Hi Les,

Please see inline, 

> -----Message d'origine-----
> De : Les Ginsberg (ginsberg) [mailto:[EMAIL PROTECTED] 
> Envoyé : lundi 5 mars 2007 23:12
> À : LE ROUX Jean-Louis RD-CORE-LAN; [EMAIL PROTECTED]; 
> [EMAIL PROTECTED]
> Cc : Mike Shand (mshand); David Ward; Chris Hopps
> Objet : RE: [Pce] Comments on 
> draft-ietf-pce-disco-proto-isis-02.txt from ISISWG
> 
> 
> Jean-Louis -
> 
> Sorry for the delayed response.
> Comments inline.
> 
> > -----Original Message-----
> > From: LE ROUX Jean-Louis RD-CORE-LAN 
> [mailto:[EMAIL PROTECTED] 
> > ftgroup.com]
> > Sent: Thursday, March 01, 2007 11:14 AM
> > To: [EMAIL PROTECTED]; [EMAIL PROTECTED]; Les Ginsberg (ginsberg)
> > Subject: RE: [Pce] Comments on 
> draft-ietf-pce-disco-proto-isis-02.txt 
> > from ISISWG
> > 
> > Hi Les,
> > 
> > Thanks for these comments.
> > 
> > Please see inline,
> > 
> > > -----Message d'origine-----
> > > De : Adrian Farrel [mailto:[EMAIL PROTECTED] Envoyé : 
> mercredi 21 
> > > février 2007 11:53 À : [EMAIL PROTECTED] Objet : [Pce] Comments on 
> > > draft-ietf-pce-disco-proto-isis-02.txt from ISISWG
> > >
> > > ----- Original Message -----
> > >
> > > From: "Les Ginsberg (ginsberg)" <[EMAIL PROTECTED]>
> > > To: "Adrian Farrel" <[EMAIL PROTECTED]>; <[email protected]>
> > > Cc: "Jean Philippe Vasseur (jvasseur)" <[EMAIL PROTECTED]>
> > > Sent: Monday, February 19, 2007 6:56 PM
> > > Subject: RE: [Isis-wg] PCE working group last call
> > >
> > > ondraft-ietf-pce-disco-proto-isis-02.txt
> > >
> > >
> > > Section 1
> > >
> > >       ABR: IGP Area Border Router (L1L2 router).
> > >
> > > LES: Use "L2 capable router" instead - or eliminate the 
> definition 
> > > since as Mike points out it is not used in the document.
> > 
> > OK, to be eliminated
> > 
> > >
> > >       Examples of domains include IGP areas and 
> Autonomous Systems.
> > >
> > > LES: area and domain are not the same - though a domain may have 
> > > only one area. I would omit this sentence.
> > 
> > In the PCE context the defintion of a domain is as follows 
> (as per RFC
> > 4655):
> > 
> > "A domain is any collection of network elements within a 
> common sphere 
> > of address management or path computation responsibility.  
> Examples of 
> > domains include IGP areas, Autonomous Systems (ASes), and multiple 
> > ASes within a Service Provider network.  Domains of path 
> computation 
> > responsibility may also exist as sub-domains of areas or ASes."
> > 
> > Is that OK if we refer to [RFC4655] and indicate that this 
> definition 
> > applies to a PCE context?
> 
> I think in an IS-IS specific document this is going to get 
> confusing - as area and domain have a very specific meaning. 
> So I think you need to define this as "PCE-domain", reference 
> RFC4655, and make clear that this should be distinguished 
> from a domain as defined by ISO 10589 - and use "PCE_domain" 
> in all the appriopriate places in the document.

what about the term "Path Computation Domain"?

> 
> > 
> > 
> > >
> > > Section 3.1.1
> > >
> > >      inter-area, inter-AS, inter-layer\205
> > >
> > > LES: Remove Formatting character \205
> > 
> > OK
> > 
> > >
> > > Section 3.2
> > >
> > >    The flooding scope for PCE information advertised 
> through IS-IS can
> > >    be limited to one or more IS-IS areas the PCE belongs 
> to, or can 
> > > be
> > >
> > > LES: Flooding can only be area or domain scoped flooding.
> > > There is no defined method to restrict flooding to some subset of 
> > > the areas in a domain.
> > 
> > Right. We are going to rephrase as follows:
> > 
> > The flooding scope for PCE information advertised through 
> IS-IS can be 
> > a single L1 area, a L1 area and the L2 sub-domain (when the 
> PCE is a 
> > L1L2 node), or the entire IS-IS domain (S bit set in the Router 
> > Capability TLV).
> 
> The three options are:
> 
> 1)Single L1 area (only available at Level-1 - S bit clear)
> 2)L2 sub-domain (only available at Level-2 when S bit is 
> clear) 3)Entire routing domain (S bit set)
> 
> You cannot do a combination of #1 and #2 as your statement suggests.

