RE: Proposed response to the Liaison Statement on ASON Routing

["Wijnen, Bert (Bert)" <bwijnen@lucent.com>]

Thnaks for the proposed response.

It would be good if people could tell us if they agree or disagree
and if they disagree, then pls explain why.

If the response is acceptable, then it sounds to me that at least
there would be no impact on the draft-ietf-ccamp-lmp-08.txt
document, which is currently in IETF Last Call. Since we had split
the SONET/SDH material off into a separate document, my initial
evaluation made me think that the draft-ietf-ccamp-lmp-08.txt
would not have any ITU-T/T1X1 issues/concerns. The liason statement
did refer to it a few times and so I started to worry, but from
the (proposed) response it seems there is no isseu.

Would be good to get at least confimration of that by the end 
of the Last Call, and that is April 24th.

Thanks,
Bert 

> -----Original Message-----
> From: Jonathan Lang [mailto:Jonathan.Lang@RinconNetworks.com]
> Sent: vrijdag 18 april 2003 22:25
> To: ccamp@ops.ietf.org
> Cc: Kireeti@juniper.net; 'Ron Bonica (E-mail)'; zinin@psg.com;
> bwijnen@lucent.com; Dimitri.Papadimitriou@alcatel.be
> Subject: FW: Proposed response to the Liaison Statement on 
> ASON Routing
> 
> 
> All,
> 
> Here's a proposed response to the Liaison Statement from T1-X1 on LMP
> Link Verification, posted April 11, 2003.
> 
> Thanks,
> Jonathan & Dimitri
> --------------------------------------------------------------------
> Dear Mr. Biholar,
>  
>  
> >Context of Application Space
> <snip>
> >It is currently our understanding that the use case
> >scenario for which this procedure is applied encompasses 
> >both transport plane connectivity verification as well as 
> >correlation of these entities with the control plane.
> >ITU-T G.7714.1 is focused on discovering the transport 
> >plane link connection end point relationships and 
> >verifying their connectivity.
> >This Recommendation defines two procedures for performing
> >the connectivity verification function, one of which
> >utilizes either the Jx or the DCC bytes of the server
> >signal (termed "in-service"). The other approach in
> >G.7714.1, termed as "out of service", corresponds to
> >inserting a test signal in the payload of the server
> >signal. Based on an analysis of the data link state
> >definitions in draft-ietf-ccamp-lmp-08.txt, we understand
> >that the approach defined in the LMP test for physical 
> >connectivity occurs in the context of the "out of service"
> >state (as described in G.7714.1).
> >
> >Please confirm this.
> Yes, this is correct
> 
> >Usage of Jx Bytes
> >
> >In defining the Jx bytes within G.7714.1, the following
> >was taken into account: 
> >1. One consideration involved the case where the Discovery
> >Agent is located in an external system, and an external
> >interface is used by the Network Element to provision and
> >receive the Trail Trace message. As an existing text-
> >oriented Man-Machine Language, such as TL1, may be reused
> >to provide this interface, it was decided that the
> >discovery message be limited to printable characters.
> >Specifically, the TTI characters should be limited to
> >printable characters as per T.50 with trailing NULLs or 
> >SPACEs. Use of arbitrary bit patterns in the lower 7 bits
> >of each byte could prematurely terminate the pattern or
> >trigger fault notification for certain hardware or
> >software implementations. The strategy chosen in G.7714.1
> >avoids the danger by limiting the information content of
> >each byte to 6 bits (84 bits total) and uses a base 64
> >coding according to RFC2045 to place the information in
> >the available bits.
> We understand that a general transport plane discovery agent 
> application
> such as G.7714.1 may want to limit the format to printable characters.
> However, LMP is a subset of the GMPLS control plane where no such
> constraint exists.  As such, we don't think LMP link 
> verification needs
> to be constrained to be printable characters.
> 
> >2. Another consideration involved providing a means for
> >distinguishing this use of the Jx bytes from the
> >traditional use for Trail Trace identifiers in new
> >equipments. As a result, G.7714.1 includes a
> >distinguishing character ("+") as the first non-CRC byte
> >that will never appear as the first character of a TTI.
> >This requires modification of the trail termination
> >functions to prevent the raising of TTI mismatch
> >alarms during the connectivity verification process.
> We understand the need for this distinguishing character for 
> the G7714.1
> in-service application; however, LMP link verification is 
> designed to be
> used before a link is put in service.  It is our 
> understanding per G.806
> section 6.1, when a TTP is not in service, it is in the NMON 
> state (not
> monitored)."
>  
> >While the context for testing the transport plane
> >connectivity is different between the two documents, they
> >both use the Jx bytes of the server signal, and we invite
> >the IETF to determine the appropriateness of the above
> >aspects in their test signal definitions.
> We agree the context is different.  We evaluated the above aspects and
> we don't feel they are appropriate for LMP (see comments above).
> 
> >Even if these considerations are not relevant to this
> >context, it will be necessary to augment G.783 equipment
> >functions to recognize this new usage of Jx messages.
> We would be happy to provide assistance to T1X1/ITU-T in augmenting
> G.783 equipment functions to recognize the additional capability for
> GMPLS networking elements.
>  
> >Required Updates to SDH Equipment Specifications 
> >
