source/destination IP address of the packet, TCP packets packet-by-packet, UPD packet-by-packet, etc., to try to distribute the traffic to each member port. The way of Hash is definable in terms of logic.
L3VPN域间进行多链路非对称聚合优势：Advantages of multi-link asymmetric aggregation between L3VPN domains:
■主用L3节点ETH-TRUNK UP＝N能够增加原有链路带宽，实现流量的负载分担。■The main L3 node ETH-TRUNK UP=N can increase the bandwidth of the original link and realize the load sharing of traffic.
■当主用ETH-TRUNK中某条链路故障时，主用ETH-TRUNK会自动倒换到备用ETH-TRUNK，不会因为活动链路数减少引起流量拥塞。■When a link in the active ETH-TRUNK fails, the active ETH-TRUNK will automatically switch to the standby ETH-TRUNK, which will not cause traffic congestion due to the decrease in the number of active links.
■备用L3节点ETH-TRUNK UP＝N/2，当主用ETH-TRUNK故障自动倒换到备用ETH-TRUNK后，即使备用再有链路故障，只要故障链路数小于成员数N的一半，备用ETH-TRUNK会正常工作，可能会存在链路拥塞，但避免了业务阻断，能极大的避免重大故障发生。■Standby L3 node ETH-TRUNK UP=N/2, when the main ETH-TRUNK fails and automatically switches to the backup ETH-TRUNK, even if the backup has a link failure, as long as the number of failed links is less than half of the number of members N, the backup ETH -TRUNK will work normally, there may be link congestion, but it avoids service interruption and can greatly avoid major failures.
■部署Eth-Trunk后便于后续扩容，扩容时只需增加链路成员，而无需增发业务路由。■After Eth-Trunk is deployed, it is convenient for subsequent expansion. When expanding, only link members need to be added, and there is no need to issue additional service routes.
■Eth-Trunk对接时可部署BFD快速链路检查，同厂家对接可采用BFD for IP,异厂家聚合可采用BFD for Port。■BFD fast link check can be deployed when Eth-Trunk is interconnected, BFD for IP can be used for interconnection of the same manufacturer, and BFD for Port can be used for aggregation of different manufacturers.
3、2个原则，也即“LTE PTN本地网核心层关键单板分离原则和扩容原则3. Two principles, that is, "LTE PTN local network core layer key board separation principle and expansion principle
现网中两台L2/L3桥接设与主备L3设备之间均只部署一条10GE链路。若存在核心层物理同单板或者业务同路径，1处单板故障或者1处光缆故障就可能导致整个地市业务全阻，该类型情况在2015年全国也发生多起。本专利提出了LTE PTN本地网核心层关键单板分离原则和扩容原则，对于现网维护、优化和网络设计具有重要的指导作用。Only one 10GE link is deployed between the two L2/L3 bridge devices and the active and standby L3 devices on the live network. If there is a core layer with the same physical board or the same business path, a single board failure or a single optical cable failure may lead to a complete blockage of services in the entire city. This type of situation also occurred in many cases across the country in 2015. This patent proposes the principle of separation and expansion of key boards in the core layer of the LTE PTN local network, which plays an important role in guiding the maintenance, optimization and network design of the existing network.
3.1、LTE PTN本地网核心层关键单板分离原则3.1. The principle of separation of key boards in the core layer of the LTE PTN local network
本地网LTE PTN核心层物理同单板是指L3 PTN设备、L2/L3 PTN设备的上联端口、互联端口、下联端口中不存在于同一块单板上。如上图10中的链路1、2、3或者1、2、4存在同物理单板。The physical same board at the LTE PTN core layer of the local network means that the uplink ports, interconnection ports, and downlink ports of L3 PTN devices and L2/L3 PTN devices do not exist on the same board. Links 1, 2, and 3 or links 1, 2, and 4 in Figure 10 above exist on the same physical board.
核心层业务同路径是指L3VPN中涉及到的所有LSP 1:1保护的主备路径除了源宿节点的落地板位外，主备路由经过了同一个PTN板位、同一端PTN设备或同一波分路由。The same path for core layer services refers to the active and standby paths of all LSPs involved in L3VPN 1:1 protection, except for the floor positions of the source and sink nodes. sub-routing.
(1)L3 PTN设备上联省干单板、互联另外一台L3 PTN设备单板、下联L2/L3设备不能共单板，即上图中链路1、2、3、4要使用在不同的单板，防止1块单板故障引起2条链路阻断或者1块单板故障引起2对L2/L3设备单边运行。(1) The L3 PTN device's uplink and provincial trunk boards, interconnection with another L3 PTN device board, and downlink L2/L3 devices cannot share the same board, that is, links 1, 2, 3, and 4 in the above figure must be used It can prevent two links from being blocked due to the failure of one board or the unilateral operation of two pairs of L2/L3 devices caused by the failure of one board.
