Hello
We are currently designing Layer 3 to the edge EIGRP solution for our customers. The network is a hybrid of collapsed core (Core to access) as well as a three layer design (Core/Distro/Access) for connectivity to the Data Centre, Internet, Wireless Blocks etc.
The core of the network contains two 6509-E switches interconnected on a Layer 3 Port channel (no VSS). Access Layer switches (3750-X series running Stackwiseplus protocol) connect to the core switches over p2p routed links and Distribution layer switches (3750X stackwiseplus) provide connectivity to the Data centre, Internet, wireless blocks etc.
The access and distribution switch stacks(Cisco 3750-X) are set up with two or three member switches with uplinks multihomed to the primary and secondary core switch with each uplink included in EIGRP. In each of the stacks, one of the switches controls the operation of the stack, which will be the stack master.
As the Cisco Stackwise architecture is not SSO-capable but NSF aware, all Layer 3 fuctions must be re-established during a master switch outage. To minimize control plane impact and improve Layer3 convergence, uplinks should be diverse and originate from the member switches instead of the Master switches in the respective stack. This is as per Cisco recommended design solution.
My question is as follows:
The above solution can be setup if there are more than two switches in the stack. i.e. uplinks are configured on the backup member switch modules.
1.But what about stack with two switches..Which switch should be set up as the Master for a two member stack with uplinks to the core primary and secondary from each switch(Master and Backup)
2. For Layer 3 routing, does the routing takes precedene over switch failures? Say for eg. In a two member stack, the master switch with uplink to primary fails, does EIGRP provide a fast convergence to route traffic via backup secondary and does not wait for the control plane on the switch stack to converge? All the access to core links will be set up for ECMP.
Thanks and Regards,
Mohan
