recently we had implemented MPLS on our network (a local ISP), rigth now we are thinking about extend mpls to our Internet Border Routers, some people told us this is not a good idea, but I really don?t see a good reason for this. ?Can someone advice us about this?, ?Is there any technical reason to not run MPLS on the border routers?.
Thanks in advanced for the help.
Actually, I can think of reason why to run MPLS on the Internet border.
With MPLS running on the core network, only the edge devices need to run BGP, the core P routers do not need to run BGP. This saves on the amount of memory required for your core routers.
There are many reasons why this could be done. As a matter of fact currently am doing a design for a Telecom customer where have suggested a similar approach.
We need to understand Internet can be provided in 2 methods in MPLS a) VRF Based b)Via Global RIB
The method of providing Internet over MPLS is called "BGP Free Core Method" as you core doesnt carry any internet routes, this also frees up links and other dedicated resources. Now to achieve these benifits its required to extend MPLS till your border routers.
There are implementation methods which achieve the same benefits without extending MPLS till the IGW's. But from operational point of view extending MPLS till IGW's would be personally recommended.
Having said that, there are no such technical drawbacks for extending the MPLS till the IGW. As far as security goes providing internet service without extending or extending MPLS has same level of security threat. So on a vis-a-vis comparision we see more operational & provisioning benefits rather than drawbacks.