(2)L2/L3 PTN设备间承载ICB/ICCP心跳协议的主备物理链路不能共单板，链路不能有物理同路由，如上图中链路5、6，具体原则如下：(2) The active and standby physical links carrying the ICB/ICCP heartbeat protocol between L2/L3 PTN devices cannot share a single board, and the links cannot have the same physical route, such as links 5 and 6 in the above figure. The specific principles are as follows:
●L2/L3 PTN设备间互联端口不能共单板，即互联链路至少要分担在两块物理单板，防止1块单板故障引起2条链路阻断。● The interconnection ports between L2/L3 PTN devices cannot share a single board, that is, the interconnection link must be shared by at least two physical boards to prevent the failure of one single board from causing two links to be blocked.
●L2/L3 PTN设备间互联链路不应承载在一个波分系统。即L2/L3 PTN设备间互联的2条链路至少要承载在两个波分系统，且两个波分路径不能有同路由。● The interconnection link between L2/L3 PTN equipment should not be carried in a WDM system. That is, the two links interconnected between L2/L3 PTN devices must be carried by at least two WDM systems, and the two WDM paths cannot have the same route.
●L2/L3 PTN设备间互联物理链路不能承载在一根局间光缆中。即L2/L3 PTN设备间互联的2条链路至少要承载在两根光缆中，根据波分系统路由所走的物理路径，将2条链路至少要承载在两根光缆中。●The physical link between L2/L3 PTN devices cannot be carried by an inter-office optical cable. That is, the two links interconnected between L2/L3 PTN devices must be carried by at least two optical cables, and the two links must be carried by at least two optical cables according to the physical path taken by the WDM system routing.
(3)L2/L3 PTN设备上联L3设备单板、L2/L3PTN设备间承载L3VPN链路的单板不能共单板，防止1块单板故障引起LTE基站上流流量阻断。(3) The L2/L3 PTN equipment uplinks the L3 equipment board, and the board carrying the L3VPN link between the L2/L3PTN equipment cannot share a single board to prevent the upstream traffic of the LTE base station from being blocked due to the failure of one single board.
(4)华为L2/L3 PTN设备间承载DNI PW环网的主备物理链路不能共单板，链路不能有物理同路由，要求同承载ICB的链路要求。(4) The active and standby physical links of the DNI PW ring network between Huawei L2/L3 PTN equipment cannot share a single board, and the links cannot have the same physical route, and the requirements for the link carrying the ICB are the same.
(5)中兴L2/L3 PTN下联汇聚环的单板不能与L2/L3 PTN设备间承载该汇聚环基站PW双归的互联单板共板，防止1块单板故障引起一个汇聚环承载的LTE基站下行流量阻断。(5) The single board of the ZTE L2/L3 PTN downlink convergence ring cannot carry the dual-homing interconnection single board of the convergence ring base station PW with the L2/L3 PTN equipment, so as to prevent the failure of one single board from causing the LTE network carried by a convergence ring. The downlink traffic of the base station is blocked.
(6)业务路径同路由需分离，L3VPN中涉及到的所有LSP 1:1保护的主备路径，除源宿节点外不能存在业务同路径、PTN同单板、波分同路由问题，谨防设备间物理链路有多条链路而业务路径存在同路由隐患。(6) The service path and the route need to be separated. All LSP 1:1 protection active and standby paths involved in L3VPN, except the source and sink nodes, cannot have the same business path, PTN on the same board, and WDM on the same route. There are multiple links in the physical link between them, and there is a risk of the same route in the service path.
3.2、LTE PTN本地网核心层关键单板扩容原则3.2. Expansion principles of key boards in the core layer of the LTE PTN local network
从城域传送网312优化法的LTE PTN本地网核心层关键单板分离原则可以看出，核心层链路扩容时也必须要遵循一定的原则，随意的选择单板、端口扩容可能无法起到提高安全性的作用。为此，城域传送网312优化法也提出了LTE PTN本地网核心层扩容原则。From the principle of separation of key boards in the core layer of the LTE PTN local network based on the 312 optimization method of the metro transport network, it can be seen that certain principles must be followed when expanding the link capacity of the core layer. Random selection of boards and port expansion may not be effective. Enhance the role of security. For this reason, the metropolitan area transmission network 312 optimization method also proposes the principle of expanding the core layer of the LTE PTN local network.
