Subject: MPLS tagging over PPP

From: Che min Hsieh <[email-masked]>
Date: Fri, 16 Mar 2001 18:05:46 -0500

I am wondering if there is any RFC that describes  the MPLS tagging over
PPP.

The closest  one I can find is in the  "MPLS  Technology and
Applications"  book by Bruce Davie and Yakov Rekhter,  Section 4.3  "Tag
Encapsulation on Non-ATM links",  page 113,  2nd paragraph,
  " On point-to-point subnetworks, packets that carry tags are
identified by the PPP protocol field ....".  In which RFC is this
documented? Or ,  it is a  proprietary extention from Cicso.

Is there any PPP extention that allows multiple instances of NCPs over a
single LCP?  (let's say multiple BCPs over a PPP link)

Any information about this matter is appreciated.

Thanks.

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From: James Carlson <[email-masked]>
Date: Sat, 17 Mar 2001 00:38:55 -0500 (EST)

> I am wondering if there is any RFC that describes  the MPLS tagging over

Try RFC 3032.  Section 4 describes MPLSCP and the encoding used for
PPP.

> single LCP?  (let's say multiple BCPs over a PPP link)

You want to run multiple copies of a single NCP over a PPP link?  No,
that's not possible.

Perhaps if you can describe the application, someone here can give a
better answer.

-- 
James Carlson                                  <[email-masked]>
"PPP Design and Debugging" --- http://people.ne.mediaone.net/carlson/ppp

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From: Che min Hsieh <[email-masked]>
Date: Mon, 19 Mar 2001 08:49:45 -0500

Thanks.

> Perhaps if you can describe the application, someone here can give a

Let's say a service provider is providing Remote MAC bridge service to
customers.

Customer A has LAN port A1 of 10/100bt , WAN port WA1,  remote WAN port WA2,
and LAN port A2 of 10/100bt.   The WA1, and WA2 are connected by PPP on POS
over OC3c

Customer B has LAN port B1 of 10/100bt, WAN port WB1,  remote WAN port WB2,
and LAN port B2 of 10/100bt.   The WB1, and WB2 are connected by another  PPP
on POS over OC3c

BCP, LCP, POS will be fine  in this case.

But if the service provider says,  it is a waste of  WAN bandwidth.   The LAN
 port bandwith  is 100 meg , but the POS is 150 meg.  How about let them
share the same OC3c path,  and have some statistical gain,  if possible.

 There needs to have a multiplexing/demultiplexing scheme to distinguish
which flow of traffic it is.   MPLS label seems not able to help.   It has
the addr, control, protocol (=mpls), label, network header ( =IP), ...
What we need is after the label, it carries the MAC frame.

---

From: James Carlson <[email-masked]>
Date: Mon, 19 Mar 2001 11:29:33 -0500 (EST)

> and LAN port B2 of 10/100bt.   The WB1, and WB2 are connected by another  PPP

OK.

> share the same OC3c path,  and have some statistical gain,  if possible.

I'm not sure I follow you here.  How do you get a single STS-3c from
the provider to terminate at multiple sites?  Aren't STS-3c paths
point-to-point?

In any event, read the BCP document (RFC 2878).  It includes VLAN
support, which will do approximately what you're asking.

(What you're asking doesn't entirely make sense to me.  As a customer,
why do I want Ethernet bridging service?  IP connectivity would seem
to be much better, and avoids issues like this.  But, then, they're
your customers ...)

> What we need is after the label, it carries the MAC frame.

If you use MPLS, you can stack any number of labels to get the tunnel
multiplexing to work the way you want.  If you need more information
than that, I'd recommend hiring a consultant.  Network design is a
little hard to do by email, and is certainly not appropriate for an
IETF mailing list.

-- 
James Carlson, Internet Engineering       <[email-masked]>
SUN Microsystems / 1 Network Drive         71.234W   Vox +1 781 442 2084
MS UBUR02-212 / Burlington MA 01803-2757   42.497N   Fax +1 781 442 1677
Second Edition now available - http://people.ne.mediaone.net/carlson/ppp