Is there a need to tunnel across MPLS?

Answered Question

I've seen customer configs on MPLS networks that just ran BGP to the provider edge MPLS router; and I've seen customer configs where GRE tunnels are built between sites over provider MPLS networks. I was hoping to get some opinions as to people's thoughts regarding the need to tunnel over provider MPLS networks.


THANKS!

Correct Answer by paolo bevilacqua about 9 years 9 months ago

In fact, I have not mentioned security, just plain GRE.


As I said, if MTU/total efficiency is not a concern, I would slightly prefer tunnels.

Just setup a single multipoint tunnel interface with the appropriate map or nhrp statements, and run you favorite routing protocol on it.


No need to coordinate anything with ISP so it's simpler. One thing you can ask, if if they support jumbo frames :)

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paolo bevilacqua Mon, 10/15/2007 - 10:41
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Hi,


with BGP, you can tell ISP which prefixes you have, so they can route them for you.


With tunnels, your routers sees each other directly. This comes at the price of a reduction in MTU and efficiency, but may become needed for example when using multicast.


Depending on the situation, you may find one or another way preferable.


hope this helps, please rate post if it does


So tunnels isn't necessarily for security, it is more for functionality? I'm about to deploy a 5-site MPLS network and BPG was not ordered so I was going to use static routes.

So, I guess by configuring tunnels, I'm going to be able to create a mesh topology? I know these are basic questions but I appreacite your opinion.

Thanks.

Correct Answer
paolo bevilacqua Mon, 10/15/2007 - 10:51
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In fact, I have not mentioned security, just plain GRE.


As I said, if MTU/total efficiency is not a concern, I would slightly prefer tunnels.

Just setup a single multipoint tunnel interface with the appropriate map or nhrp statements, and run you favorite routing protocol on it.


No need to coordinate anything with ISP so it's simpler. One thing you can ask, if if they support jumbo frames :)

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