Path Computation Element Communication Protocol (PCEP) Extensions for Stateful PCE
draft-ietf-pce-stateful-pce-21

[Ballot comment]
In 10.1, some references seem to be needed to
say how to do that authentication and
encryption. IIUC, that's a work in progress,
or is that right? If so, when's it likely to
be done and usable?

[Ballot comment]
Below is Lionel's OPS DIR review.

I've pointed out some "issues" that might not be real issues for
people involved in PCE but that could be at least clarified for
readers of this document. Detailed comments are provided below.

Regards,

Lionel

********************
2.  Terminology

  This document uses the following terms defined in [RFC5440]: PCC,
  PCE, PCEP Peer, PCEP Speaker.

  This document uses the following terms defined in [RFC4655]: TED.

  This document uses the following terms defined in [RFC3031]: LSP.

  This document uses the following terms defined in
  [I-D.ietf-pce-stateful-pce-app]: Stateful PCE, Passive Stateful
PCE,
  Active Stateful PCE, Delegation, LSP State Database.

[LM] I didn't find a clear definition of the LSP state, except through
the definition of the LSP State database in ietf-pce-stateful-pce-app,
i.e.

  The second is the LSP
  State Database (LSP-DB), in which a PCE stores attributes of all
  active LSPs in the network, such as their paths through the
network,
  bandwidth/resource usage, switching types and LSP constraints.

As this document heavily relies on this LSP state concept, it could be
useful to (re-)define it in this document or to find a
correct reference for it.


3.2.  Objectives

  The objectives for the protocol extensions to support stateful PCE
  described in this document are as follows:

[...]

  o  Allow a PCC to delegate control of its LSPs to an active
stateful
      PCE such that a given LSP is under the control of a single PCE
at
      any given time.  A PCC may revoke this delegation at any time
      during the lifetime of the LSP.  If LSP delegation is revoked
      while the PCEP session is up, the PCC MUST notify the PCE about
      the revocation.  A PCE may return an LSP delegation at any
point
      during the lifetime of the PCEP session.

[LM] I'm assuming that the PCE returning the delegation has also to
notify the PCC. If so, maybe:
   
    "the If LSP delegation is returned by the PCE while the PCEP
      session is up, the PCE MUST notify the PCE about the
revocation."

[LM] the bullet point could be then splitted into two bullets, one for
PCC, one for PCE.

5.4.  Capability Advertisement

  During PCEP Initialization Phase, PCEP Speakers (PCE or PCC)
  advertise their support of stateful PCEP extensions.  A PCEP
Speaker
  includes the "Stateful PCE Capability" TLV, described in
  Section 7.1.1, in the OPEN Object to advertise its support for
PCEP
  stateful extensions.  The Stateful Capability TLV includes the
'LSP
  Update' Flag that indicates whether the PCEP Speaker supports LSP
  parameter updates.

  The presence of the Stateful PCE Capability TLV in PCC's OPEN
Object
  indicates that the PCC is willing to send LSP State Reports
whenever
  LSP parameters or operational status changes.

  The presence of the Stateful PCE Capability TLV in PCE's OPEN
message
  indicates that the PCE is interested in receiving LSP State
Reports
  whenever LSP parameters or operational status changes.

[LM] is it "willing/interested for" or just a capability indication?
It is not the same thing from a procedure point of view.

  The PCEP extensions for stateful PCEs MUST NOT be used if one or
both
  PCEP Speakers have not included the Stateful PCE Capability TLV in
  their respective OPEN message.  If the PCEP Speaker on the PCC
  supports the extensions of this draft but did not advertise this
  capability, then upon receipt of PCUpd message from the PCE, it
MUST
  generate a PCErr with error-type 19 (Invalid Operation),
error-value
  2 (Attempted LSP Update Request if the stateful PCE capability was
  not advertised)(see Section 8.5) and it SHOULD terminate the PCEP
  session.  If the PCEP Speaker on the PCE supports the extensions
of
  this draft but did not advertise this capability, then upon
receipt
  of a PCRpt message from the PCC, it MUST generate a PCErr with
error-
  type 19 (Invalid Operation), error-value 5 (Attempted LSP State
  Report if active stateful PCE capability was not advertised) (see
  Section 8.5) and it SHOULD terminate the PCEP session.

