Track and SLA Configuration Guide

introduction introduction track track to further improve network reliability, redundancy protection methods are commonly used in practice, where two devices backup each other and can also share the workload when one of the switches experiences a link failure, the other device can take over to continue forwarding user traffic this results in a situation where a device accesses both primary and backup devices this also creates issues of link reliability and load balancing between devices when part or all of the network side links fail, the bandwidth of these links’ decreases, and the access side may not immediately detect the occurrence of this failure, leading to network congestion or loss of traffic therefore, by configuring track monitoring groups, routes can be withdrawn promptly after a link failure to prevent traffic from being forwarded through the failed link sla sla link quality metrics serve as criteria for judging whether the links of intelligent route selection meet quality requirements when health checks and link quality metrics are referenced in global route selection policies or multi exit policy routing, the switch continuously checks whether the quality of interface links (delay, jitter, and packet loss rate) meets the quality requirements specified by the link quality metrics links that do not meet the requirements do not participate in intelligent route selection until the link quality meets the requirements again explanation of principles explanation of principles the network administrator configures static routes on the router, instructing the switch how to forward packets to the destination network additionally, the administrator configures route monitoring groups after configuring the route monitoring group, the switch actively sends icmp request packets to the specified ip address based on network performance and packet loss rate information, it determines whether the ip address is reachable when the target address is unreachable, the switch proactively withdraws the statically configured route, enabling fault tolerance in the network and ensuring high availability and stability track and sla configuration track and sla configuration configure sla configure sla configure sla policies to detect information such as network performance, reliability, and packet loss rate detect if the ip address is reachable by sending icmp request messages to the specified ip address this helps network administrators determine the optimal data transmission path table 1 configure sla instance table 1 configure sla instance purpose command description enter global configuration view configure terminal create an sla instance sla sla id icmp echo { a b c d | a b } id sla instance id,the value range is 1 4294967295 ip address specify the destination ip address (optional) configure the source port for sending probes set src port { ethernet interface name \[ subinterface number ]| link aggregation lag id \[ subinterface number ]| vlan vlan id } (optional) configure the icmp packet transmission interval set interval milliseconds milliseconds ：the range is \[200,3000] the default value is 200 (optional)configure the number of icmp probe packets set count count count the range is \[1,100] the default value is 5 (optional) configure the interval between two sla probes set frequency interval interval the range is \[1,3600] the default value is 10 (optional) configure the sla timeout duration set timeout seconds seconds the range is \[1,3600] the default value is 1 configure track configure track create track monitoring instance and bind it with a static route and sla instance when the destination ip address probed by sla is unreachable, use the track to notify the static route to delete, ensuring that packets are no longer forwarded through that route when the probing result of sla is restored, the static route is automatically restored table 2 create track instance and bind sla instance table 2 create track instance and bind sla instance purpose command description enter global configuration view configure terminal create a track instance and bind sla instance track track id sla sla id track id track instance id, the value range is 1 4294967295 sla id sla instance id, the value range is 1 4294967295 create static route and bind track instance ip route a b c d/m a b c d track track id display and maintenance display and maintenance table 3 sla and track display and maintenance table 3 sla and track display and maintenance purpose command description display sla info show sla summary display track info show track summary typical configuration example typical configuration example networking requirements in the network topology, switches