Actually a L1L2 node may include a PCED TLV in a Router Cap TLV with the S bit 
cleared, both in its L1 and L2 LSPs. We are going to clarify this point.


> 
> > 
> > Does that make sense?
> > 
> > >
> > >    extended across the entire IS-IS routing domain.
> > >    Note that some PCEs may belong to multiple areas, in 
> which case the
> > >    flooding scope may comprise these areas. This could be 
> the case 
> > > for a
> > >
> > >    L1L2 router for instance advertising its PCE 
> information within the
> > >    L2 area and/or a subset of its attached L1 area(s).
> > >
> > > LES: There is no such thing as an L2 area. There is the L2 
> > > sub-domain, which consists of all L2 routers in a domain.
> > 
> > OK, we are going to remove the above paragraph
> > 
> > >
> > > Section 4.1. The IS-IS PCED TLV
> > >
> > > LES: This is a sub-TLV. As Mike has pointed out, it is 
> important to 
> > > use that terminology consistently throughout the document.
> > 
> > OK
> > 
> > >
> > >    The format of the IS-IS PCED TLV and its sub-TLVs is the 
> > > identical to
> > >
> > >
> > > LES: s/the identical/identical
> > 
> > OK
> > 
> > >
> > > At the end of Section 4.1 it might be helpful to add:
> > >
> > > "The following sub-sections describe the sub-TLVs which may be 
> > > carried within the PCED sub-TLV."
> > 
> > OK
> > 
> > >
> > > Section 4.1.3
> > >
> > >    Two DOMAIN sub-TLVs are defined
> > >
> > >             Sub-TLV type   Length        Name
> > >                  1         Variable     Area ID sub-TLV
> > >                  2           4          AS number sub-TLV
> > >
> > > LES: These codepoints are not mentioned in the IANA section.
> > 
> > OK, to be added.
> > 
> > >
> > > Section 4.1.3.1
> > >
> > >    VALUE: This comprises a variable length IS-IS area ID. This is 
> > > the
> > >
> > >           combination of an Initial Domain Part (IDP) and 
> High Order
> > >           part of the Domain Specific part (HO-DSP)
> > >
> > > LES: Rather than invent a term (HO-DSP) which ISO 10589 does not 
> > > use, say "this is the area address as defined in [ISO]".
> > 
> > OK
> > 
> > > Which causes me to mention that you have no reference to ISO
> > > 10589 in the references section, a most serious breach of 
> etiquette 
> > > indeed!!
> > 
> > OK, to be added
> > 
> > >
> > > Section 4.1.4
> > >
> > > LES: The domain/area sub-TLVs (nested level 3) which are 
> defined in
> > > 4.1.3 appear to be "reused" here. This should be 
> explicitly stated 
> > > as the scope of the sub-TLV codepoint for domain/area sub-TLVs is 
> > > the parent sub-TLV (PCE-domain or
> > > PCE-NEIG-DOMAIN) and therefore the codepoints cannot be 
> assumed to 
> > > be the same - it MUST be explicitly stated.
> > 
> > OK
> > 
> > >
> > > Section 5
> > >
> > >    defined in [IS-IS-CAP]. A such, elements of procedures are 
> > > inherited
> > >
> > >
> > > LES: s/A such/As such
> > 
> > OK
> > 
> > >
> > >    domain, itMUST be carried within an IS-IS CAPABILITY 
> TLV having 
> > > the S
> > >
> > >
> > > LES: s/itMUST/it MUST
> > 
> > OK
> > 
> > >
> > >    A PCE MUST originate a new IS-IS LSP whenever the content
> > >
> > > LES: There is a generic issue here. As a PCE is not a 
> router running 
> > > the IS-IS protocol, it cannot generate any LSPs. :-) 
> Therefore you 
> > > cannot say (as you do in multiple places) "a PCE originates a new 
> > > IS-IS LSP".
> > 
> > You are right the PCE is a functional block. But it is often 
> > assimilated to the node hosting the PCE function, which is an IS-IS 
> > node in this draft.
> > Is that OK if we say "An IS-IS node acting as PCE MUST originate"...
> 
> But it is also possible to have a PCE which is NOT running on 
> a node which is acting as an IS-IS router. In that case the 
> PCE information is passed to the IS-IS node in some manner 
> which is beyond the scope of this document and IS-IS still 
> advertises the information, but as the IP address of the PCE 
> is NOT an address of the IS-IS router it is wrong to say the 
> IS-IS is "acting as a PCE". IS-IS is simply advertising PCE 
> information which has been provided to it. It does not act as 
> a PCE in any way.