[LM] why the recommendation for closing the session if an explicit
error is sent back? The session could remain open i.e. except stateful
PCEP extensions,everything else would be fine. If the session
termination is the right thing to do, as we are in a clear error case
(as the PCEP speaker should not send the report or the update), the
SHOULD should probably be a MUST hee.

[LM] Is there any reason to use a specific error in such a case? The
PCE could just behave as a PCE not supporting the feature. Why is it
important for the supporting PCEP speaker to make the difference? The
generic behavior described in RFC5440 is not enough?

[LM] active/passive mode are not  advertized in PCEP.
s/if active stateful PCE capability was not advertised/if stateful PCE
capability was not advertised

>From RFC5440: "6.9.  Reception of Unknown Messages

  A PCEP implementation that receives an unrecognized PCEP message
MUST
  send a PCErr message with Error-value=2 (capability not
supported).

  If a PCC/PCE receives unrecognized messages at a rate equal or
  greater than MAX-UNKNOWN-MESSAGES unknown message requests per
  minute, the PCC/PCE MUST send a PCEP CLOSE message with close
  value="Reception of an unacceptable number of unknown PCEP
message".
  A RECOMMENDED value for MAX-UNKNOWN-MESSAGES is 5.  The PCC/PCE
MUST
  close the TCP session and MUST NOT send any further PCEP messages
on
  the PCEP session."

[LM] If it is the case, the error handling would be the same between a
PCEP speaker supporting the feature but not advertizing it and a PCEP
speaker not supporting the feature. And it would not be possible
possible to use the specific error responses to infer the capability
supported by the other node.

  Note that even if the update
  capability has not been advertised, a PCE can still accept LSP
Status
  Reports from a PCC and build and maintain an up to date view of
the
  state of the PCC's LSPs.

[LM] I don't undersand. Is it not in contradiction with
 
  "If the PCEP Speaker on the PCE supports the extensions of
  this draft but did not advertise this capability, then upon
receipt
  of a PCRpt message from the PCC, it MUST generate a PCErr with
error-
  type 19 (Invalid Operation), error-value 5 (Attempted LSP State
  Report if active stateful PCE capability was not advertised) (see
  Section 8.5) and it SHOULD terminate the PCEP session."

Or does it mean that there is another way than PCRpt message for the
PCC to send LSP status reports to the PCE?

[LM] In this section, it is not described how non-supporting PCEP
speaker will hanlded the new TLV. It could be said that unrecognized
TLVs will be ignored (as per RFC5440) and OPEN messages will be
handled as per RFC5440 (if the comment above is accepted).

[LM] Would it be useful to discover (using another TLV) whether the
PCE is an active/passive stateful PCE, as in IGP-based capabilities
discovery mechanism?

5.5.  IGP Extensions for Stateful PCE Capabilities Advertisement

  When PCCs are LSRs participating in the IGP (OSPF or IS-IS), and
PCEs
  are either LSRs or servers also participating in the IGP, an
  effective mechanism for PCE discovery within an IGP routing domain
  consists of utilizing IGP advertisements. 

[...]

  Note that while active and passive stateful PCE capabilities may
be
  advertised during discovery, PCEP Speakers that wish to use
stateful
  PCEP MUST negotiate stateful PCEP capabilities during PCEP session
  setup, as specified in the current document.  A PCC MAY initiate
  stateful PCEP capability negotiation at PCEP session setup even if
it
  did not receive any IGP PCE capability advertisements.

[LM] As said above, an as stated in section 5.4:
  "The PCEP extensions for stateful PCEs MUST NOT be used if one or
both
  PCEP Speakers have not included the Stateful PCE Capability TLV in
  their respective OPEN message."

What is the real added-value of this IGP-based mechanism? Only to be
able to identify active PCE/passive PCE mode?

