SD-WAN migration

[davinci]

Within my customer line of business, I manage a total of 9 Cisco routers.   EIGRP runs within internal LAN and EIGRP over DMVPNs between the sites.  I also run eBGP on 2 of those routers toward the Cloud SP.  How would I implement SD-WAN given the widespread use of EIGRP?  FYI, there are also 2 other lines of business that run EIGRP as their IGP for the same company but I don't manage those network devices.

[Francesco Molino]

Hi

Can you give us more details please on the sd-wan solution you want to implement and what dynamic routing protocol it supports?

[davinci]

We haven't decided on an SD-WAN vendor but I am aware of the fact that nobody--including Cisco Viptela--supports EIGRP within SD-WAN implmentation.  As mentioned above, I use EIGRP and BGP.  The purpose of this thread is to brainstorm on a migration from EIGRP to OSPF or some other strategy. 

[Francesco Molino]

Ok it was just to know to found out the best solution.
You're right, all of them doesn't support EIGRP. Some of them support OSPF but ALL of them support BGP.
You need to be careful while configuring BGP because if you treat SD-WAN sites with different AS you gonna use ebgp and AD will be better than EIGRP then you can face some asymmetric issues if traffic goes over bgp for some and return through EIGRP (while full config not completed).
I would start moving to BGP by modifying the AD of ebgp to be high than EIGRP. Then you can configure everything without any impact. As soon as your config is fully done and you make sure you learn every prefixes in your BGP table, you can start lowering down as default the ebgp AD to make sure traffic uses it instead of EIGRP.
When this is done, you can switch off EIGRP.

There are many approches and this is one is quite simple with no impact.

[elesani]

From my experience, during the integration phase, treat your SD-WAN Overlay network as a separate AS within your network and build up the routing through BGP sessions with rest of it. 

Also, beer in mind that EIGRP is not a supported routing protocol in Cisco SD-WAN (old Viptela) platform at the time of writing this message.

/Ehsan

[elesani]

From my experience, during the integration phase, treat your SD-WAN Overlay network as a separate AS within your network and build up the routing through BGP sessions with rest of it. 

Also, beer in mind that EIGRP is not a supported routing protocol in Cisco SD-WAN (old VIPTELA) platform at the time of writing this message.

/Ehsan