Can anybody tell me, is it best practice to have GM and WAN Agg routers combined in one router in DC, instead of having GM router behind the WAN Agg router ?
If the best practice to have WAN Agg router and GM router separated ? can you please tell me, why?
Thanks in advance!
I would say: it depends :)
If you have enough capacity on one router to do all the job - why not then, as high availability (in case of 2 routers) in the design should be achieved via routing protocol.
But if you need special QoS settings on Agg routers (that might be CE) or even a PFR, then it would be a good idea to dedicate a router for GM role.