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Internal Routing Protocol?

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Mar 17th, 2006
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I have a Gateway 7206VXR, Core 7206VXR, and 6 6509's running Sup2U-MSFC2's. I am running BGP on my Gateway router and it is routing our /19 to the Core. I am doing layer3 switching on all my 6509's.


The problem is routing between my Core and all my MSFC2's. Right now, I have a VLAN that I specfically use for routing and I have a sub-interface of my Core and VLAN interfaces on all my MSFC's in that "routing VLAN 15". On all my MSFC's I have 20 - 30 VLAN interface's all with differnet classless subnets. Right now, depending on the MSFC2 that does the routing or cef switching I should say, for that particular VLAN, I have to create a static route to that MSFC2 IP in VLAN15 from my Core. As you can imagine I have a ton of static routes on my Core router.


What I would like to do is use some sort of Intra-Area or Internal routing protocol between my Core and MSFC's, so that I can get away from all this static routing on my core. I was looking in to OSPF, but don't know to much about it.


Is it possible that sombody could help with deciding on an Internal routing protocol to go with, and also get some sort of example on how this would be achieved.


I also attached a small example of how my network looks. Mind you, I did not put all my VLANS and subnets on on the MSFC's as it would be too large. You will get the idea though.


Thanks for the help!



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Richard Burts Fri, 03/17/2006 - 12:25
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Ethan


I have looked at the diagram that you posted. I agree that trying to do the routing with static routes gets quite complicated and does not scale well. Running some interior routing protocol to route within your network would be a good idea. I suggest that the two protocols that you should think about most are OSPF and EIGRP. I think that either of them could work quite well for you. If you know either of them better than the other, then I would go with the one that is a bit more familliar. If neither of them is familiar then I would tend to use EIGRP in this network.


HTH


Rick

eknell Fri, 03/17/2006 - 14:12
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Thanks, Rick. I will look into EIGRP then. Do you happen to know, if you can provision EIGRP while all your static routes are in place. As far as the migration process goes will this take anything down or can you just bring EIGRP up, and start deleteing static routes off the Core??

vladrac-ccna Fri, 03/17/2006 - 13:45
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Hello there,


I would follow the last post advice, as EIGRP is quite simple to configure (and you dont need to care much about areas, DR, network types...).


so, just choose an AS number and configure your router/swiches with EIGRP:


Something like:


router eigrp 100

network 64.0.0.0

network 172.16.0.0

no auto-summary


For the default-route, you could use a summary-address on the core router like:


interface Gigabitethernet 0/1.15

ip summary-address eigrp 100 0.0.0.0 0.0.0.0


Please let us know, what you have decided.


Vlad



eknell Fri, 03/17/2006 - 14:19
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As far as my MSFC's go, since some service differnet networks that others, will I just have those networks in my "router eigrp" config? Or will I have the exact same config on all my MSFC's as well as my Core and EIGRP just knows what actual MSFC the subnet is coming from? Most of the subnets on the MSFC's are /30's, /29's, and /28's.


I appreciate the help!

Richard Burts Fri, 03/17/2006 - 14:53
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Ethan


There are some options in configuring EIGRP. You can configure network statements with masking so that you can specify individual interfaces (which would make the configuration of each of your MSFCs be unique) but you can also configure EIGRP with a simple network statement with no mask. This would make the configuration of each MSFC alike and this is what I would do in your case. In this situation each MSFC will dynamically learn which subnets are reached through which MSFC. The configuration might look something like this:

router eigrp 123

network 64.0.0.0

network 172.16.0.0

no auto-summary


To answer a question from your earlier post: you can configure EIGRP while there are still static routes. Since static routes have a better administrative distance and are preferable in the routing table they will be used with EIGRP as a complementary source of routing information. As you gradually eliminate the static routes those subnets should be advertised by EIGRP and those subnets would still be reachable.


HTH


Rick

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