ben,
the discussion with dave has been reproduced in accelerated on the mailing list - for me it appears that the more "philosophical" conclusion can be positioned by answering to the following question "Was SONET/SDH or lambda switching initially intended to be controlled by GMPLS ?" if the response is "No, but nothing prevents to do so" the next question is what does prevent from applying GMPLS to other technologies knowing a substantial gain is obtained from its application - in certain conditions - (see motivations as part of this introduction for instance) ? key issue being which are these (technical) conditions and are there conditions that would preclude progressing this document - the response is simply the negative - there are no such conditions in the point-to-point - non-bridging - context where this document applies.
now, not sure there is a technical "firm" conclusion but the point on the ethernet label encoding appears as follows since so far there is potential interest to keep the label for ethernet generic enough and deduce its interpretation from type of link over which the label is used and intepreet its value according to the traffic_parameters and propose associations to cover cases such as case 2 of Appendix A of <draft-pwe3-ethernet-encap-08.txt> mechanisms that is also applicable to other tunneling technology since this mechanism is orthogonal to the use of PW's if required (example being Ethernet over SDH/OTH, for instance); however, if these are the only associations we see relevant as part of this document then we would fall back on the existing encoding with potential enhancement if so required -
to come to the point of the articulation the - generic - response holds in one line: it articulates GMPLS signaling for L2SC LSPs (note: the latter has been introduced in RFC 3945, RFC 3471, RFC 3473) - the motivations are detailed as part of the introduction of this document - i can not comment more from your initial statement since not detailed enough for me to be more specific
the response to the last question is relatively simple since the above mentioned do not include any specifics concerning ATM or FR - this document intends to close this gap by defining specific Traffic_Parameters for these technologies - is there an interest for doing so: response is yes otherwise the document would not have included the corr. details
voila, thanks,
- dimitri.
"Mack-Crane, T. Benjamin" <Ben.Mack-Crane@tellabs.com>
Sent by: owner-ccamp@ops.ietf.org
02/03/2005 12:16 CST
To: <dpapadimitriou@psg.com>, Dimitri PAPADIMITRIOU/BE/ALCATEL@ALCATEL, "David Allan" <dallan@nortelnetworks.com>
cc: "Adrian Farrel" <adrian@olddog.co.uk>, "Shahram Davari" <Shahram_Davari@pmc-sierra.com>, <ccamp@ops.ietf.org>
bcc:
Subject: RE: Layer 2 Switching Caps LSPsDimitri,
Can the off-line discussion be summarized for the benefit of those on
the list who did not participate? For me, the draft (and the current
discussion on the list) have not clearly articulated the problem being
addressed. If a summary of the conclusions of the off-line discussion
will do this, it would be useful.
I am also interested to know what is lacking in the current GMPLS RFCs
with respect to ATM and Frame Relay support that necessitates including
them in this new draft (presumably this is a part of the problem to be
solved).
Regards,
Ben
> -----Original Message-----
> From: owner-ccamp@ops.ietf.org [mailto:owner-ccamp@ops.ietf.org] On
Behalf
> Of dimitri papadimitriou
> Sent: Thursday, January 27, 2005 6:35 PM
> To: David Allan
> Cc: 'Adrian Farrel'; 'Shahram Davari'; ccamp@ops.ietf.org
> Subject: Re: Layer 2 Switching Caps LSPs
>
> dave - there was a lengthy off-line discussion suggested by the chairs
> intended to explain you the scope of the draft and its relatioship
with
> the ethernet data plane (after the question you raised during the f2f
> meeting) - this has been done and we have explained (via a lengthy
> exchange of e-mails) that this document and so the use of gmpls to
> control ethernet frame flows, is not targeting control of bridged
> ethernet environments - if this is not clear from the current document
> introduction we would have also to work on this part of the document -
> therefore, the below reference to MSTP is not in the current scope; on
> the other side, the use of the term "VLAN label" has created some
> confusion; therefore, in a next release i will simply refer to a
"label"
> of 32 bits (unstructured) because the intention was (and still is) to
> find an easy way to map the control of the ethernet frame flows on
each
> device they traverses without making any assumption on how this flow
is
> processed inside each node at the data plane level (note: on label
> values, RFC 3946 took an equivalent approach - for circuits - where
> sonet/sdh multiplexing structures have been used to create unique
> multiplex entry names i.e. labels - this concept is here applied for
> "virtual" circuits), so, if the working group is willing to enter into
a
> data plane oriented discussion to clarify the behaviour(s) onto which
> the present approach would be potentially applicable this is fine with
> me as long as we are within the scope of the initial motivations
>
> thanks,
> - dimitri.
>
> David Allan wrote:
> > Hi Adrian:
> >
> > Your suggestion is in a way reasonable but with the caveat that in
IEEE
> > terms, a bridging topology is currently all VLANs (802.1Q single
> spanning
> > tree) or partitioned into specific ranges (I believe 64 in 802.1s
> although I
> > do not claim to be an expert).
> >
> > If the PEs were to implement a bridge function and we were using
GMPLS
> to
> > interconnect them, then the control plane should be identifying
either
> all
> > VLANs (single spanning tree, which I beleive the draft covers by
> referring
> > simply to Ethernet port) or a VLAN range to be associated with the
LSP
> > consistent with 802.1s if it is to operate to interconnect bridges
> defined
> > by the IEEE...
> >
> > I suspect assuming any other behavior (e.g. LSP for single VLAN tag)
> would
> > go outside the boundary of what is currently defined...so alignment
with
> > 802.1s IMO would be a minimum requirement if we are to consider
carrying
> > VLAN information in GMPLS signalling....
> >
> > cheers
> > Dave
> >
> > You wrote....
> >
> >>Hi,
> >>
> >>The authors of the draft might like to clarify for the list
> >>exactly what data plane operations they are suggesting. To me
> >>it seems possible that the draft is proposing VLAN ID
> >>*swapping*. But an alternative is that the VLAN ID is used as
> >>a label, but that the same label is used for the full length
> >>of the LSP.
> >>
> >>Adrian
> >
> >
> >
> > .
> >
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