04-09-2010 05:23 PM - edited 03-04-2019 08:05 AM
At present I have a network consisting of Edge routers C and D being connected to the Internet via Routers A and B
the default route for users attached to Router C is via Router A and the default route for users attached to Router D is via Router B
The EIGRP ensures their is always a default route available if a primary connection fails.
It has now been decided to host services outside the Corporate zone, but using the Corporate address space on Router E. Our service provider
has agreed to install static routes on Router A and Router B pointing to 172.16.48.0/22 so the outside world is properly directed,
My problem is that I want 172.16.48.0/22 to be part of EIGRP 1 and appear in the routing tables so it can be redistributed into EIGRP 2
but if the primary connection between Router C and Router A fails I still want 172.16.48.0/22 to be visible to users in EIGRP 2 area
I have included a drawing Layout1.pdf
what are my options ?
with thanks G
Solved! Go to Solution.
04-12-2010 06:15 AM
Hi,
Multiple eigrp AS is not recommended. Because multiple eigrp AS will require mutual redistribution and that can cause potential loop. Besides, using multiple AS cannot stop query anyway. A single EIGRP AS with summarization is the best practice.
With proper configuration, GRE should work as well. However GRE usually add some other problem because of the MTU or high CPU, so I would not use GRE if there is other solution.
HTH,
Lei Tian
04-10-2010 07:21 PM
Hi g.peart,
I prefer static route.
Have a static route on Router C for network 172.16.48.0/22 next hop point to Router A with track option, so that static route will be removed when link fails between Router C and Router A. Advertise this route into EIGRP on Rouer C.
On Router D configure a static route for network 172.16.48/0/22 next hop point to Router B with AD higher than 170, so this route will be less preferred than EIGRP route. Advertise this route into EIGRP on Router D.
One question, why do you use 2 EIGRP AS?
HTH,
Lei Tian
04-11-2010 04:26 AM
Thanks, that looks the way to go and probably a lot more stable then GRE tunnels (would GRE tunnels even work ?) I'll test build and see.
As for the EIGRP bit that was going to be another issue, but here goes anyway, Router D is actually
part of a RIP network that I am going to convert to EIGRP via the big bang approach,.( rewrite the start-up configs
on all the RIP routers, then reload and wait for convergence)
The drawing shows layout after conversion, I was going to make all the routers that were in 172.17.0.0/16 part
of EIGRP 2 area, so Router D which is the only EIGRP speaking router at present in 172.17.0.0/16 will become
part of EIGRP 2, I didn't want to introduce instability into 172.16.0.0/16 if it goes wrong so kept seperate EIGRP AS,
would good practice dedicate all the corporate space as one EIGRP AS ?
04-12-2010 06:15 AM
Hi,
Multiple eigrp AS is not recommended. Because multiple eigrp AS will require mutual redistribution and that can cause potential loop. Besides, using multiple AS cannot stop query anyway. A single EIGRP AS with summarization is the best practice.
With proper configuration, GRE should work as well. However GRE usually add some other problem because of the MTU or high CPU, so I would not use GRE if there is other solution.
HTH,
Lei Tian
04-12-2010 07:27 AM
Thank you for the advice, I'll amend my design as necessary
and go with a single EIGRP area, along with the floating static routes.
If I have time I'll test build using GRE tunnels as well, just to see what would happen.
regards
G Peart
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