[c-nsp] 6PE

[Mathieu Paonessa]

Hi!

On 8/3/11 3:28 AM, Mark Tinka wrote:
> On Wednesday, August 03, 2011 03:55:43 AM waseem thaer 
> wrote:

>> I'm interested in the 6PE solution to offer IPv6 for
>> customers, for those of you who have checked this
>> solution in production network please share your
>> experiences and what are the hardware and software
>> configurations you have??
> 
> It is a valid approach in operationalizing v6 in your 
> network, and has been used quite extensively. But I'd say 
> that if you had the choice, don't run it.

We've been running 6PE since late 2007 and are very happy about it.
Here's why I don't agree with you:


> 6PE depends on MPLS, which depends on IPv4. If your v4 dies, 
> your MPLS dies, your v6 dies.

There's two different v4 world here:
	- We run IPv4 + IGP + MPLS with only the P/PE loopback and interco
subnet. This keeps a very compact internal routing table and allows all
our core infrasctructure not to be visible from outside.

	- "Internet" IPv4 is running inside a VRF like any other MPLS IP/VPN.
Any routing issue on that IPv4 Internet world would not affect our IPv6
infrastructure.


> If your MPLS dies, your v6 dies.

For many network these days, if your MPLS dies, your network dies.


> Plus, 6PE is yet another tunneling technology through which 
> to run your v6 network.

Sure but what's the issue there? If you're running MPLS you're tunneling
in v4 ou v6 anyway.


> We have 2 large MPLS networks, but have resisted 6PE which 
> always seems easier (and makes the MPLS zealots happy 
> because it's yet another thing MPLS can wrap itself around).

Damn, I must be one of those zealots :)


> Native/dual-stack is always best. If you can do it, prefer 
> that. It's cleaner and less dependent on many other things.

Depending on what your network looks like, not always.
For example if you run OSPF, you'll have to run two IGP so that makes
twice the work when deploying new devices. Not saying that I've seen
many people modifying their ospf cost in v4 and forgetting to do it in
v6 when changing their routing topology.


> But if 6PE is your only option (I don't see how since 
> anything decent enough to run 6PE these days can run native 
> v6), then by all means, go ahead :-).

One of the reasons we went for 6PE back in 2007 is that we still had
some Engine 2 GSR cards on the network and those are not able to do IPv6
in hardware. There was no way on earth that we would run software IPv6
on our core and had no budget to renew the core at that time.

I've done a presentation during the last FrNOG meeting about our 6PE
experience. The talk is in french but the slides are in english
(http://dai.ly/kRr5WE) if that could help.

Cheers,

--
Mathieu Paonessa