5.6.  State Synchronization

[LM] "State" could be misleading. "LSP State Sync" would be more
approriate/accurate I think.

  The purpose of State Synchronization is to provide a
checkpoint-in-
  time state replica of a PCC's LSP state in a PCE.  State
  Synchronization is performed immediately after the Initialization
  phase ([RFC5440]).

  During State Synchronization, a PCC first takes a snapshot of the
  state of its LSPs state, then sends the snapshot to a PCE in a
  sequence of LSP State Reports.  Each LSP State Report sent during
  State Synchronization has the SYNC Flag in the LSP Object set to
1.
  The set of LSPs for which state is synchronized with a PCE is
  determined by advertised stateful PCEP capabilities and PCC's
local
  configuration (see more details in Section 9.1).

[LM] It seems that :

  "The set of LSPs for which state is synchronized"

should be:

  "The set of LSPs for which state is to be synchronized"

[LM] I don't see how the "advertised stateful PCEP capabilities" have
an effect on the set of LSP to synchronize. The capabilities adv is
only used to discover stateful PCE capabilities and see if the related
PCEP extensions can be used. The identification of the LSPs to
synchronize seems to be only based on policies configured in the PCC.

  The end of synchronization marker is a PCRpt message with the SYNC
  Flag set to 0 for an LSP Object with PLSP-ID equal to the reserved
  value 0 (see Section 7.3).  In this case, the LSP Object SHOULD
NOT
  include the SYMBOLIC-PATH-NAME TLV and SHOULD include the LSP-
  IDENTIFIERS TLV with the special value of all zeroes.  The PCRpt
  message MUST include an empty ERO as its intended path and SHOULD
NOT
  include the optional RRO object for its actual path.

[LM] What is the reason for the use of "SHOULD" here, instead of
"MUST"?

  If the PCC has
  no state to synchronize, it SHOULD only send the end of
  synchronization marker.

[LM] Is it when there is no active LSP? If it is, it could be useful
to clarify it. And it is maybe not so related to the text just before.
It could be clarified in a separate paragraph.

  A PCE SHOULD NOT send PCUpd messages to a PCC before State
  Synchronization is complete.  A PCC SHOULD NOT send PCReq messages
to
  a PCE before State Synchronization is complete.  This is to allow
the
  PCE to get the best possible view of the network before it starts
  computing new paths.

[LM] it is obviously assumed that this requirement is true for PCC/PCE
explicitly advertizing support of stateful PCE capability.

  If the PCC encounters a problem which prevents it from completing
the
  state transfer, it MUST send a PCErr message with error-type 20
(LSP
  State Synchronization Error) and error-value 5 (indicating an
  internal PCC error) to the PCE and terminate the session.

[LM] s/state transfer/LSP state synchornization

5.7.1.  Delegating an LSP

  A PCC delegates an LSP to a PCE by setting the Delegate flag in
LSP
  State Report to 1.  If the PCE does not accept the LSP Delegation,
it
  MUST immediately respond with an empty LSP Update Request which
has
  the Delegate flag set to 0.  If the PCE accepts the LSP
Delegation,
  it MUST set the Delegate flag to 1 when it sends an LSP Update
  Request for the delegated LSP (note that this may occur at a later
  time).  The PCE MAY also immediately acknowledge a delegation by
  sending an empty LSP Update Request which has the Delegate flag
set
  to 1.

[LM] if the delegation is not aceepted by the PCE, I assume that the
PCC should not set the Delegate flag in subsequent LSP state report.
If it is, this could be clarified somewhere in this section.

[..]

  Note that for an LSP to remain delegated to a PCE, the PCC MUST
set
  the Delegate flag to 1 on each LSP Status Report sent to the PCE.

[LM] s/each LSP Status Report/each LSP State Report for this LSP.

5.7.2.1.  Explicit Revocation

  When a PCC decides that a PCE is no longer permitted to modify an
  LSP, it revokes that LSP's delegation to the PCE.  A PCC may
revoke
  an LSP delegation at any time during the LSP's life time.  A PCC
  revoking an LSP delegation MAY immediately clear the LSP state
  provided by the PCE, but to avoid traffic loss, it SHOULD do so in
a
  make-before-break fashion.

