Redundant Gateway on Catalyst 3560's

[vbahuse]

I've got two 3560's setup with a trunk between them and all hosts on the network have two NICs installed (one NIC connected to each 3560). Each host participates on two VLANs for redundancy reasons.

On each client the two NICs have static IP addresses on separate VLANs and each have a default gateway which points to the corresponding VLAN interface on the 3560 associated with thet VLAN. Both 3560's are aware of both VLANs, among others, and use static routes for required inter-VLAN routing.

Now, there is a third VLAN that both 3560's are aware of for which trunk connected layer-2 switches, 2960's, have connected clients that don't have redundant connections to the network. These clients currently have a default gateway of a VLAN interface on one of the 3560's for routing.

This all works fine except I have defeated the purpose of the redundant 3560's because if the one that has the VLAN interface configured for the thrid VLAN dies I loose the routing between the third VLAN and either of the two redundant VLANs.

Finally the question! How do I configure the 3560's to both have the same VLAN interface IP address in a redundant fashion? That is, one will always do the routing unless it fails and then the other 3560 will become "active" and take over until the first one has recovered.

I hope that I have clearly explained this!

 

[burtsbees]

HSRP.

Burt

 

[vbahuse]

When using HSRP does the cluster command switch have to do all inter-VLAN routing or can my two 3560's share the load under normal conditions (i.e. I have 10 VLANs which each ave default gateways that reside on one of the 3560's and currently they share the load with 5 each)?

Cheers

 

[brianinms]

If you have 10 vlans than merely set the preference such that 5 route on one switch and the other 5 route on the other.

 

[vbahuse]

Brian,

So the answer to my question is NO the cluster command switch does NOT have to do all inter-VLAN routing?

 

[vbahuse]

Burt,

Thanks for the hint (HSRP). I've read a white paper on using and configuring HSRP but it only gives examples when a routing protocol, such as EIGRP or RIP are used, and mentions that the routing protocol must converge before HSRP will start forwarding packets. My configuration currently uses Static routes for security reasons and I'm wondering if this is going to be a problem. That is, does HSRP work when only static routing is used?

Thanks

 

[burtsbees]

As far as I can remember it does...as long as the router knows what to route where. In the case of a routing protocol, the router has no clue what goes where or whom is where and why, until the protocols have all converged and "agree" ON ALL THE SAME OR RELEVANT INformation. Apparently, I accidentally hit the CAPS...sorry.
Sorry for being vague before...been real busy.

Burt

 

[brianinms]

Static routes work fine with HSRP. Additionally the cluster command switch does not have to route all the vlans. With HSRP you chose a preference for the interface. Which ever switch has the best preference for that vlan will be the router for that vlan. The cluster command switch is merely the switch that is the master for the cluster, which is just for that POS network assistant software.