SSO/NSF with StackWise virtual

[Piyush Dixit1]

Hello,

Can we configure SSO/NSF betweent two 9500 paired using StackWise virtual and each having a single RP?

[Enes Simnica]

hello man. Yes u can configure SSO/NSF between two Catalyst 9500 switches in a StackWise Virtual (SWV) pair, even with a single RP per chassis. but u need to know some stuff first: SSO works for L2 protocols (STP, LACP) and some L3 features (e.g., OSPF NSF, BGP Graceful Restart). Also there are some requirements like : Identical IOS-XE versions on both switches, proper setup active/stanby roles,,,. and fo so NSFaware routing protocols. and u have some limitations like: Full L3 stateful failover requires dual RPs. With single RPs, expect brief control-plane downtime during switchover and more. 

However, I have had clients who preferred using only one RP link, and they experienced no issues whatsoever.... (thats real world man)

also man just so u know, I have extensive experience with the 9500, 9606R, and many other high performance devices. Feel free to reach out if u need in depth assistance with configuration.

hope it helps G

-Enes

[Enes Simnica]

also check these links G: 

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9500/software/release/17-15/configuration_guide/ha/b_1715_ha_9500_cg/configuring_cisco_stackwise_virtual.html 

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9500/software/release/17-13/configuration_guide/ha/b_1713_ha_9500_cg.html

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9500/software/release/17-9/configuration_guide/ha/b_179_ha_9500_cg/configuring_cisco_stackwise_virtual.html 

and this reddit link: https://www.reddit.com/r/networking/comments/1177ehv/cisco_9500_stackwise_and_bgp/ 

[MHM Cisco World]

I will reply later for this issue I know why you are confuse here

MHM

[Joseph W. Doherty]

---

@Piyush Dixit1 wrote:

Hello,

Can we configure SSO/NSF betweent two 9500 paired using StackWise virtual and each having a single RP?

---

Between them, no, because the pair operations as one logical device.  I.e. you just configure SSO/NSF on the virtual switch.

Single RP, each device, should be fine.

Basically, a StackWise pair logically operates much as a single chassis with redundant sups.  One's active, and one's standby.  With SSO standby is hot for L2, and with NSF, standby is hot for L3.

One problem with StackWise devices only having a single RP, if you lose the RP, you lose all that chassis's connections.  But, if you've have redundant connections to both pair members, you shouldn't lose any connectivity, but you will lose performance capacity.

If the standby StackWise member fails, migration to moving to active member probably under 50ms, i.e. like losing alternate line cards on the same chassis.

If the active StackWise member fails, compared to a single chassis with dual sups, transition time to standby becoming active, a bit more impactful, as again, all the prior active chassis ports lost, and (likely) just a bit slower to detect lost of active member.  Overall, probably comparable to single chassis with dual RPs.

Also again, if either StackWise Virtual member single RP fails, you've lost half your forwarding capacity.