vpc
I'm trying to figure out scenarios in which one would use single homed, dual homed and double sided vpc and what benefits each topology would have?
I can already see that dual homed vpc would have better redundancy and more bandwidth than single homed. What other advantages and disadvantages exist between each method?
As the firewalls aren't part of a vPC they won't be part of the normal vPC loop prevention.
The loop prevention only states that a packet cannot ingress on the peer link if it is destined to go out another vPC enabled port.
Not too sure on the multicast front as we don't use it in our environment and I haven't really looked into its behaviour on the 7K's.
Usually if you are running a routing protocol down on the switch stack the recommended design would be to not have it as a member of a vPC and just use OSPF to give you the same advantages that vPC gives you at L2.
First of all there is a big difference between VSS and VPC where Nexus vPC is introduced with Nexus 2,5 and 7K. The vPC is actually eliminate the need of STP on the member vPC ports and allow for efficient load sharing capabilities .The VSS on the other hand is a feature introduced with Cisco 6500 catalyst, its basically combines the Back plane throughput of the two systems which allows for high forwarding rate between ports, it also simplifies the management by making two physical switch operate as one logical Switch(like stack wise in 2960,3750 series). enter link description here
Second there is a difference between VSS and other redundancy protocoles like HSRP and VRRP , where VSS operate so far like Stack wise in 2960 and 3750 series single IP will manage all the chassis but in HSRP and VRRP you had to assign each chassis one IP and then gave them the Virtual IP but one drawback that VSS can't be supported in all chassis
Finally if you just want to obtain redundancy between chassis for fail over purposes you can run VSS,HSRP,VRRP for cisco IOS and VPC for Nexus. if you aim to also obtain single management IP you need to run VSS only but it is depend on the chassis
Best Answer
You kind of answered it yourself. The advantage for each is an increased level of redundancy. The advantage of vPC is that is provides link redundancy as well as chassis redundancy. A dual-homed connection would be used for end devices that support port-channeling. For double-sided you of course need the downstream devices to also support vPC, such as a core layer of Nexus 9k connecting to a pair of Nexus 5k.