(1)、安全性最优原则：在槽位满足的情况，选择空闲槽位新插单板，采用跨版链路聚合和分担，排除共单板的隐患。(1) The principle of optimal security: When the slots are satisfied, select a free slot to insert a new board, and use cross-version link aggregation and sharing to eliminate the hidden danger of shared boards.
(2)、在槽位不满足或者投资不满足情况，利旧现网单板和端口，优选L3设备上行链路使用单板和下行链路使用单板共板，按照现网保护方式，该方式不会影响现网业务。(2) When the slots are not satisfied or the investment is not satisfied, use the old existing network boards and ports, and preferably use single boards for the uplink of L3 equipment and shared boards for the downlink. According to the protection mode of the existing network, the This method will not affect the live network services.
(3)、在上述1、2无法满足条件下，仍需要扩容时选择上行链路和互联链路共单板或者下行链路和互联链路共单板，但此种情况必须满足原链路的上行链路和互联链路不共单板，下行链路和互联链路不共单板，否则一处单板故障将导致整个地市LTE业务阻断。(3) When the above conditions 1 and 2 cannot be satisfied, the uplink and interconnection link share a single board or the downlink and interconnection link share a single board, but in this case the original link must be satisfied. The uplink and interconnection link do not share a single board, and the downlink and interconnection link do not share a single board. Otherwise, a single board failure will block LTE services in the entire city.
(4)、城域传送网L3VPN内部扩容采用本专利创新点中提出的VPN Peer部署ECMP，城域传送网L3VPN和省干L3VPN对接链路扩容时采用创新点中提出多链路非对称聚合。(4) The internal expansion of L3VPN in the metropolitan area transport network adopts the VPN Peer deployment ECMP proposed in the innovation point of this patent, and the multi-link asymmetric aggregation proposed in the innovation point is adopted in the expansion of the connection link between the L3VPN in the metropolitan area transport network and the provincial backbone L3VPN.
4、技术方案验证4. Technical solution verification
一种城域传送网LTE PTN核心层312优化方法，经在内蒙古移动T地市分公司全网验证，方案满足预期要求，具体如下：A method for optimizing the LTE PTN core layer 312 of a metropolitan area transmission network. After the verification of the entire network of Inner Mongolia Mobile T City Branch, the solution meets the expected requirements, and the details are as follows:
4.1、网络倒换测试拓扑4.1. Network switching test topology
测试拓扑：对城域传送网LTE PTN核心层中原有相关网元和链路使用数字1到12进行编号，如图11所示，其中绿色路线表示新扩容链路。Test topology: number the original relevant network elements and links in the LTE PTN core layer of the metro transport network with numbers 1 to 12, as shown in Figure 11, where the green line represents the new expansion link.
按照前文分析，如下14种场景会造成业务阻断，即会引起城域传送网承载的地市eNodeB基站到EPC核心网的S1接口业务阻断。According to the previous analysis, the following 14 scenarios will cause service interruption, that is, the service interruption of the S1 interface between the urban eNodeB base station carried by the metro transport network and the EPC core network.
4.2、网络倒换测试方法4.2. Network switching test method
城域传送网LTE PTN核心层经过312优化方法优化后，采用关闭激光器或者现场拔线方式模拟此14种场景，每种场景的测试中，均在LTE核心网侧进行10000次1000字节的MME到基站的ICMP报文Ping测试，并在地市进行LTE手机的下载测试，下载文件均为省公司LTE测速服务器的500M Bits的大文件。After the LTE PTN core layer of the metropolitan area transmission network is optimized by the 312 optimization method, the 14 scenarios are simulated by turning off the laser or pulling out the cable on site. In the test of each scenario, 10,000 times of 1,000-byte MME are performed on the LTE core network side. Ping test of ICMP message to the base station, and download test of LTE mobile phone in prefectures and cities. The downloaded files are all large files of 500M Bits on the LTE speed test server of the provincial company.
经过测试，城域传送网LTE PTN核心层经过312优化方法优化后上述故障场景不再导致LTE业务中断，当某处或者两处故障发生后，城域传送网核心层会响应的保护倒换，LTE业务流量不中断，切换时延小于50毫秒，LTE业务无丢包，对比倒换前后LTE手机下载速率，无明显变化。对比保护倒换前后的LTE基站和EPC核心网间的时延、抖动、丢包率等重要网络指标，均无显著变化，整个保护倒换满足LTE承载的业务质量要求。After testing, the LTE PTN core layer of the metro transport network has been optimized by the 312 optimization method. The above fault scenarios will no longer cause LTE service interruption. The service flow is not interrupted, the switching delay is less than 50 milliseconds, there is no packet loss in the LTE service, and there is no significant change in the download rate of the LTE mobile phone before and after the switchover. Comparing important network indicators such as delay, jitter, and packet loss rate between the LTE base station and the EPC core network before and after protection switching, there is no significant change, and the entire protection switching meets the service quality requirements of LTE bearers.
