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Ping drop when shutting down primary chassis of VSS


I had setup a VSS using a pair of WS-C4507R+E recently. Both chassis has a single sup card (WS-X45-SUP7L-E).

For testing purpose, i had connected a laptop and a router to the secondary chassis. The router is forming a EIGRP adjacency with the secondary chassis usign a L3 point to point link. The laptop is connected to VLAN22 which has a SVI on the VSS. The laptop is used to ping an ip address on the router.

When I power off the primary chassis, there is 1 packet drop on the continous ping and I got the following messages in my log.

000027: *Jul 12 08:58:47.218 SGT: %VSLP-3-VSLP_LMP_FAIL_REASON: STANDBY:Te2/3/2: Link down

000028: *Jul 12 08:58:47.231 SGT: %VSLP-3-VSLP_LMP_FAIL_REASON: STANDBY:Te2/3/1: Link down

000029: *Jul 12 08:58:47.231 SGT: %VSLP-2-VSL_DOWN: STANDBY:  All VSL links went down while switch is in Standby role

000030: *Jul 12 08:58:47.231 SGT: %EC-5-UNBUNDLE: STANDBY:Interface TenGigabitEthernet2/3/1 left the port-channel Port-channel2

000031: *Jul 12 08:58:47.233 SGT: %EC-5-UNBUNDLE: STANDBY:Interface TenGigabitEthernet2/3/2 left the port-channel Port-channel2

000032: *Jul 12 08:58:47.247 SGT: %C4K_REDUNDANCY-6-INIT: Initializing as ACTIVE supervisor

000033: *Jul 12 08:58:47.281 SGT: %C4K_REDUNDANCY-3-COMMUNICATION: Communication with the peer Supervisor has been lost

000034: *Jul 12 08:58:47.318 SGT: %C4K_REDUNDANCY-3-SIMPLEX_MODE: The peer Supervisor has been lost

000035: *Jul 12 08:58:48.209 SGT: %EC-5-UNBUNDLE: Interface TenGigabitEthernet1/3/1 left the port-channel Port-channel1

000036: *Jul 12 08:58:48.216 SGT: %EC-5-UNBUNDLE: Interface TenGigabitEthernet1/3/2 left the port-channel Port-channel1

000037: *Jul 12 08:58:48.467 SGT: %PIM-5-DRCHG: DR change from neighbor to on interface Loopback1

000038: *Jul 12 08:58:48.467 SGT: %PIM-5-DRCHG: DR change from neighbor to on interface GigabitEthernet2/1/21

000039: *Jul 12 08:58:48.467 SGT: %PIM-5-DRCHG: DR change from neighbor to on interface Vlan22

000040: *Jul 12 08:58:49.484 SGT: %PIM-5-NBRCHG: neighbor UP on interface GigabitEthernet2/1/21

000041: *Jul 12 08:58:54.662 SGT: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor (GigabitEthernet2/1/21) is up: new adjacency

Is it normal for the EIGRP to lose adjacency and experience ping drop? Shouldn't the secondary chassis continue functioning?

Q. What high-availability mechanisms are available with a VSS?

A. A VSS uses interchassis NSF/SSO as the primary mechanism for high  availability between the two chassis. One virtual switch member chassis  will act as the active virtual switch member, while the other member  will be in hot standby state for the control plane. Note that the data  planes of both chassis are active and hence forward traffic at full  combined capacity of 1440 Gbps. When one of the virtual switch members  fails, there is no reconvergence of protocols in the network. The access  layer or core layer switches continues to forward traffic because they  only detect a link failure in an EtherChannel bundle and hence do not  need to reconverge any protocols. No disruption occurs to the traffic  flowing through the VSS. The VSS mechanism during switch failure is far  superior when comparison with the traditional model where one switch  failure results indeterminist convergence of multiple control protocols  like STP, HSRP and routing protocol.




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