OK, I see, so what about "An IS-IS router MUST originate a new IS-IS LSP 
whenever the content of any of the PCED TLV changes"?




> 
> > 
> > > Similarly, you say:
> > >
> > >    A PCC MUST be
> > >    able to detect that the PCED TLV has been removed from 
> an IS-IS 
> > > LSP.
> > >
> > > As a PCC is also not equivalent to a router running the IS-IS 
> > > protocol, perhaps you want to say "A PCC MUST be informed..."
> > 
> > Let say "An IS-IS node acting as PCC..." ?
> 
> Please see my previous comment.

What about "An IS-IS router MUST be able to detect..."?


> 
> > 
> > > - although I tend to think that all of the communication 
> between the 
> > > applications (PCE and
> > > PCC) and the IS-IS protocol instance is out of scope for this 
> > > document.
> > 
> > Yes it is out of the scope.
> 
> So, you could just remove the language entirely.

Would it be OK if we only refer to "IS-IS routers"?

Best Regards,

JL


> 
>    Les
> 
> > 
> > 
> > 
> > >
> > >    The PCE address, i.e. the address indicated within the 
> PCE ADDRESS
> > >    sub-TLV, MUST be distributed as part of IS-IS routing;
> > >
> > > LES: I am not sure what you mean here. Do you mean that 
> there MUST 
> > > be a host route advertisement for the PCE address(es)?
> > > Or do you simply mean that the PCE address(es) must be 
> reachable via 
> > > some prefix(es) advertised by IS-IS? If the latter, then please 
> > > change the wording. As written it suggests there is a special 
> > > advertisement required.
> > 
> > Yes this is the latter, we are going to rephrase as suggested.
> > 
> > >
> > >  Section 8
> > >
> > >   IS-IS provides no mechanism for protecting the privacy of LSAs, 
> > > and
> > >
> > > LES: I don't know what you are trying to say here. Do you 
> mean TLVs?
> > > Certainly not LSAs!
> > 
> > Yes TLVs :-)
> > 
> > >
> > >
> > >    in particular the privacy PCE discovery information.
> > >
> > > LES: s/privacy/privacy of
> > 
> > OK
> > 
> > Again, thanks a lot for these comments.
> > Once the last call is completed, we are going to submit a 
> new revision 
> > that accounts for all these comments.
> > 
> > Best Regards,
> > 
> > JL
> > 
> > >
> > >    Les
> > >
> > >
> > > > -----Original Message-----
> > > > From: Adrian Farrel [mailto:[EMAIL PROTECTED]
> > > > Sent: Wednesday, February 14, 2007 9:36 AM
> > > > To: [email protected]
> > > > Cc: Jean Philippe Vasseur (jvasseur)
> > > > Subject: [Isis-wg] PCE working group last call
> > > ondraft-ietf-pce-disco-
> > > > proto-isis-02.txt
> > > >
> > > > Hi,
> > > >
> > > > The PCE working group is holding a last call on
> > > >
> > > http://www.ietf.org/internet-drafts/draft-ietf-pce-disco-proto
> > > -isis-02.t
> > > xt
> > > >
> > > > Since this I-D proposes protocol extensions to ISIS we
> > > would like the
> > > ISIS
> > > > working group to participate in this last call, and we have
> > > accordingly
> > > > made
> > > > the last call period three weeks in order to give you plenty of 
> > > > time
> > > to
> > > > respond.
> > > >
> > > > The last call will end at 12 noon GMT on Thursday 8th March.
> > > >
> > > > Please send your comments to the PCE mailing list if you are
> > > subscribed.
> > > > Otherwise, please channel your comments through the PCE
> > > working group
> > > > chairs ([EMAIL PROTECTED] and [EMAIL PROTECTED])
> > > >
> > > > Background reading is:
> > > > RFC4655 - The PCE Architecture
> > > > RFC4674 - Requirements for Path Computation Element 
> (PCE) Discovery
> > > >                   (These are the requirements that this I-D is
> > > addressing)
> > > >
> > > >
> > > > Thanks,
> > > > Adrian
> > > >
> > > >
> > > >
> > > > _______________________________________________
> > > > Isis-wg mailing list
> > > > [email protected]
> > > > https://www1.ietf.org/mailman/listinfo/isis-wg
> > >
> > >
> > >
> > >
> > >
> > > _______________________________________________
> > > Pce mailing list
> > > [email protected]
> > > https://www1.ietf.org/mailman/listinfo/pce
> > >
> > >
> > >
> 

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