HSRP or Hot Standby for WAN routers

[dejan.nedeljkovic]

Hi,

in close future i'll have to transition Frame Relay to L3VPN WAN links. I have two available routers and my dilemma is next:

1) i can connect my ISP's optical link directly to my primary router - in that case i can use simple hot standby (backup) router, with the same configuration as primary router, and manually switch cable if primary router goes down. Here, i have single point of failure which is primary router.

2) i can use L2 switch to transport ISP's vlan to both routers and use HSRP between them. But in this case i also have single point of failure which is the L2 switch, and if it fails i'll also have to manually switch cable to another switch!

What are the benefits/drawback of 1 or 2, your opinion?

Thanks in advance

[John Blakley]

2 would be the "better" solution even if you have a single point of failure. HSRP is going to require a /29 in order to work properly though because you'll need 1 for the standby on the WAN side and you'll need 2 more addresses for the physical on the WAN side as well. On your inside, you can assign whatever you like. The drawback of 1 is that it will require physical intervention. I'm not sure of your operating hours, but if you're in a 24/7 shop and you're the only person, it's going to be painful getting up at 2 in the morning to physically switch the cable or walk someone else through doing it. So the main drawback of 1 is that it's not automated and if you have hsrp configured on the lan (really pointless in this situation to do it on the wan side), all traffic will be blackholed until the connection is brought up on the outside interface.

The benefit to 2 obviously is that you have a much higher chance of that traffic automatically switching over, at least until your switch dies.

HTH,

John