[LM] After PCE delegation revocation, is there really a requirement
for LSP state clean-up? The revocation is used to remove the
authorization of LSP state update to the PCE but I don't see why the
PCC would clear LSP state after revocation. The LSP state can be
updated using operator-defined default parameters, right?

  If the PCC has received but not yet acted
  on PCUpd messages from the PCE for the LSP whose delegation is
being
  revoked, then it SHOULD ignore these PCUpd messages when
processing
  the message queue.  All effects of all messages for which
processing
  started before the revocation took place MUST be allowed to
complete
  and the result MUST be given the same treatment as any LSP that
had
  been previously delegated to the PCE (e.g. the state MAY be
  immediately cleared). 

[LM] If I correctly understood the text above, after revocation of the
PCE delegation,
- any PCUpd should be rejected and not ignored
- the LSP state(s) that was delegated to the PCE cannot be changed
until all the messages in the message queue have been processed.

If I'm correct, the text above could be clarified. 

  Any further PCUpd messages from the PCE are
  handled according to the PCUpd procedures described in this
document.

[LM] Not understood. Further PCUpd "will result in the PCC sending a
PCErr message" as said after the figure.

5.7.2.2.  Revocation on Redelegation Timeout

  When a PCC's PCEP session with a PCE terminates unexpectedly, the
PCC
  MUST wait the time interval specified in Redelegation Timeout
  Interval before revoking LSP delegations to that PCE and
attempting
  to redelegate LSPs to an alternate PCE.  If a PCEP session with
the
  original PCE can be reestablished before the Redelegation Timeout
  Interval timer expires, LSP delegations to the PCE remain intact.

[LM] In case of PCEP session interruption, is there a requirement for
the PCE to update delegated LSP states in order to ensure the
synchronization between states in the PCE and in the PCC?

  Likewise, when a PCC's PCEP session with a PCE terminates
  unexpectedly, the PCC MUST wait for the State Timeout Interval
before
  flushing any LSP state associated with that PCE.

[LM] it should be clarified that the "flushing" applies only if there
is no other PCE. Otherwise, see section 5.7.4

  Note that the State
  Timeout Interval timer may expire before the PCC has redelegated
the
  LSPs to another PCE, for example if a PCC is not connected to any
  active stateful PCE or if no connected active stateful PCE accepts
  the delegation. 

[LM] Not sure to understand. Is it "if a PCC is not connected to any
OTHER active stateful PCE or if no OTHER connected active stateful PCE
accepts the delegation?

  In this case, the PCC MUST flush any LSP state set
  by the PCE upon expiration of the State Timeout Interval and
revert
  to operator-defined default parameters or behaviors.  This
operation
  SHOULD be done in a make-before-break fashion.

[LM] I think it is important to make the distinction between PCC with
only one PCE and PCC with N PCE. The "Note that" could be put in a
separate section.

  The State Timeout Interval MUST be greater than or equal to the
  Redelegation Timeout Interval and MAY be set to infinity (meaning
  that until the PCC specifically takes action to change the
parameters
  set by the PCE, they will remain intact).

[LM] reading "the State Timeout Interval timer may expire before the
PCC has redelegated the LSPs to another PCE" could be understood as
STI timer < RTI timer. And here, it is stated STI timer >= RTI timer.
Depending on the clarification on the previous comment, this text
could be also clarified (or not)

5.7.3.  Returning a Delegation

  In order to keep a delegation, a PCE MUST set the Delegate flag to
1
  on each LSP Update Request sent to the PCC.  A PCE that no longer
  wishes to update an LSP's parameters SHOULD return the LSP
delegation
  back to the PCC by sending an empty LSP Update Request which has
the
  Delegate flag set to 0.  If a PCC receives an LSP Update Request
with
  the Delegate flag set to 0 (whether the LSP Update Request is
empty
  or not), it MUST treat this as a delegation return.