> >SDH equipment specifications as they currently exist reflect
> >the usage of the Jx bytes prior to the development of
> >G.7714.1. ITU-T Study Group 15 has as a work item to
> >revise these equipment functions to include support for
> >these new functions. Specifically, this will involve
> >updates to trail termination functions to generate and
> >receive the new messages and to avoid unnecessary alarms in
> >the case where the new messages are received. In addition,
> >non-intrusive monitoring functions will need to be revised
> >so that unnecessary alarms are not raised when the
> >messages are observed en-route. Whether or not there is
> >further alignment between the message formats used in
> >G.7714.1 and the subject draft, the new functions to
> >support the subject draft will also need to be reflected
> >in the atomic functions in G.783. The sending and
> >receiving of these messages can be reflected in the trail
> >termination functions in a similar way to what we plan to
> >do for support of G.7714.1 functions.
> We understand that G7714.1 is addressing an in-service test procedure
> and needs to be concerned with NIM (and non-support of 
> G7714.1 by legacy
> NIM).  The LMP test procedure is a pre-service application.  
> We will be
> happy to work with T1X1/ITU SG15 to augment G.783 to recognize the
> additional capability for GMPLS networking elements.
> 
> >Terminology Differences
> <snip>
> >Based upon draft-ietf-ccamp-lmp-08.txt, Section 11.3.1,
> >the "up/free (in-service)" data link state appears to
> >correspond with what G.7714.1 refers to as "out-of-
> >service".  This difference in terminology has resulted in
> >different interpretations of the context.  Explaining the
> >scenarios further in the lmp test document would be
> >beneficial in establishing a translation between the
> >differing uses of the same terms.  Within ITU-T, work is
> >being initiated of draft Rec. G.fame, Framework for ASON
> >Management, where control plane/management plane
> >interactions will be addressed.
> We agree that terminology differences between IETF and ITU wrt GMPLS
> have been confusing.  There is an ongoing effort within CCAMP to work
> together with ITU/T1X1 on bridging the terminology gaps. For example,
> there is a new Internet draft
> (draft-aboulmagd-ccamp-transport-lmp-00.txt) being considered in CCAMP
> to do this mapping for LMP.
> 
> >Further Study Items 
> >
> >Following are some areas where further contributions are
> >requested:
> >1.	For SDH equipment functions in G.783, it needs to
> >be understood whether the application of the lmp test
> >message requires revision of NIM (non-intrusive
> >monitoring) functions. The reason for this is that the
> >test procedure is initiated between control entities at
> >the end-points of the trail, and intermediate points are
> >not necessarily aware that the test is taking place. For
> >G.7714.1, it was felt important for any termination or NIM
> >function to easily distinguish between the various uses of
> >the Jx bytes. It may be necessary for the subject draft
> >to use a similarly easily recognizable format. If no
> >revision to NIM functions is required for the context of
> >this draft, the architecture of the context for this
> >application (demonstrating why the NIM functions are not
> >required) should be reflected in G.803 and/or G.807/G.8080.
> We understand that G7714.1 is addressing an in-service test procedure
> and needs to be concerned with NIM (and non-support of 
> G7714.1 by legacy
> NIM).  The LMP test procedure is a pre-service application.  Can you
> clarify how "pre-service" applications impact 
> G.803/G.807/G.8080?  If we
> can provide assistance in updating these Recommendations to 
> reflect LMP
> applications, please let us know.
> 
> >2.Determination of whether it would be possible to use the
> >identical message formats in the subject draft as in
> >G.7714.1 for the connectivity verification function.
> We have evaluated the current formats in G.7714.1 and we believe are
> inappropriate for the usage of LMP.
>  
> >3.Determination of whether it would be possible to use the
> >same overall structure (distinguishing character, 4 bit
> >message type, 80 bit message body) if a different message
> >format or information content is required.
> As mentioned above, we believe the overall message structure and
> constraints
> are inappropriate for LMP.
> 
> >4.Work is needed to clarify under what
> >configurations/states (for example: no VC-n signals
> >carrying client traffic) the lmp test message is
> >applicable over J0.  If the signal can be framed and J0
> >can be recovered, the Regenerator Section is considered
> >as "in service" from a transport plane perspective. So
> >unlike the J1/J2 case, the application of the lmp test
> >message at the Regenerator Section does not occur in an
> >"out of service" state (from a transport plane
> >perspective).
> Section 6.1 of G.806 refers to a "termination function part 
> of a trail,
> which is in the process of set-up" as in the NMON state.  LMP link
> verification is based on pre-service testing.  Please let us 
> know if we
> can be of any assistance in updating the appropriate 
> Recommendations to
> support the GMPLS network element LMP capability.
> 
> >5. Clarification of the usage of transport and control
> >names for transport resources in the subject draft, as
> >described in G.8080 Amendment
> LMP defines a TRACE object when a separation between data and control
> plane name space is requested.
>  
> >6. Consideration of the ANSI 64-byte J1.
> This was mistakenly deleted from the latest version of the draft. This
> will be included in the next version.
> 
>