Dual ISP Question
in [Cisco]
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From: J.Cottingim on 4 Apr 2006 00:06 Is there a way to have a router with an ethernet connection to two ISP's (and an inside interface of course) fail over from one ISP to the other when traffic stops flowing on the first one? * Neither ISP shares it's routing table. (it's not an option so don't suggest it) * Neither interface that faces the ISP's will go down (both ethernets attached to a switch) I was thinking of something with a route-map to a known "pingable" address - force it out primary ISP interface - but how do you make it fail-over to the backup ISP. Of course I could write a script that runs in conjunction with the route-map, but I'd really like to keep it on the router. Suggestions?? ___ ___ ___ ___ / \/ \ / \/ \ | ISP A | | ISP B | \___/\___/ \___/\___/ ¦R¦ ¦R¦ +-+ +-+ ¦ ¦ ¦ +--------+ ¦ +---¦myRouter¦---+ +--------+ ¦ ¦ +--------------+
From: Walter Roberson on 4 Apr 2006 00:20 In article <1144123681.755670.120070(a)j33g2000cwa.googlegroups.com>, J.Cottingim <jcottingim(a)yahoo.com> wrote: >* Neither ISP shares it's routing table. (it's not an option so don't >suggest it) >* Neither interface that faces the ISP's will go down (both ethernets >attached to a switch) >I was thinking of something with a route-map to a known "pingable" >address - force it out primary ISP interface - but how do you make it >fail-over to the backup ISP. Some platforms with some versions of IOS support ping-based detection of route availability. I do not recall any of the details; probably one of Vincent Jones' messages names the technology. Which platform and version are you working with?
From: Ken Gallagher on 4 Apr 2006 10:08 Couldn't you just set up 2 default routes, 1 with a higher administrative distance than the other? Say, ip route 0.0.0.0 0.0.0.0 dialer1 ip route 0.0.0.0 0.0.0.0 dialer2 220 I think that might work. Walter Roberson wrote: > In article <1144123681.755670.120070(a)j33g2000cwa.googlegroups.com>, > J.Cottingim <jcottingim(a)yahoo.com> wrote: > >* Neither ISP shares it's routing table. (it's not an option so don't > >suggest it) > >* Neither interface that faces the ISP's will go down (both ethernets > >attached to a switch) > > >I was thinking of something with a route-map to a known "pingable" > >address - force it out primary ISP interface - but how do you make it > >fail-over to the backup ISP. > > Some platforms with some versions of IOS support ping-based > detection of route availability. I do not recall any of the details; > probably one of Vincent Jones' messages names the technology. > > Which platform and version are you working with?
From: Merv on 4 Apr 2006 10:28 the feature you want to use is known as "Reliable Static Routing Backup Using Object Tracking" http://www.cisco.com/en/US/products/sw/iosswrel/ps5413/products_feature_guide09186a00801d862d.html The IP addresses you ping should be somewhere on the ISP's core links, not just on the ISP's POP routers as the POP may become isolated from the rest of the ISP network.
From: J.Cottingim on 4 Apr 2006 14:29
The weighted routes wouldn't work as interface won't be going down to remove the static route. |