当模拟的故障恢复后，网络可自动回切到原流量模型，整个过程能够平滑倒换，无丢包产生。When the simulated fault is recovered, the network can automatically switch back to the original traffic model, and the whole process can be switched smoothly without packet loss.
4.3网络倒换算法4.3 Network switching algorithm
本发明中网络倒换算法涉及的核心算法如下：The core algorithm involved in the network switching algorithm in the present invention is as follows:
当城域传送网LTE PTN核心层发生单点或者两点故障产生时，优化后的城域网核心层倒换算法：When a single-point or two-point fault occurs at the LTE PTN core layer of the metro transport network, the optimized metropolitan area network core layer switching algorithm:
●当某条链路或者单板故障时，首先发生部署的两点环网的保护倒换，主、备Tunnel不发生倒换。●When a link or a single board fails, the protection switching of the deployed two-point ring network occurs first, and the active and standby tunnels do not switch.
●当两处故障发生时，若两处故障发生在一对L3VPN Peer间，则发生主、备Tunnel的倒换；若两处故障发生在不同对L3VPN Peer间时，则每对L3VPN Peer各自独立发生两点环网的保护倒换，而无需发生主、备Tunnel的倒换。●When two faults occur, if the two faults occur between a pair of L3VPN Peers, the switchover of the active and standby tunnels will occur; if the two faults occur between different pairs of L3VPN Peers, each pair of L3VPN Peers will occur independently The protection switching of the two-point ring network does not require the switching of the active and standby tunnels.
●当发生节点故障或者四处链路故障时，工作源PE对工作宿PE设备的主备路径均故障，此时发生VPN FRR保护，工作源PE倒换至保护宿PE设备，而不引起业务阻断。●When a node failure or four link failures occur, both the active and standby paths of the working source PE to the working sink PE equipment fail, and VPN FRR protection occurs at this time, and the working source PE switches to the protection sink PE equipment without causing service interruption .
●城域L3设备对接省干L3设备的倒换，当主用ETH-TRUNK中某条链路故障时，主用ETH-TRUNK会自动倒换到备用ETH-TRUNK，不会因为活动链路数减少引起流量拥塞。●Switching between metropolitan L3 equipment and provincial trunk L3 equipment, when a link in the active ETH-TRUNK fails, the active ETH-TRUNK will automatically switch to the standby ETH-TRUNK, which will not cause traffic due to the decrease in the number of active links congestion.
●城域L3设备对接省干L3设备的倒换，当主用ETH-TRUNK中某条链路故障时，备用ETH-TRUNK有1条物理链路故障时，主用ETH-TRUNK会自动倒换到备用ETH-TRUNK，备用L3节点将流量从2个物理成员倒换至一个活动的物理成员链路，即只要故障链路数小于成员数N的一半，备用ETH-TRUNK会正常工作，可能会存在链路拥塞，但避免了业务阻断，能极大的避免重大故障发生。●Switching between metropolitan L3 equipment and provincial trunk L3 equipment, when a link in the active ETH-TRUNK fails and one physical link of the standby ETH-TRUNK fails, the active ETH-TRUNK will automatically switch to the standby ETH -TRUNK, the standby L3 node switches traffic from 2 physical members to an active physical member link, that is, as long as the number of failed links is less than half of the number N of members, the standby ETH-TRUNK will work normally, and there may be link congestion , but avoids service interruption and can greatly avoid major failures.
故障消失时的算法，如图12所示，包括：The algorithm when the fault disappears, as shown in Figure 12, includes:
●在城域传送网LTE PTN核心层设备采用MPLS OAM、MPLS-TP OAM检测LSP和环网的故障，同时采用802.3ae和BFD技术快速检测10GE端口的故障，若原LSP路径不可达时发生对应的环网倒换和LSP倒换，若原路由不可达时发生对应的VPN FRR倒换。当MPLS OAM、MPLS-TP OAM检测LSP和环网的故障和采用802.3ae和BFD技术快速检测的10GE端口故障恢复正常，判断该节点对应的路径和路由从不可达变为可达；●LTE PTN core layer equipment in the metro transport network uses MPLS OAM and MPLS-TP OAM to detect LSP and ring network faults, and uses 802.3ae and BFD technologies to quickly detect 10GE port faults. If the original LSP path is unreachable, a corresponding fault occurs Ring network switching and LSP switching, if the original route is unreachable, the corresponding VPN FRR switching occurs. When MPLS OAM, MPLS-TP OAM detects LSP and ring network faults and adopts 802.3ae and BFD technology to quickly detect 10GE port faults and recovers to normal, it is judged that the path and route corresponding to the node have changed from unreachable to reachable;
●此时原路径或者原路由可用,触发环网保护、LSP保护和VPN FRR保护切回,业务又回到原流量模型。●At this time, the original path or route is available, triggering ring network protection, LSP protection and VPN FRR protection switchback, and the service returns to the original traffic model.
