Re: [mpls] "Traffic Management" (was Re: Poll on renaming of EXP field)

["Eric Gray" <[e-mail]>]

George,

	WRT the use of TM by ATM, it is (as I mentioned at the
MPLS meeting) less interesting that "TM" has previously had a 
different meaning relative to ATM, than it is that "CoS" 
currently has a different meaning relative to the potential
use of MPLS in support of MEF ethernet services.

--
Eric Gray
Principal Engineer
Ericsson  

> -----Original Message-----
> From: George Swallow [mailto:[e-mail]] 
> Sent: Tuesday, August 19, 2008 3:13 PM
> To: Eric Gray; Francois Le Faucheur IMAP
> Cc: [e-mail]
> Subject: Re: [mpls] "Traffic Management" (was Re: Poll on 
> renaming of EXP field)
> Importance: High
> 
> WG Chair hat on:
> 
> I think it is important to signal the change by changing the 
> name.  Just
> clarifying the meaning of Experimental may result in a 
> document that does
> not get read.  Further, there is no registry for the EXP bit 
> usage and that
> usage can vary between LSPs running within the same network.  
> So comparing
> this to anything that has a registry and a process of IETF 
> consensus does
> not apply well here.
> 
> I'm also believe that when this is published as an RFC it 
> will say that it
> updates the appropriate RFCs.  Loa, please correct me if I am wrong.
> 
> WG Chair hat off:
> 
> One of the problems here is that every term used in this 
> general space is
> already over-loaded.  Further the emphasis implied by a 
> particular term
> varies with context (and consequently with the reader's 
> background).  For
> instance the term Traffic Management has very strong 
> connotations for those
> involved in the ATM Forum.
> 
> My personal view is that the term CoS is good enough.  But I 
> do believe that
> type of service (ToS) would have been an improvement.  It's 
> not that I think
> "type" is a better term than "class", it is that this would 
> make it the same
> as the IPv4 header.  The ToS field in the IP header now 
> encompasses both the
> DS codepoint and the ECN codepoint.  These are precisely the 
> functions that
> we are now trying to squeeze into three bits of the MPLS 
> Label Stack Entry.
> 
> I would argue strongly for this change were it not that in 
> IPv6 the same
> function is carried in a field called Traffic Class.
> 
> So CoS takes a little from each of v4 and v6.  Good enough.
> 
> ...George
> 
> 
> On 8/19/08 1:53 PM, "Eric Gray" <[e-mail]> wrote:
> 
> > Francois,
> > 
> > If I didn't care about the potential for extra work (and
> > possibly confusion as well), I would think "Traffic Management"
> > a better (because more generic) field name than "CoS" - but it
> > is still a change that may have far reaching consequences, and
> > which is better handled by a better explanation of the meaning
> > of the field than by any effort to come up with a better name
> > for it.
> > 
> > However, even the field-name "Traffic Management" may
> > not be generic enough.
> > 
> > At present, we seem to be agreed that currently defined
> > legitimate uses for the field are all related (at least in a
> > stretch) to something to do with how frames are expected to be
> > handled in forwarding.  But - given a precedent established in
> > RFC 3270 (which, among other things, emphasizes that meaning or
> > semantics of the field depends on a common understanding of why
> > an LSP was established) - it is actually clear that the field
> > might mean other things as well.  For example, the field might
> > - in some future context - be used to indicate error handling
> > for packets that will be dropped, or macro statistics buckets
> > that individual packets belong to (unrelated to other handling
> > of a packet so marked).
> > 
> > In fact, we're re-hashing many of the same arguments that
> > led to the field's being named as it was.
> > 
> > So, the issue is all about what constitutes a "legitimate
> > use" - which I would argue is defined by IETF consensus, and is
> > an issue better handled by good explanation than by renaming.
> > 
> > --
> > Eric Gray
> > Principal Engineer
> > Ericsson  
> > 
> >> -----Original Message-----
> >> From: [e-mail] [mailto:[e-mail]] On
> >> Behalf Of Francois Le Faucheur IMAP
> >> Sent: Tuesday, August 19, 2008 12:42 PM
> >> To: George Swallow
> >> Cc: [e-mail]; Francois Le Faucheur IMAP
> >> Subject: [mpls] "Traffic Management" (was Re: Poll on
> >> renaming of EXP field)
> >> 
> >> Hi,
> >> 
> >> Someone earlier suggested "Traffic Management". While it can most
> >> certainly be argued this would not be a perfect name either
> >> (or other  
> >> names would be closer to "perfection"), is there a good
> >> argument I am  
> >> missing for why "COS" is obviously better (or more "good enough")
> >> than "Traffic Management"? (considering we want to capture both
> >> Diffserv and ECN/PCN use of EXP field)
> >> 
> >> Thanks
> >> 
> >> Francois
> >> 
> >> 
> >> On 18 Aug 2008, at 22:23, George Swallow wrote:
> >> 
> >>> During the last call on "EXP field" renamed to  "CoS Field"
> >>> draft-ietf-mpls-cosfield-def-04.txt, there were comments on
> >>> alternatives to the name COS.
> >>> 
> >>> This message initiates a two week poll on whether the name COS
> >>> is good enough, or if some other name is needed.  The poll closes
> >>> 23:59 Sept 1 GMT.
> >>> 
> >>> Please answer with a simple yes or no.  You may send any
> >> additional  
> >>> comment
> >>> in a separate message (with a different subject line).
> >>> 
> >>> ...George
> >>> 
> >>> _______________________________________________
> >>> mpls mailing list
> >>> [e-mail]
> >>> https://www.ietf.org/mailman/listinfo/mpls
> >> 
> >> _______________________________________________
> >> mpls mailing list
> >> [e-mail]
> >> https://www.ietf.org/mailman/listinfo/mpls
> >> 
> 
> 
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