                    +-+-+                    +-+-+
                    |PCC|                    |PCE|
                    +-+-+                    +-+-+
                      |                        |
                      |---PCRpt, Delegate=1--->| LSP delegated
                      |            .          |
                      |            .          |
                      |            .          |
                      |<--PCUpd, Delegate=0----| Delegation returned
                      |                        |
                      |---PCRpt, Delegate=0--->| No delegation for
LSP
                      |                        |

                    Figure 6: Returning a Delegation

  If a PCC cannot delegate an LSP to a PCE (for example, if a PCC is
  not connected to any active stateful PCE or if no connected active
  stateful PCE accepts the delegation), the LSP delegation on the
PCC
  will time out within a configurable Redelegation Timeout Interval
and
  the PCC MUST flush any LSP state set by a PCE at the expiration of
  the State Timeout Interval.

[LM] same comment: is it "for example, if a PCC is not connected to
any OTHER active stateful PCE or if no OTHER connected active stateful
PCE accepts the delegation"?

[LM] "the PCC MUST flush any LSP state set" should be completed by
"and revert to operator-defined default parameters or behaviors",
right?

5.7.5.  Redelegation on PCE Failure

[...]

  If the PCE crashes but recovers within the Redelegation Timeout,
both
  the delegation state and the LSP state are kept intact.

[LM] "Recover" here seems to be associated with the PCEP session (as
linked to the Redelegation Timeout), not with the LSP states
maintained by the PCE.

[LM] How can the PCC be ensured that the PCE has not been impacted by
the stop/restart and that LSP states are intact? Is there any need for
a sanity check?

  If the PCE crashes but does not recover within the Redelegation
  Timeout, the delegation state is returned to the PCC.  If the PCC
can
  redelegate the LSPs to another PCE, and that PCE accepts the
  delegations, there will be no change in LSP state.  If the PCC
cannot
  redelegate the LSPs to another PCE, then upon expiration of the
State
  Timeout Interval, the state set by the PCE is flushed, which may
  cause change in the LSP state.

[LM] the last sentence is difficult to understand. How to understand
"flush the state MAY cause change in the LSP state"? It would like
talking about two different states in the PCC.
[LM] about "flushed", should we add "and revert to operator-defined
default parameters or behaviors"?

[...]

  If there is a standby PCE, the Redelegation Timeout may be set to
0
  through policy on the PCC, causing the LSPs to be redelegated
  immediately to the PCC, which can delegate them immediately to the
  standby PCE.  Assuming the State Timeout Interval is greater than
the
  Redelegation Timeout, and assuming the standby PCE takes similar
  decisions as the failed PCE, the LSP state will be kept intact.

[LM] the first "assuming" is not an assumption but a requirement,
according to "The State Timeout Interval MUST be greater than or equal
to the Redelegation Timeout Interval"

5.8.1.  Passive Stateful PCE Path Computation Request/Response

                    +-+-+                    +-+-+
                    |PCC|                    |PCE|
                    +-+-+                    +-+-+
                      |                        |
  1) Path computation |----- PCReq message --->|
      request sent to  |                        |2) Path computation
      PCE              |                        |  request received,
                      |                        |  path computed
                      |                        |
                      |<---- PCRep message ----|3) Computed paths
                      |    (Positive reply)  |  sent to the PCC
                      |    (Negative reply)  |
  4) LSP Status change|                        |
      event            |                        |
                      |                        |
  5) LSP Status Report|----- PCRpt message --->|
      sent to all      |            .          |
      stateful PCEs    |            .          |
                      |            .          |
  6) Repeat for each  |----- PCRpt message --->|
      LSP status change|                        |
                      |                        |

    Figure 7: Passive Stateful PCE Path Computation Request/Response

[LM] in the figure, please use "state" instead of "status"


7.1.  OPEN Object

  This document defines one new optional TLVs for use in the OPEN
  Object.

s/one new optional TLVs/one new optional TLV

7.2.  SRP Object

  The SRP (Stateful PCE Request Parameters) object MUST be carried
  within PCUpd messages and MAY be carried within PCRpt and PCErr
  messages.  The SRP object is used to correlate between update
  requests sent by the PCE and the error reports and state reports
sent
  by the PCC.

