1 Feb 2006 09:24
RE: Generic PW - Is there a need?
Sasha Vainshtein <Sasha <at> AXERRA.com>
2006-02-01 08:24:22 GMT
2006-02-01 08:24:22 GMT
Andy (and all)
Lots of thanks for a prompt response.
I agree with you that adapting the 2684 approach would be quite straightforward.
I would also like to note that, IMHO, such a generic packet PW would not, per se, solve the problem of carrying meaningful "IP pseudo-wires" between disparate Layer 2 attachment circuits (assuming that this is one of the objectives pursued). The following points needs special attention
ARP: mediation vs.
- The latter could operate in the data plane but seems to be restricted to the case when the two ACs represent interfaces of the same type (P2P, NMBA or LAN)
- FRF8 can be adapted where where applicable
- IPCP translation for PPP-based AC requires special consideration
- The former can operate between interfaces of different types but seems to involve dependency on the control plane (see draft-ietf-l2vpn-arp-mediation-04)
Hopefully these notes will be useful.
From: Andrew G. Malis [mailto:andymalis <at> comcast.net]
Sent: Tuesday, January 31, 2006 7:25 PM
To: Sasha Vainshtein
Cc: 'Stewart Bryant'; Danny McPherson (E-mail); benjamin.niven-jenkins <at> bt.com; pwe3 <at> ietf.org
Subject: RE: [PWE3] Generic PW - Is there a need?
Yes, I was about to send out an email with the same conclusion. It should be relatively straightforward to adapt one of these two (probably 2684, given its header word alignment vs. header byte alignment in 2427) for this purpose. I've always been of the opinion that we should have included a PID in the MPLS header way back when, but that was the minority opinion at the time.
At 1/31/2006 06:24 PM +0200, Sasha Vainshtein wrote:Stewart, Danny and all,
Are we possibly speaking about something like "multiprotocol interconnect over PW" similar to multiprotocol interconnect over FR (RFC 2427/STD 55) or multiprotocol interconnect over AAL5 (RFC 2684)?
From: Stewart Bryant [ mailto:stbryant <at> cisco.com]
Sent: Tuesday, January 31, 2006 4:54 PM
To: benjamin.niven-jenkins <at> bt.com
Cc: pwe3 <at> ietf.org
Subject: Re: [PWE3] Generic PW - Is there a need?
benjamin.niven-jenkins <at> bt.com wrote:You need a standard method to multiplex a number of protocols over the
Danny, It is not entirely clear to me what the proposal you are making is or the motivation behind it. Are you stating that to support IPLS, transport of MPLS PWs over a PW etc. that a new control word format/encapsulation is required and this document will specify such a control word format? If so, what is deficient/missing in the current control word formats?
PW. It's not always the case that the only protocol that needs to be
carried is IP. You might want to carry IP + ISIS, or IP + MPLS etc.
We could do this by defining a canonical data-link type, or by
adding a PID to the PW. How we do it is a WG decision.No, we think that there is a need to carry multiple types over the same PW.
Or is it to just essentially combine several PW types into a single document rather than a document per PW type?
Or am I completely missing the point? Thanks Ben
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