GR配置举例
1.组网需求
· Switch A、Switch B和Switch C既属于同一自治系统，也属于同一OSPF域，通过OSPF协议实现网络互连，并提供GR机制。
· Switch A作为非IETF标准GR Restarter，Switch B和Switch C作为GR Helper并且通过GR机制与Switch A保持带外同步。
2.配置
1）配置OSPF基本功能
SW A [SwitchA] router id 1.1.1.1 [SwitchA] ospf 100 [SwitchA-ospf-100] area 0 [SwitchA-ospf-100-area-0.0.0.0] network 192.1.1.0 0.0.0.255 SW B [SwitchB] router id 2.2.2.2 [SwitchB] ospf 100 [SwitchB-ospf-100] area 0 [SwitchB-ospf-100-area-0.0.0.0] network 192.1.1.0 0.0.0.255 SW C [SwitchC] router id 3.3.3.3 [SwitchC] ospf 100 [SwitchC-ospf-100] area 0 [SwitchC-ospf-100-area-0.0.0.0] network 192.1.1.0 0.0.0.255
2）配置OSPF GR
[SwitchA] ospf 100 [SwitchA-ospf-100] enable link-local-signaling [SwitchA-ospf-100] enable out-of-band-resynchronization [SwitchA-ospf-100] graceful-restart # 配置Switch A作为非IETF标准GR Restarter，即使能OSPF进程100的本地链路信令能力、OSPF带外同步能力和非IETF标准GR能力。 [SwitchB] ospf 100 [SwitchB-ospf-100] enable link-local-signaling [SwitchB-ospf-100] enable out-of-band-resynchronization # 配置Switch B作为GR Helper，即使能OSPF进程100的本地链路信令能力和OSPF带外同步能力。 [SwitchC] ospf 100 [SwitchC-ospf-100] enable link-local-signaling [SwitchC-ospf-100] enable out-of-band-resynchronization # 配置Switch C作为GR Helper，即使能OSPF进程100的本地链路信令能力和OSPF带外同步能力。
3.验证配置
# 打开Switch A的OSPF平滑启动事件调试信息开关。在Switch A上以GR方式重启OSPF进程。 <SwitchA> debugging ospf event graceful-restart <SwitchA> terminal monitor <SwitchA> terminal logging level 7 <SwitchA> reset ospf 100 process graceful-restart Reset OSPF process? [Y/N]:y %Oct 21 15:29:28:727 2019 SwitchA OSPF/5/OSPF_NBR_CHG: OSPF 100 Neighbor 192.1.1.2(Vlan-interface100) from Full to Down. %Oct 21 15:29:28:729 2019 SwitchA OSPF/5/OSPF_NBR_CHG: OSPF 100 Neighbor 192.1.1.3(Vlan-interface100) from Full to Down. *Oct 21 15:29:28:735 2019 SwitchA OSPF/7/DEBUG: OSPF 100 nonstandard GR Started for OSPF Router *Oct 21 15:29:28:735 2019 SwitchA OSPF/7/DEBUG: OSPF 100 created GR wait timer,timeout interval is 40(s). *Oct 21 15:29:28:735 2019 SwitchA OSPF/7/DEBUG: OSPF 100 created GR Interval timer,timeout interval is 120(s). *Oct 21 15:29:28:758 2019 SwitchA OSPF/7/DEBUG: OSPF 100 created OOB Progress timer for neighbor 192.1.1.3. *Oct 21 15:29:28:766 2019 SwitchA OSPF/7/DEBUG: OSPF 100 created OOB Progress timer for neighbor 192.1.1.2. %Oct 21 15:29:29:902 2019 SwitchA OSPF/5/OSPF_NBR_CHG: OSPF 100 Neighbor 192.1.1.2(Vlan-interface100) from Loading to Full. *Oct 21 15:29:29:902 2019 SwitchA OSPF/7/DEBUG: OSPF 100 deleted OOB Progress timer for neighbor 192.1.1.2. %Oct 21 15:29:30:897 2019 SwitchA OSPF/5/OSPF_NBR_CHG: OSPF 100 Neighbor 192.1.1.3(Vlan-interface100) from Loading to Full. *Oct 21 15:29:30:897 2019 SwitchA OSPF/7/DEBUG: OSPF 100 deleted OOB Progress timer for neighbor 192.1.1.3. *Oct 21 15:29:30:911 2019 SwitchA OSPF/7/DEBUG: OSPF GR: Process 100 Exit Restart,Reason : DR or BDR change,for neighbor : 192.1.1.3. *Oct 21 15:29:30:911 2019 SwitchA OSPF/7/DEBUG: OSPF 100 deleted GR Interval timer. *Oct 21 15:29:30:912 2019 SwitchA OSPF/7/DEBUG: OSPF 100 deleted GR wait timer. %Oct 21 15:29:30:920 2019 SwitchA OSPF/5/OSPF_NBR_CHG: OSPF 100 Neighbor 192.1.1.2(Vlan-interface100) from Full to Down. %Oct 21 15:29:30:921 2019 SwitchA OSPF/5/OSPF_NBR_CHG: OSPF 100 Neighbor 192.1.1.3(Vlan-interface100) from Full to Down. %Oct 21 15:29:33:815 2019 SwitchA OSPF/5/OSPF_NBR_CHG: OSPF 100 Neighbor 192.1.1.3(Vlan-interface100) from Loading to Full. %Oct 21 15:29:35:578 2019 SwitchA OSPF/5/OSPF_NBR_CHG: OSPF 100 Neighbor 192.1.1.2(Vlan-interface100) from Loading to Full.
从上面的信息可以看出Switch A完成了GR。
NSR配置举例
1.Switch S、Switch A、Switch B属于同一OSPF区域，通过OSPF协议实现网络互连。要求对Switch S进行主备倒换时，Switch A和Switch B到Switch S的邻居没有中断，Switch A到Switch B的流量没有中断。
2.配置
1）配置各路由器接口的IP地址和OSPF协议
配置各交换机之间采用OSPF协议进行互连，确保Switch S、Switch A和Switch B之间能够在网络层互通，并且各交换机之间能够借助OSPF协议实现动态路由更新。
2）配置OSPF NSR
[SwitchS] ospf 100 [SwitchS-ospf-100] non-stop-routing # 使能Switch S的OSPF NSR功能。
3.配置验证
# Switch S进行主备倒换。 [SwitchS] placement reoptimize Predicted changes to the placement Program Current location New location --------------------------------------------------------------------- rib 0/0 0/0 staticroute 0/0 0/0 ospf 0/0 1/0 Continue? [y/n]:y Re-optimization of the placement start. You will be notified on completion. Re-optimization of the placement complete. Use 'display placement' to view the new placement.
# 查看Switch A/B上OSPF协议的邻居和路由。 <SwitchA> display ospf peer OSPF Process 1 with Router ID 2.2.2.1 Neighbor Brief Information Area: 0.0.0.0 Router ID Address Pri Dead-Time State Interface 3.3.3.1 12.12.12.2 1 37 Full/BDR Vlan100 <SwitchA> display ospf routing OSPF Process 1 with Router ID 2.2.2.1 Routing Table Topology base (MTID 0) Routing for network Destination Cost Type NextHop AdvRouter Area 44.44.44.44/32 2 Stub 12.12.12.2 4.4.4.1 0.0.0.0 14.14.14.0/24 2 Transit 12.12.12.2 4.4.4.1 0.0.0.0 22.22.22.22/32 0 Stub 22.22.22.22 2.2.2.1 0.0.0.0 12.12.12.0/24 1 Transit 12.12.12.1 2.2.2.1 0.0.0.0 Total nets: 4 Intra area: 4 Inter area: 0 ASE: 0 NSSA: 0
通过上面信息可以看出在Switch S发生主备倒换的时候，Switch A和Switch B的邻居和路由信息保持不变，从Switch A到Switch B的流量转发没有受到主备倒换的影响。