[LM] Should we add the following text at the end of the section?

  "Optional TLVs may be included within the SRP object body. The
  specification of such TLVs is outside the scope of this document."

7.3.  LSP Object

[...]

  TLVs that may be included in the LSP Object are described in the
  following sections.

[LM] I think that it is possible to add extra optional TLV, not
defined in this document. This should be clarified if I'm correct.

[Ballot comment]
Minor comment:
The U flag in the STATEFUL-PCE-CAPABILITY TLV is probably not necessary as the presents of this TVL already indicates that updates are supported; however not an issue.

[Ballot comment]
1. Maybe it's just me, but what is the Symbolic Path Name used for?  There is a mapping to the PLSP-ID, and the required lifetime may be different, but I don't see where the use is explained (or why it's even needed).  Also, is there any expectation to the length or character set?  Given that the "symbolic path name MAY be specified by an operator in a PCC's configuration", I'm guessing it has to be something than can be printed...but there are no specifics.

2. In 9.2: "PCEP session configuration and information in the PCEP MIB module SHOULD be extended to include advertised stateful capabilities...".  Ok, but I think the "SHOULD" is out of place.  s/SHOULD/should

[Ballot comment]
1. Maybe it's just me, but what is the Symbolic Path Name used for?  There is a mapping to the PLSP-ID, and the required lifetime may be different, but I don't see where the use is explained (or why it's even needed).  Also, is there any expectation to the length or character set?  Given that the "symbolic path name MAY be specified by an operator in a PCC's configuration", I'm guessing it has to be something than can be printed...but there are no specifics.

2. In 9.2: "PCEP session configuration and information in the PCEP MIB module SHOULD be extended to include advertised stateful capabilities..."  Ok, but I think the "SHOULD" is out of place.  s/SHOULD/should

(Via drafts-lastcall@iana.org): IESG/Authors/WG Chairs:

The IANA Services Operator has completed its review of draft-ietf-pce-stateful-pce-18.txt. If any part of this review is inaccurate, please let us know.

The IANA Services Operator understands that, upon approval of [ RFC-to-be ], there are nine actions which we must complete.

First, in the Path Computation Element (PCE) Capability Flags subregistry in the Open Shortest Path First v2 (OSPFv2) registry located at:

https://www.iana.org/assignments/ospfv2-parameters/

the TEMPORARY registrations for bits 11 and 12 will be made permanent and the reference will be changed to [ RFC-to-be ].

Second, in the PCEP Messages subregistry in the Path Computation Element in the Protocol (PCEP) Numbers registry located at:

https://www.iana.org/assignments/pcep/

the TEMPORARY registrations for values 10 and 11 will be made permanent and the reference will be changed to [ RFC-to-be ].

Third, in the PCEP Objects subregistry also in the Path Computation Element Protocol (PCEP) Numbers registry located at:

https://www.iana.org/assignments/pcep/

the TEMPORARY registrations for Object-Class values 32 and 33 will be made permanent and the reference will be changed to [ RFC-to-be ].

Fourth, a new registry is to be created called the LSP Object Flag Field registry. The new registry will be a subregistry of the Path Computation Element Protocol (PCEP) Numbers registry located at:

https://www.iana.org/assignments/pcep/

The new registry will be managed via Standards Action as defined in RFC 5226. There are initial registrations in the new registry as follows:

Bit Description Reference
--------+---------------------+--------------
0-4 Reserved [ RFC-to-be ]
5-7 Operational (3 bits) [ RFC-to-be ]
8 Administrative [ RFC-to-be ]
9 Remove [ RFC-to-be ]
10 SYNC [ RFC-to-be ]
11 Delegate [ RFC-to-be ]

Fifth, in the PCEP-ERROR Object Error Types and Values subregistry of the Path Computation Element Protocol (PCEP) Numbers registry located at:

https://www.iana.org/assignments/pcep/

The following TEMPORARY Error-type/Error-value combinations will be made permanent and the reference will be changed to [ RFC-to-be ]:

