[j-nsp] GRE & Bridging, is it possible with a Juniper box ?

[Will McLendon]

hopefully this works...first time posting to the list

one option might be to do an L2VPN or VPLS type solution where you tunnel the MPLS traffic over a GRE tunnel (only necessary if the intermediate network can't/doesn't run MPLS).  I think someone might have mentioned that previously as well.

The only problem you might run into is MTU and fragmentation related because of the extra overhead of the MPLS labels and GRE tunnel over the intermediate network.  If you leave the MTU at the defaults, packets with the DF bit set will be dropped and so far as I can tell (unless it changed with 10.0+), a J-Series or SRX can not clear the DF bit as it enters a GRE tunnel.  I think the higher end M / MX can though if you are using those.

However if you can raise the MTU of all the intermediate links, then you can alleviate that problem.

I have a config example of this working if you need one.


good luck, whichever route you choose


Will


************
On Jun 4, 2010, at 9:00 AM, juniper-nsp-request at puck.nether.net wrote:

Date: Fri, 4 Jun 2010 07:41:16 +0200
From: Peter Krupl <Peter.Krupl at siminn.dk>
To: Derick Winkworth <dwinkworth at att.net>,
	"juniper-nsp at puck.nether.net"	<juniper-nsp at puck.nether.net>
Subject: Re: [j-nsp] GRE & Bridging, is it possible with a Juniper box
	?
Message-ID:
	<4A66E92B3FBF8541A78CD11D1C0E3CFCC5CFDEA1AD at wp-ex02.hq.webpartner.dk>
Content-Type: text/plain; charset="us-ascii"

Hi Group,

Well I have a slight confession to make. When I initially asked the question,
it was based on the assumption that Cisco provided this. But they don't.
I had played with bridging over frame relay way back, and somehow this
became GRE in my mind. Sorry about the mistake.

So now im looking into L2TP as an alternative.

But the One-Access 1221 & 1424 are supporting ethernet over GRE.


Kind Regards,
Peter Krupl