I have asked following question related HSRP setup and here is the diagram and detail:

HSRP issue both device active stats

Question: I have cached on our cacti monitoring, traffic is flowing asymmetric, currently SW1 is active in HSRP.

In cacti its showing following going out from SW1 and traffic coming in from SW2, I believe who ever is active in HSRP should send and receive traffic on same switch right?

SW1 - Traffic going out 
SW2 - Traffic coming in


I have no idea which ISP router is active R1 or R2, what if ISP side R2 router is active one in HSRP?

  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide your own answer and accept it.
    – Ron Maupin
    Aug 6, 2017 at 23:00

1 Answer 1


No. HSRP defines the first hop for hosts sending traffic off the LAN. it has nothing to do with how traffic coming from somewhere else is routed, and any router connected to the LAN will put it on the LAN, otherwise you are adding inefficiencies. HSRP is on the LAN, not in front of the LAN in the routers. The routers communicate with HSRP messages on the LAN, and you may or may not have any other connections between the routers, so they would have no way to send the packets to the other router, anyway.

The diagram shows HSRP on a link between the routers? That doesn't seem right since there are no hosts on that link. HSRP is only for hosts with configured gateways.

What you really want to do is to make sure that your HSRP priorities (higher is better, like bowling) line up with your STP priorities (lower is better, like golf), so that both HSRP and STP want to deliver to the same place, otherwise you can get inefficient switching where frames are sent to the root switch, then need to be sent back to a different switch for routing.

  • Ron - How are you? good to see you again. You provide me that solution right while ago. My HSRP is setup between me and ISP if you see my picture. we don't have any hosts there. I am also surprised how ISP sending traffic on SW2 switch because that is standby, things working fine but only concern is why asymmetric, if possible can we talk on private chat?
    – Satish
    Feb 19, 2016 at 17:01
  • I have a conference call that just started. It will need to wait for a while.
    – Ron Maupin
    Feb 19, 2016 at 17:03
  • Ron - sure let me know when you free.
    – Satish
    Feb 19, 2016 at 17:07
  • Ron - question, what if ISP side HSRP R2 is active in that case they will send traffic on SW2 right?
    – Satish
    Feb 19, 2016 at 17:20
  • Whichever router receives the inbound traffic has the best route to the destination as far as the outside is concerned. Since that router is connected to the LAN that router will put the traffic on the LAN. It makes no sense to send the traffic across the LAN to the other router so that it has the honor of placing in the LAN. HSRP is for hosts to send off-net traffic to. It has nothing to do with the routing tables of routers.
    – Ron Maupin
    Feb 19, 2016 at 20:08

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