topic Re: Extreme Fabric vist Layer 3 redundancy in ExtremeSwitching (VSP/Fabric Engine)

Extreme Fabric vist Layer 3 redundancy

Ahmed_101 — Tue, 07 Oct 2025 18:17:09 GMT

Hi all,
I have a deployment where i have 2 VSP core switches running in vist cluster.
The edge switches is connected using two links, one is connected to the first switch and the other link is connected to the second switch which is smlt config.
These switches is connected to the isp router using one vlan and ip so all the traffic is routed to this ip.
Core A have vlans and ip addresses of these vlans, core b have the same vlans but with out ip addresses. so i have this problem where the layer 3 is on just one of these voss switches so there is no real layer 3 redundancy for the clients.
My goal is to configure vlans layer 3 interfaces in both switches to provide gateway redundancy for the clients so when one switch goes down the other one takes the routing task.
as i researches i found out that i can configure rsmlt or anycast gate way to achieve this.
which one is better and easier to configure ?
Thanks in advance.

Re: Extreme Fabric vist Layer 3 redundancy

gfriedl — Wed, 08 Oct 2025 12:34:30 GMT

you did not state, what is the routing protocol in between your core and the ISP router. usually one would use a static route, pointing to a virtual IP address on both VSPs. VRRP or IP Anycast GW are options and both are configured similar. Just remember, that for IP ACGW to work you would need at least release 9.1.

if you would use dynamic routing, than the need for Virtual IP goes away and protocol would take care of failover.

Re: Extreme Fabric vist Layer 3 redundancy

EF — Wed, 08 Oct 2025 12:34:38 GMT

vrrp

Re: Extreme Fabric vist Layer 3 redundancy

Ahmed_101 — Wed, 08 Oct 2025 13:35:58 GMT

We do not use any routing protocol we use one static route to point all the traffic to that ip address.
so if i configured rsmlt or vrrp in both vsp will this still work ?

Re: Extreme Fabric vist Layer 3 redundancy

Ahmed_101 — Wed, 08 Oct 2025 13:36:06 GMT

Thanks.

Re: Extreme Fabric vist Layer 3 redundancy

WillyHe — Thu, 09 Oct 2025 08:24:58 GMT

VRRP and RSMLT, both can do the job.

For VRRP you need tree IP addresses.
On the vIST cluster, one virtual (VRRP) address.
Two VLAN IP interface addresses (one for each cluster member).
For RSMLT you need two IP addresses, the VLAN IP interface addresses (one for each cluster member), one of these addresses must be the next hop routing address configured on the firewall (and other VLAN client systems).
You must configure the RSMLT HOLDUP-TIMER to 9999, then the partners MAC address is saved in the configuration and e.g. when there is a power cut and the next-hop router/default-GW cluster member doesn't come up again the other cluster member loads the next-hop router/default-GW from the configuration.

SMLT_CLUSTER_MEMBER-1:1(config-if)#ip rsmlt holdup-timer ?
<0-9999> Holdup timer value {0-3600} and infinty = 9999

PRO: You can configure/enable RSMLT on the cluster member were the VLAN IP's are configured without interrupting traffic.

CON: you can configure RSMLT as next-hop router/default-GW on ONE SMLT cluster.

Hope it helps in your decision.

regards
WillyHe

Re: Extreme Fabric vist Layer 3 redundancy

Ahmed_101 — Thu, 09 Oct 2025 12:25:41 GMT

Hi,
Thank you for your reply, i will try vrrp bcs there is one link from the isp router connected to one of the vist cluster so the customer will physically replace the cable to the second switch in case of the first switch fails.
I will try it and write un update here.
Thank you.

Re: Extreme Fabric vist Layer 3 redundancy

Ahmed_101 — Mon, 20 Oct 2025 15:45:02 GMT

i tried vrrp and it worked fine.
Thanks.

Re: Extreme Fabric vist Layer 3 redundancy

CordScott — Thu, 23 Oct 2025 12:15:40 GMT

As others have said VRRP or RSMT. I prefer VRRP.