Peer-gateway in VPC Config with HSRP

[sandevsingh]

Hi, we are planing to run HSRP on our Nexus 5ks (with L3 card) and we use VPC to connect the downstream UCS - Fabric Interconnects to the 5ks. I was wondering if the peer-gateway command is required under the vpc domain config? When you use HSRP with VPC, both the active and standby HSRP peers can forward layer3 traffic, isn`t that the same that peer-gateway would achieve?

[Oleksandr Nesterov]

Hi

Here is description of main function of "peer-gateway":

Beginning in Cisco NX-OS Release 5.0(3)N1(1b), you can use the peer-gateway command to allow Cisco Nexus 5500 Platform switches to perform Layer 3  forwarding if the destination MAC of the incoming packet is the MAC of  its vPC peer switch. The  peer-gateway command avoids forwarding such packets to the vPC peer link.

So without this command switch will send all packetd destined to "vpc peer's mac address" through peer-link. And "peer-gateway" allow to n5k route such packets.

http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/operations/n5k_L3_w_vpc_5500platform.html#wp998473

This command is not required - but it improves network performance, allows traffic be balanced better etc...

HTH,

Alex