The MPLS-OPS Archive

[Mathew Lodge <mathew@cplane.com>]

At 12:59 PM 3/15/2002 +0000, Vorley, Peter wrote:
>  
> I think I understand.  The
> 3Com RAS doesn't support MPLS-VPN, but you
> need to get the PPP session
> terminated somewhere that does?

For anyone who wants to try dial-up MPLS IP VPN, you can configure Cisco
RASes to be PE devices and it does work -- after a fashion. The problem
for all dial into MPLS networks (i.e. this is not vendor-specific, it's a
function of the way the voice network works) is the time it takes for BGP
to propagate the new routing info for the dial-up session once the user
dials up. BGP has to advertize the route to the new dial-up user after
they have connected and established a PPP session. This can take minutes.
You can't summarize the routes or pre-allocate IP address pools, because
you have no idea of the port where the call will appear.

This is why the recommended way of doing this is to use L2TP into a PPP
aggregation box that can perform route summarization and act as
PE.

Cheers,

Mathew

 
In this case, to the best of my knowledge, I would use L2TP and tunnel
the PPP session into the PE.
 
It's Robert Razsuk's config, so I'm not really comfortable posting this.
 
Robert reads and replies on this list, so hopefully Robert can re-post it
for you.
 
If you look through the archives you'll find it.
 
Please be aware that I haven't tested this though, but gives you an idea.
 
I saw that Cisco recently announced something L2TPv3, so you might
want to have a look and see if this is of any use...but haven't had chance
to look at it yet, so I don't know.  Does anyone else know?
 
http://www.cisco.com/warp/public/732/Tech/unified_vpn/
 
Thanks.

-----Original Message-----
From: Rakesh [mailto:rakesh.menon@tataisp.com]
Sent: 15 March 2002 12:39
To: Vorley, Peter; mpls-ops@mplsrc.com
Subject: Re: isdn fallback

Hi,
 
Thx Peter. Basically i wanted to know incase we give the isdn fallback, rather than on the PE,   on another n/w equipment like 3com RAS  then is it possible to go ahead with the VPN . In this scenario the customer will be dialling onto the PRI no. in the RAS. In this case how do we go abt VPN on fallback.
 
Rgds
rakesh

----- Original Message -----
From: Vorley, Peter
To: 'Rakesh' ; mpls-ops@mplsrc.com
Sent: Friday, March 15, 2002 2:50 PM
Subject: RE: isdn fallback

Hi,
 
Yes, I've tested it and it worked okay.
 
The only problem is that you need to do some spoofing to get around the delay of the
route being installed in the VRF (bgp scan-time is one way, but not ideal, playing with
a floating static and a dummy loopback is a better way)...Robert R posted a sample
config to this forum for getting around this a little while ago.
 
Could you please enlighten me why you think it might be different if dialing into the same
PE, versus a different one....perhaps I've missed something?
 
Cheers.
 
 -----Original Message-----
From: Rakesh [mailto:rakesh.menon@tataisp.com]
Sent: 15 March 2002 06:27
To: mpls-ops@mplsrc.com
Subject: isdn fallback

Hi ,
 
Has anybody tested an ISDN fallback to the PE for a VPN customer leased line on the same PE. Does the mpls vpn work on the isdn fallback .
 
Thx&Rgds
Rakesh <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
 

| Mathew Lodge                 | mathew@cplane.com     |
| Director, Product Management | Ph: +1 408 789 4068   |
| CPLANE, Inc.                 | http://www.cplane.com |