The MPLS WG Archive

["Chris LaVallee" <clavallee@zumanetworks.com>]

I was already aware of the MPLSCP in the draft, so what I really meant to
ask was this:

1) Cisco-HDLC uses ethertypes, right ? Therefore MPLS will treat
POS/Cisco-HDLC as Ethernet.

2) Is there really a benefit to PPP-MPLSCP ?
Meaning, you could just use Cisco-HDLC or PPP-BCP. MPLSCP doesn't negotiate
anything.

I guess you do save a few bytes with PPP-MPLS data and if you're only MPLS
switching PPP to PPP, nothing has to be add/deleted or modified in the
packet.


Chris




> -----Original Message-----
> From: Eric Gray [mailto:EGray@zaffire.com]
> Sent: Tuesday, June 06, 2000 8:44 AM
> To: 'Chris LaVallee'; jleu@mindspring.com; David Wang
> Cc: mpls@UU.NET
> Subject: RE: Ingress LER in LDP
>
>
> Chris,
>
> 	Please read the draft:
>
>
> http://www.ietf.org/internet-drafts/draft-ietf-mpls-label-encaps-07.txt
>
> I'm not sure where you got the quote below (I seem to
> be getting mail messages from the MPLS mailing list
> in some sort of random ordering), but it is incorrect
> - the numbers given are not ether types...
>
> --
> Eric Gray
>
> > -----Original Message-----
> > From: Chris LaVallee [mailto:clavallee@zumanetworks.com]
> > Sent: Friday, June 02, 2000 4:29 PM
> > To: jleu@mindspring.com; David Wang
> > Cc: mpls@UU.NET
> > Subject: RE: Ingress LER in LDP
> >
> >
> > > -POS the ether type will be 0x8847 or 0x8848 (as oppsed to
> > 0x0800 for IP)
> >
> > This might be off topic, but...
> >
> > How do you get an ethertype over POS ?
> > I'm guessing it's Cisco-HDLC (which I know nothing about)
> >
> > PPP over POS has 2 other possibilities to carry MPLS
> > - Add a new CP (control proto) for MPLS
> > - Have BCP (PPP Bridging) carry MPLS
> >
> > Anyone have a preference / opinion on what people should use ?
> >
> > Chris
> >
> >
> >
> >
> > > -----Original Message-----
> > > From: owner-mpls@UU.NET [mailto:owner-mpls@UU.NET]On Behalf
> > Of James R.
> > > Leu
> > > Sent: Friday, June 02, 2000 11:43 AM
> > > To: David Wang
> > > Cc: mpls@UU.NET
> > > Subject: Re: Ingress LER in LDP
> > >
> > >
> > > On Fri, Jun 02, 2000 at 01:20:33PM -0500, David Wang wrote:
> > > > One related question: How a LSR distinguishes a labeled
> > packet from an
> > > > unlabeled packet?
> > >
> > > Depends on the medium:
> > > -ATM the VCC will contain a protcol type (AAL5Null requires this)
> > > -POS the ether type will be 0x8847 or 0x8848 (as oppsed to
> > 0x0800 for IP)
> > > -PPP has some PIDs assigned for MPLS as well (as does IP)
> > >
> > > Hope this helps.
> > >
> > > Jim
> > >
> > > >
> > > > -----Original Message-----
> > > > From: Eric Rosen [mailto:erosen@cisco.com]
> > > > Sent: Thursday, June 01, 2000 9:28 AM
> > > > To: Santosh Gupta
> > > > Cc: mpls@UU.NET
> > > > Subject: Re: Ingress LER in LDP
> > > >
> > > >
> > > > Santosh> Can someone tell me how to decide if a router is
> > > supposed to act as
> > > > Santosh> an Ingress LER for some particular FEC in MPLS domain ?
> > > >
> > > > People keep asking  this question, and I'm never quite sure
> > > just what it is
> > > > they are asking, because there isn't much of a mystery here.
> > > >
> > > > If a router received an unlabeled  packet which belongs to a
> > > particular FEC,
> > > > and the next hop for that packet supports MPLS, and the router
> > > is configured
> > > > such that it is allowed to do allow label imposition for
> > > packets in that FEC
> > > > with that next hop, then the router should impose the label
> > > assigned to that
> > > > FEC by that next hop.
> > > >
> > > > Does that answer your question?
> > >
> > > --
> > > James R. Leu
> > >
> >
>