第二方面，本发明实施例还提供了一种路径保护方法，应用与第一方面所述的TD-LTE城域回传网络中，包括：In the second aspect, the embodiment of the present invention also provides a path protection method, which is applied to the TD-LTE metro backhaul network described in the first aspect, including:
在所述口字型组网中的任意两个节点之间进行流量传输时，将待传输的流量分担至组内的若干条隧道链路中传输；When performing traffic transmission between any two nodes in the zigzag network, distribute the traffic to be transmitted to several tunnel links in the group for transmission;
在口字型组网中的直接连接主用L2/L3桥接设备节点以及备用L2/L3桥接设备节点的四点环网的工作路径发生故障时，通过所述四点环网的环网路径传输流量；When the working path of the four-point ring network directly connected to the active L2/L3 bridge device node and the standby L2/L3 bridge device node in the word-shaped network fails, the ring network path transmission through the four-point ring network flow;
在所述口字型组网中的相邻两个节点之间两点环网中，在环路的其中一个方向故障时，通过环路另一个方向传输流量。In the two-point ring network between two adjacent nodes in the word-of-mouth network, when one direction of the ring fails, traffic is transmitted through the other direction of the ring.
在具体实施时，所述将待传输的流量分担至组内的若干条隧道链路中传输，包括：During specific implementation, the described traffic to be transmitted is allocated to several tunnel links in the group for transmission, including:
将待传输的流量分担至组内的N条隧道链路中传输，其中N大于或等于该隧道链路组中包含的隧道链路数的一半。Allocate the traffic to be transmitted to N tunnel links in the group for transmission, where N is greater than or equal to half the number of tunnel links included in the tunnel link group.
在具体实施时，所述方法还包括：During specific implementation, the method also includes:
在用于分担流量的N条激活隧道链路发生故障时，所述隧道链路组中除所述N条激活隧道链路外的保护链路继续分担并传输所述激活隧道链路要传输的流量。When the N active tunnel links used to share traffic fail, the protection links in the tunnel link group except for the N active tunnel links continue to share and transmit the traffic to be transmitted by the active tunnel links. flow.
由于在前文中已经对于本发明实施例提供的TD-LTE城域回传网络的工作流程进行了详细的描述，在此不再赘述基于该网络的路径保护方法。Since the working process of the TD-LTE metro backhaul network provided by the embodiment of the present invention has been described in detail above, the path protection method based on the network will not be repeated here.
应该注意的是上述实施例对本发明进行说明而不是对本发明进行限制，并且本领域技术人员在不脱离所附权利要求的范围的情况下可设计出替换实施例。在权利要求中，不应将位于括号之间的任何参考符号构造成对权利要求的限制。单词“包含”不排除存在未列在权利要求中的元件或步骤。位于元件之前的单词“一”或“一个”不排除存在多个这样的元件。本发明可以借助于包括有若干不同元件的硬件以及借助于适当编程的计算机来实现。在列举了若干装置的单元权利要求中，这些装置中的若干个可以是通过同一个硬件项来具体体现。单词第一、第二、以及第三等的使用不表示任何顺序。可将这些单词解释为名称。It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means can be embodied by one and the same item of hardware. The use of the words first, second, and third, etc. does not indicate any order. These words can be interpreted as names.
| Application Number | Priority Date | Filing Date | Title |
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| CN201710046609.6ACN108337144A (en) | 2017-01-20 | 2017-01-20 | The metropolitan areas TD-LTE return network, path protecting method |
| Application Number | Priority Date | Filing Date | Title |
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| CN201710046609.6ACN108337144A (en) | 2017-01-20 | 2017-01-20 | The metropolitan areas TD-LTE return network, path protecting method |
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| CN108337144Atrue CN108337144A (en) | 2018-07-27 |
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| CN201710046609.6APendingCN108337144A (en) | 2017-01-20 | 2017-01-20 | The metropolitan areas TD-LTE return network, path protecting method |
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| RJ01 | Rejection of invention patent application after publication | Application publication date:20180727 |