Error type: 6; Error-value: 8
Error type: 6; Error-value: 9
Error type: 6; Error-value: 10
Error type: 6; Error-value: 11
Error type: 19; Error-value: 1
Error type: 19; Error-value: 2
Error type: 19; Error-value: 3
Error type: 19; Error-value: 5
Error type: 20; Error-value: 1
Error type: 20; Error-value: 5

Sixth, in the Notification Object subregistry also in the Path Computation Element Protocol (PCEP) Numbers registry located at:

https://www.iana.org/assignments/pcep/

The TEMPORARY registration for Notification-Type 4 and its associated Notification-values will be made permanent and the reference will be changed to [ RFC-to-be ].

Seventh, in the PCEP TLV Type Indicators subregistry also in the Path Computation Element Protocol (PCEP) Numbers registry located at:

https://www.iana.org/assignments/pcep/

the following TEMPORARY registrations will be made permanent and the references will be changed to [ RFC-to-be ]:

Values: 16, 17, 18, 19, 20 and 21.

Eighth, a new registry is to be created called the STATEFUL-PCE-CAPABILITY TLV Flag Field registry. The new registry will be a subregistry of the Path Computation Element Protocol (PCEP) Numbers registry located at:

https://www.iana.org/assignments/pcep/

The new registry will be managed via Standards Action as defined in RFC 5226. There are initial registrations in the new registry as follows:

Bit Description Reference
----+-------------------------------+--------------
31 LSP-UPDATE-CAPABILITY [ RFC-to-be ]

Ninth, a new registry is to be created called the LSP-ERROR-CODE TLV Error Code Field registry. The new registry will be a subregistry of the Path Computation Element Protocol (PCEP) Numbers registry located at:

https://www.iana.org/assignments/pcep/

The new registry will be managed via Standards Action as defined in RFC 5226. There are initial registrations in the new registry as follows:

Value Meaning Reference
-----------+--------------------------------------+--------------
1 Unknown reason [ RFC-to-be ]
2 Limit reached for PCE-controlled LSPs [ RFC-to-be ]
3 Too many pending LSP update requests [ RFC-to-be ]
4 Unacceptable parameters [ RFC-to-be ]
5 Internal error [ RFC-to-be ]
6 LSP administratively brought down [ RFC-to-be ]
7 LSP preempted [ RFC-to-be ]
8 RSVP signaling error [ RFC-to-be ]

The IANA Services Operator understands that these nine actions are the only ones required to be completed upon approval of [ RFC-to-be ].

Note:  The actions requested in this document will not be completed until the document has been approved for publication as an RFC. This message is only to confirm what actions will be performed.

Thank you,

Sabrina Tanamal
IANA Services Specialist
PTI

The following Last Call announcement was sent out:

From: The IESG
To: "IETF-Announce"
CC: db3546@att.com, "Julien Meuric" , pce@ietf.org, pce-chairs@ietf.org, draft-ietf-pce-stateful-pce@ietf.org, julien.meuric@orange.com
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (PCEP Extensions for Stateful PCE) to Proposed Standard


The IESG has received a request from the Path Computation Element WG
(pce) to consider the following document:
- 'PCEP Extensions for Stateful PCE'
  as Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits
final comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2017-02-28. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the
beginning of the Subject line to allow automated sorting.

Abstract


  The Path Computation Element Communication Protocol (PCEP) provides
  mechanisms for Path Computation Elements (PCEs) to perform path
  computations in response to Path Computation Clients (PCCs) requests.

  Although PCEP explicitly makes no assumptions regarding the
  information available to the PCE, it also makes no provisions for PCE
  control of timing and sequence of path computations within and across
  PCEP sessions.  This document describes a set of extensions to PCEP
  to enable stateful control of MPLS-TE and GMPLS LSPs via PCEP.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-pce-stateful-pce/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-pce-stateful-pce/ballot/

The following IPR Declarations may be related to this I-D:

  https://datatracker.ietf.org/ipr/2045/
  https://datatracker.ietf.org/ipr/2046/

As required by RFC 4858, this is the current template for the Document
Shepherd Write-Up.

