OSPF or EIGRP for DMVPN ?

[Saquib Khan]

Hi DMVPN Gurus,

a) I am going to be deploying a 90 - 200 spoke DMVPN sites and could go. It is going to be a dual hub configuration. Some of these sites will just be dmvpn spokes,  and others, the dmvpn is going to be a backup tunnel to the our MPLS cloud. Currently the MPLS is running over OSPF, which is getting redistributed via BGP in the ISP world, therefore the routes I get are external E1 OSPF advertised routes.
b) I would also like the dual hub to have a dmvpn vpn tunnel between them, so as a backup between the hubs incase the MPLS WAN drops.

Requires some good tested advice or whether to use EIGRP or OSPF.
if anyone who has had similar thoughts, hands on experience with a similar deployment, please share your pros and cons regarding EIGRP v/s OSPF

Questions:

1) What would be the recommended protocol for 90 to 200 tunnels, but keeping in mind these sites can grow so scalability is key ?
2) With External Type 1 OSPF routes being advertised, the E1 routes are required to be primary and the DMVPN redundant. Which routing protocol can handle this best with EIGRP being metric 90 and OSPF 110. What is the best way to influence metric in this scenerio ?
3) Out standard is using OSPF, therefore would  prefer to stick with OSPF for DMVPN, but handling internal v/s external routes could be a challenge as DMVPN would be internal routes ?
4) OSPF could have scalability issues, metric preference issues ? What are your thoughts ?

Thanks and much appreciated

[Marcin Latosiewicz]

Hi,

Disclaimer: This is my personal opinion not a statement from Cisco.

Let me start by saying that I do not prefer one or the other, and always suggest using them depending on requirements.

The best would be to use BGP - it scales best and allows you to do all those neat tricks that BGP can do.

For a large flat network EIGRP + EIGRP stub on spokes scales pretty neatly. You can change AD the way you want on devices to suit your need.

If you want to stick to OSPF (with MPLS still there, and no possibility to change domain id) - following trick comes to mind:

- redistribute networks as E1

- high cost on tunnel interfaces

(other "tricks" exist)

I would say last scenario is an overkill when EIGRP witch changed AD will work just as well. 

Marcin

[skhan]

Thanks Marcin,

Good points thanks.

I have the lab running on EIGRP quite well with OSPF redistribution to the LAN. Will be testing with MPLS redundancy which is running OSPF and validate how E1 routes dictate. Obviously looking for better alternatives and scalability