[c-nsp] Layer 3 Core

[Paul Stewart]

Just curious on this topic... searching docs and can't find answer...

Can you transport VTP over l2tpv3?

Paul
 

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Shane Amante
Sent: Thursday, April 05, 2007 2:58 PM
To: Voll, Scott
Cc: Stephen Backholm; cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] Layer 3 Core

Another option to consider is, instead of enabling MPLS forwarding over your
core, look at encapsulating Ethernet over MPLS inside L2TPv3.  This would
require you to enable MPLS at the edge(s) of your network, but still run
native IP forwarding in your core.

Overall, I would favor MPLS forwarding or L2TPv3/UDP/IP forwarding of EoMPLS
packets between your locations because you get protection & restoration in
the core, since that is a natural property of IP or MPLS. 
  In addition, you gain the benefit of fate-sharing and similar fail-over
times for Layer-3 & Layer-2 connectivity between the two locations.  One
downside of L2TPv3, to keep in mind, is it's not ubiquitously available in
HW on all platforms, (e.g.: 6500/SUP720), whereas native MPLS is more widely
available.

I think if you attempt to stand-up a single VLAN over the core, and you lose
a link in the core, you're out-of-luck.  On the other hand, if you attempt
to set-up diversely 'routed' VLAN(s) over the core, then you have to
consider running STP between locations or start looking at other more
complicated methods to provide protection between both locations.

-shane



Voll, Scott wrote:
> Why add complexity..... I'd just trunk.
> 
> Scott
> 
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net 
> [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Stephen 
> Backholm
> Sent: Thursday, April 05, 2007 9:38 AM
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] Layer 3 Core
> 
> Currently where I work we run a complete Layer 3 network core. This 
> decision was made in order to keep Spanning Tree Protocol, ACls, QoS, 
> and Policing out of the core and at the distribution layer. This has 
> worked well for us, but we have a need for a few of our server VLANs 
> to be in opposite geographic ends of campus for redundancy. These 
> servers run as clusters and require Layer 2 connectivity between them, 
> so in other words we need Layer 2 connectivity across our Layer 3 core.
> 
> 
> Here is the question.
> 
> Would it be better to solve this problem with MPLS or just trunk the 
> handful of server VLANs across our core?
> 
> 
> Your thoughts and/or suggestions are appreciated.
> 
> Regards,
> Stephen Backholm
> 
> 
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