Floating Static routes and RIP

MrXpert

I've been playing around with a network on Packet Tracer and have set up three routers called Boston, GB and HQ They are all directly connected to each other via serial links.

Off each router is their own switch and a couple of host PCs per each LAN. Initially I setup RIP on all routers and it was working fine but then i thought i'd try adding a floating static route in the hope that it would be added to the routing tables and be there as a backup. For example Boston knows how to get to GB's LAN via a RIP learned route and it achieves this with the default Admin distance of 120. But i thought what if the serial link goes down between these two? Boston wont be able to talk to GB. So i then configured a static route which told Boston he can get to GB's LAN by sending it to HQ's router. The entry for this new static route appeared in the Boston routing table but the original RIP learned one to GB's LAN had been deleted. I waited a minute and tried the "show ip route" command hoping it would be updated but still nothing. It appeared to me that the Boston's routing table had rejected the RIP update because the static route had a lower admin distance(1) so therefore was more trusted.

I then tried changing the static route to a higher admin distance of 125 but this time the static route didn't show up in the out put of "show ip route" and the RIP route to GB's LAN was showing now instead. Finally i made the static route admin distance of 120 and instead of it keeping both this route and the RIP one it preferred the static one and it got rid of the RIP one.

I had hoped creating a floating static route would work as it states in the CCENT exam cram book it can be done using the ip route {destination network} {subnet mask} **** of next hop router or egress interface} {optional custom admin distance}

Can anyone suggest where i have gone wrong please?

pham0329

I think you're a bit confused with what a floating static route is. As you said, a floating static route is a backup route, meaning it only gets installed in the routing table when the primary route goes down. That's what you observed when you changed the AD of the static route to 125. It "floats" (is that why it's called a floating route??) in lala land until the other one fails.

What you're looking to accomplish is load balancing and although I've never tried it, I don't believe you can load balance 2 routes, learned from 2 different routing protocol/source.

The process for a route to get installed in the routing table is

• If there are multiple routes, with the same network/mask, the one with the lowest AD is installed
• If there are multiple routes to the same network/mask, with the same AD, the one with the lowest metric is installed
• If there are multiple routes to the same network/mask, with the same AD/metric, up to 4 (by default) are installed in the routing table.

base2

I agree, sounds like you are doing it right. Kill the RIP route and you should see the static route pop up into the routing table. Dont forget to make sure the other router has a route back for the return traffic (probably will need to float a static on that side as well).

MrXpert

Sorry for the late reply but just want to say a big thanks for your help! you are right, I was doing it correctly, it was just "floating" around and I didn't realise it. It became apparent after the rip learned routes died. It was a good feeling seeing the floating route appear in the table.:)