use static routes for packet forwarding, and on switch1 and switch4, equal cost multi path (ecmp) is configured, with the next hops being switch2 and switch3 respectively when there is a link failure on either switch2 or switch3, switch1 and switch4 can promptly detect the link failure using track and sla functionalities and quickly converge the routes configure roadmap (1) connect the links according to the topology diagram and verify that all switch ports are up (2) configure ip for interfaces (3) configure sla (4) configure track (5) configure static routes procedure switch 1 configure ip for interfaces sonic(config)# interface ethernet 0/20 sonic(config if 0/20)# ip address 172 16 10 1/24 sonic(config if 0/20)# exit sonic(config)# interface ethernet 0/21 sonic(config if 0/21)# ip address 10 0 2 1/24 sonic(config if 0/21)# exit sonic(config)# interface ethernet 0/22 sonic(config if 0/22)# ip address 10 0 3 1/24 sonic(config if 0/22)# exit configure sla sonic(config)# sla 1 icmp echo 10 0 2 2 sonic(config sla icmp echo)# set src port ethernet 0/21 sonic(config sla icmp echo)# exit sonic(config)# sla 2 icmp echo 10 0 3 2 sonic(config sla icmp echo)# set src port ethernet 0/22 sonic(config sla icmp echo)# exit configure track sonic(config)# track 1 sla 1 sonic(config)# track 2 sla 2 configure routes sonic(config)# ip route 172 16 20 1/24 10 0 2 2 track 1 sonic(config)# ip route 172 16 20 1/24 10 0 3 2 track 2 switch2 configure ip for interfaces sonic(config)# interface ethernet 0/0 sonic(config if 0/0)# ip address 10 0 2 2/24 sonic(config if 0/0)# exit sonic(config)# interface ethernet 0/4 sonic(config if 0/4)# ip address 10 0 12 2/24 sonic(config if 0/4)# exit configure routes sonic(config)# ip route 172 16 20 1/24 10 0 12 1 sonic(config)# ip route 172 16 10 1/24 10 0 2 1 switch3 configure ip for interfaces sonic(config)# interface ethernet 0/0 sonic(config if 0/0)# ip address 10 0 3 2/24 sonic(config if 0/0)# exit sonic(config)# interface ethernet 0/4 sonic(config if 0/4)# ip address 10 0 13 2/24 sonic(config if 0/4)# exit configure routes sonic(config)# ip route 172 16 20 1/24 10 0 13 1 sonic(config)# ip route 172 16 10 1/24 10 0 3 1 switch4 configure ip for interfaces sonic(config)# interface ethernet 0/20 sonic(config if 0/20)# ip address 172 16 20 1/24 sonic(config if 0/20)# exit sonic(config)# interface ethernet 0/21 sonic(config if 0/21)# ip address 10 0 12 1/24 sonic(config if 0/21)# exit sonic(config)# interface ethernet 0/22 sonic(config if 0/22)# ip address 10 0 13 1/24 sonic(config if 0/22)# exit configure sla sonic(config)# sla 1 icmp echo 10 0 12 2 sonic(config sla icmp echo)# set src port ethernet 0/21 sonic(config sla icmp echo)# exit sonic(config)# sla 2 icmp echo 10 0 13 2 sonic(config sla icmp echo)# set src port ethernet 0/22 sonic(config sla icmp echo)# exit configure track sonic(config)# track 1 sla 1 sonic(config)# track 2 sla 2 configure routes sonic(config)# ip route 172 16 10 1/24 10 0 12 2 track 1 sonic(config)# ip route 172 16 10 1/24 10 0 13 2 track 2 verify the configuration switch1 display track and sla configuration sonic# show track summary track id bind sla id state \ 1 1 success 2 2 success sonic# show sla summary \===================================icmp echo==================================== sla id type dst ip min time avg time max time packt loss \ 1 icmp echo 10 0 2 2 0 223 0 321 0 398 0 0% 2 icmp echo 10 0 3 2 0 199 0 243 0 295 0 0% switch 1 has ecmp routes to switch 4 sonic# show ip route codes k kernel route, c connected, s static, r rip, o ospf, i is is, b bgp, e eigrp, n nhrp, t table, v vnc, v vnc direct, a babel, f pbr, f openfabric, \> selected route, fib route, q queued, r rejected, b backup t trapped, o offload failure s> 172 16 20 0/24 \[1/0] via 10 0 2 2, ethernet21, weight 1, 00 00 14 via 10 0 3 2, ethernet22, weight 1, 00 00 14 a link failure occurs on the path from switch 1 to switch 2 to switch 4, sla1 packet loss rate reaches 100%, and switch 1 withdraws the route from switch 2 to switch 4 sonic# show sla summary \===================================icmp echo==================================== sla id type dst ip min time avg time max time packt loss \ 1 icmp echo 10 0 2 2 0 0 0 100% 2 icmp echo 10 0 3 2 0 729 1 273 1 673 0% sonic# show track summary track id bind sla id state \ 1 1 failure 2 2 success sonic(config)# do show ip route codes k kernel route, c connected, s static, r rip, o ospf, i is is, b bgp, e eigrp, n nhrp, t table, v vnc, v vnc direct, a babel, f pbr, f openfabric, \> selected route, fib route, q queued, r rejected, b backup t trapped, o offload failure s> 172 16 20 0/24 \[1/0] via 10 0 2 2, ethernet21, weight 1, 00 00 14(unreachable) via 10 0 3 2, ethernet22, weight 1, 00 00 14