Different using hsrp on vlan and physical port on Cisco 3750 switch

[asldavid]

Hi,

What the different between using hsrp on vlan interface and on physical port (routed port) on Cisco 3750 Switch? Wha the benefits?

Please advise.

Regards,

David

[Harish Balakrishnan]

Hello David,

couple of points from my end..

routed port gives you a faster convergence in terms of routing but this not really flexible when we are thinking about high availability.

When we go with SVI, this gives you enough  flexibility for extension/expansion but the covergence delay is more when

using with routing

wait for more experts to comment

regards

Harish.

[asldavid]

Hi Harish,

Thank for the prompt reply./

A vlan can contain number of physical ports.

Assuming  all the ports in the vlan are connecting to uplink, if we configure hsrp on that interface vlan, how does hsrp know when to failover ? when all the ports on the same vlan went down ? (assuming no track command is use)

Regards,

David

[Rolf Fischer]

David,

HSRP is used in the first instance for gateway-redundacy, e.g. in client VLANs.

If you use a routed port, you have to connect a switch to that port to connect the clients.

A c3750 doesn't support routed subinterfaces, so if you need more then 1 VLAN (which is normally the case), you have to use another Uplink for that (instead of simply use a trunk). Even the link to your HSRP standby router can't be the classic interswitch-link between them. Connecitvity ist formed across an access-switch - which is normally not desirable.

In addition, if the client-VLAN ist needed on another switch, you can't use an uplink of your c3570. This is not scalable and doesn't meet common Campus-LAN Design requirements.

HTH

Rolf