Network Design question

TechGromitTechGromit GSEC, GCIH, GREM, Ontario, NY Member Posts: 2,051 ■■■■■■■■□□
I have two Cisco 6509 distribution switches, DS01 and DS02, with a 4 interface port channel between them. Now my understanding of failover for routers is when Router 01 can’t ping the DS01 and Router 02 can’t ping DS01 (or Router01) through the DS01 to DS02 port channel, The routers fail over with Router02 taking control making it the online and DS02 the primary distribution switch. And when DS01 comes back online, Router02 hands control back to Router 01 and the connection fails back, because Router01 is the preferred path based on priority.

Is my understanding correct here?

Now to my problem.

I’m replacing my 6509 Distribution switches with Cisco 4500X switches, there’s not enough ports on one 4500X to accommodate all the ports I had on the 6509, so I need two 4500X switches to replace each 6509 switch. So of if DS01 Switch 2 fails, I lose half my network, but the Router01 will not fail over, because it still sees a good connection to DS01 Switch1. So my question is can a router be set up to fail-over on multiple conditions? Where as if Router01 and Router 02 cant ping DS01 SW1 or DS02 SW2, fail over? If not can I have Router01 and Router02 ping DS01 SW2 instead of SW1, if SW1 is connected to SW2, SW1 must be up for SW2 to have a connection.

Another question I have is why is there four interfaces defined on my Port Channel between the switches? I thought this connection was for a heartbeat between the switches, is there really that much data being transferred between the switches to justify so many interfaces, or is this more for redundancy of the connection than actual data traveling this path?
Still searching for the corner in a round room.


  • networker050184networker050184 Mod Posts: 11,962 Mod
    Really no way to answer any of these questions. How is this ping set up some kind of IP SLA? Is this a VSS pair? No way to tell you how much capacity you need between the switches.
    An expert is a man who has made all the mistakes which can be made.
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