Migrating cisco having vrrp/hsrp to extreme fabric SPBM

[Dhiraj]

I am migrating traditional cisco-based setup having HSRP installed using 2 Layer 3 cat4500 core switches & there are other cisco switches in distribution & access level.

I need to design the new network using end to end extreme fabric solution using 7520 switches in core & 5520 switches in distribution & access.

My question here is for L3 gateway redundancy which will be the best option to use. VRRP or IP Shortcuts.

[WillyHe · Accepted solution]

Depending on the new FabricEngine L3 CORE size, 2 switches or +2 switches you have two options.

1. R-SMLT: R-SMLT can only be configured on ONE pair of switches in an SPBM-SMLT.
   When you plan to add later more L3 switches in the CORE, you can better start with the second option.
2. VRRP: You must use VRRP if tree or more switches as L3 CORE ().

Migration scenarios:
Basic setup is ready (FABRIC setup is OK, VLAN/I-SID setup is OK, one of the SMLT cluster members has a non DefaultGW address configured (this can be alternated if desired)).

When the DefaultGW must stay the same.

1. R-SMLT: this is a big bang scenario, you must disable or delete HSRP on the first VLAN --> create the DefaultGW address "other" SMLT cluster member --> test DefaultGW and Host reach-ability, repeat this for all VLAN's.
2. VRRP: If there is a "smooth" conversion possible, then convert HSRP to VRRP on the Cisco's.
   If no smooth HSRP to VRRP conversion, then create all VLAN interface IP addresses on the new L3 CORE's, create also the VRRP addresses but leave these disabled.
   When done, disable or delete HSRP on the first VLAN --> enable VRRP on all new L3 CORE switches in that VLAN, repeat this for all VLAN's.

When the DefaultGW can change.
In this case you can, for both options (R-SMLT/VRRP), make the IP setup on the new L3 CORE's in parallel, migrate the client devices (via DHCP or static IP configuration) to use the new DefaultGW.

regards
WillyHe

[jerrygen · Accepted solution]

Hi Dhiraj,

When migrating to an Extreme Fabric using SPBM, the best approach for L3 gateway redundancy is to leverage IP Shortcuts with I-SID-based virtual gateways instead of traditional VRRP.

With SPBM, you don't need VRRP or HSRP—IP Shortcuts handle L3 routing across the fabric seamlessly. You can configure anycast gateways on both 7520 core switches, allowing them to share the same virtual IP/MAC, ensuring efficient redundancy and failover without protocol overhead.

It’s simpler, faster, and built for fabric-based designs. Let me know if you need example configs.

Regards

[Dhiraj]

Dear Jerrygen,

Thank you for the update. Can you please share the sample configurations for this scenario. How to use IP-Shortcuts or anycast gateway for L3 redundancy.

[WillyHe · Accepted solution]

Depending on the new FabricEngine L3 CORE size, 2 switches or +2 switches you have two options.

1. R-SMLT: R-SMLT can only be configured on ONE pair of switches in an SPBM-SMLT.
   When you plan to add later more L3 switches in the CORE, you can better start with the second option.
2. VRRP: You must use VRRP if tree or more switches as L3 CORE ().

Migration scenarios:
Basic setup is ready (FABRIC setup is OK, VLAN/I-SID setup is OK, one of the SMLT cluster members has a non DefaultGW address configured (this can be alternated if desired)).

When the DefaultGW must stay the same.

1. R-SMLT: this is a big bang scenario, you must disable or delete HSRP on the first VLAN --> create the DefaultGW address "other" SMLT cluster member --> test DefaultGW and Host reach-ability, repeat this for all VLAN's.
2. VRRP: If there is a "smooth" conversion possible, then convert HSRP to VRRP on the Cisco's.
   If no smooth HSRP to VRRP conversion, then create all VLAN interface IP addresses on the new L3 CORE's, create also the VRRP addresses but leave these disabled.
   When done, disable or delete HSRP on the first VLAN --> enable VRRP on all new L3 CORE switches in that VLAN, repeat this for all VLAN's.

When the DefaultGW can change.
In this case you can, for both options (R-SMLT/VRRP), make the IP setup on the new L3 CORE's in parallel, migrate the client devices (via DHCP or static IP configuration) to use the new DefaultGW.

regards
WillyHe

[ExtremeNorth]

Since all our routers run VOSS (VSP/Fabric Engine) we use RSMLT for gateway redundancy for all client vlans.  This requires setting up a virtual-ist between the gateway routers across the fabric.  Very simple to setup, but here is a link on the Extreme support portal:  https://extreme-networks.my.site.com/ExtrArticleDetail?an=000080204&q=voss%20rsmlt