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Sx500 series vPC peer-gateway command to counteract EMC packet reflection problem

Hi all! I'm living the SMB dream: I have several SG500-28p switches, and a EMC VNXe NAS. Both are fine machines, however they've got me stuck between a rock and a hard place.

I have the EMC VNXe system attached to a stacked pair of SG500 switches in L3 mode through a couple of port channels. Each port channel has members on both switches in the stack.

The problem is that the VNXe uses something EMC calls packet reflection, and that doesn't play nicely with vPC, which is what I believe the SG500 stack is using to make port channels work accross the stack. The end result is that packets don't route properly between vlans.

More info can be found about this issue in these articles:

I'm trying to get EMC to let users turn off packet reflection without going through a support call, and I was wondering if there was (or could be) an equivelent to the 'vpc peer-gateway' command on the SG500? That command (on other Cisco gear) would allow me to work around the problem on the switch end of things.



Sx500 series vPC peer-gateway command to counteract EMC packet r

Hi Daniel, to my knowledge the switch doesn't support such a command but one interesting idea may be to mess with the UDP relay (also known as IP heler). If you're having a hard time getting advertisements across layer 3 vlans then UDP relay may be able to help that along.

Those other 2 articles mentioned HSRP but I don't think that situation applies to you but the switch does support VRRP but I don't think it'd make any difference.

Please mark answered for helpful posts

-Tom Please mark answered for helpful posts
New Member

Sx500 series vPC peer-gateway command to counteract EMC packet r

The NX-OS 'vpc peer-gateway' command is useful when you have a pair of L3 Nexus switches running HSRP. Since all members of a vPC actively forward on all links, and with vpc peer-gateway you let the two NX switches share the mac address of the virtual HSRP active router which is the default gw, both HSRP peers will forward packets irrespective of who the active router is.

If the SG300 are stacked, they will appear as a single switch to the EMC device. You don't need HSRP on the SG300 since its a single switch. The IOS equivalent of vPC peer-gateway is not required here.

If you mean pair of stacked switches as in 2 separate stacks running HSRP, then ignore everything I said above.

One thing you could do is configure an Active Active HSRP design. You create 2 standby groups on each switch stack and make group 1 on switch 1 active and group 2 on switch 2 active..... refer