Single CSS L3 link redundancy

[mloechel]

I have a single CSS11506 whose job is to load balance 4 web servers. I have two 1Gbps uplinks to the network - each goes to an L3 only 6506. I need enable the second link for failover purposes. How can I fail over to the second link with the following considerations in mind

1. Users still need to get to the same vip address(http) 2. No routing protocols enabled on the CSS 3. The rest of the network needs to understand how to redirect to the secondary link 4. The primary link comes back up after the link is restored 5. How to get around the rule that two uplinks cannot be in the same vlan

[d.parks]

"5. How to get around the rule that two uplinks cannot be in the same vlan"

I don't believe there is such a rule. You can have both uplinks configured with the same VLAN. This is normally used to bridge traffic "through" the CSS though. I've never tried dual-homing a CSS as I have dual CSS's in all of my production implementations.

I'd try configuring both uplinks for the same VLAN, and configuring an HSRP VLAN on your 6509's. The HSRP hello traffic would pass through the CSS to get to the opposite switch. i.e. treat the CSS like a regular access layer ethernet switch.

With VLAN autostate and/or interface tracking on the 6509, a failure of an uplink would cause the backup HSRP partner to go primary and the traffic would begin taking the other link.