Changes are expected over time. This version is dated 24 February 2012.

(1) What type of RFC is being requested (BCP, Proposed Standard,
Internet Standard, Informational, Experimental, or Historic)? 

Proposed Standard.

Why is this the proper type of RFC?

Defines protocol extensions.

Is this type of RFC indicated in the
title page header?

Yes.

(2) The IESG approval announcement includes a Document Announcement
Write-Up. Please provide such a Document Announcement Write-Up. Recent
examples can be found in the "Action" announcements for approved
documents. The approval announcement contains the following sections:

Technical Summary

  The Path Computation Element Communication Protocol (PCEP) provides
  mechanisms for Path Computation Elements (PCEs) to perform path
  computations in response to Path Computation Clients (PCCs) requests.

  Although PCEP explicitly makes no assumptions regarding the
  information available to the PCE, it also makes no provisions for PCE
  control of timing and sequence of path computations within and across
  PCEP sessions.  This document describes a set of extensions to PCEP
  to enable stateful control of MPLS-TE and GMPLS LSPs via PCEP.

Working Group Summary

The document already has a long history. It started with squatting some codepoints, which resulted in publishing RFC 7470, a.k.a. "RFC 7150 bis".
Some changes have been heavily argued, mainly because of some reluctance to update existing implementations, but this version reflects a WG consensus.

Document Quality

  Are there existing implementations of the protocol?

There are several implementations, including one open source (OpenDaylight).

Have a significant number of vendors indicated their plan to
  implement the specification?

Yes, even more than plans.

Are there any reviewers that
  merit special mention as having done a thorough review,
  e.g., one that resulted in important changes or a
  conclusion that the document had no substantive issues?

Some updates have been triggered by a couple of operators, thanks to some interoperability testing between several implementations.

If there was a MIB Doctor, Media Type or other expert review,
  what was its course (briefly)? In the case of a Media Type
  review, on what date was the request posted?

N/A

Personnel

  Who is the Document Shepherd?

Julien Meuric

Who is the Responsible Area Director?

Deborah Brungard

(3) Briefly describe the review of this document that was performed by
the Document Shepherd.  If this version of the document is not ready
for publication, please explain why the document is being forwarded to
the IESG.

The review triggered some updates and left time for interoperability feedback, resulting in some clarifications.

(4) Does the document Shepherd have any concerns about the depth or
breadth of the reviews that have been performed?

Only at first review, tied to early implementations; fixes have been incorporated since.

(5) Do portions of the document need review from a particular or from
broader perspective, e.g., security, operational complexity, AAA, DNS,
DHCP, XML, or internationalization? If so, describe the review that
took place.

Usual Routing Directorate's review is expected.

(6) Describe any specific concerns or issues that the Document Shepherd
has with this document that the Responsible Area Director and/or the
IESG should be aware of? For example, perhaps he or she is uncomfortable
with certain parts of the document, or has concerns whether there really
is a need for it. In any event, if the WG has discussed those issues and
has indicated that it still wishes to advance the document, detail those
concerns here.

A couple of protocol messages/objects include some redundancy inherited from early implementations. They have been discussed and the WG can live with them.

(7) Has each author confirmed that any and all appropriate IPR
disclosures required for full conformance with the provisions of BCP 78
and BCP 79 have already been filed. If not, explain why.

Yes.

(8) Has an IPR disclosure been filed that references this document?
If so, summarize any WG discussion and conclusion regarding the IPR
disclosures.

IPR disclosure exists. No public discussion has happened, but licensing terms are only defensive.

(9) How solid is the WG consensus behind this document? Does it
represent the strong concurrence of a few individuals, with others
being silent, or does the WG as a whole understand and agree with it? 

The document triggered various discussions and can be considered a consensus of the WG as a whole.

(10) Has anyone threatened an appeal or otherwise indicated extreme
discontent? If so, please summarise the areas of conflict in separate
email messages to the Responsible Area Director. (It should be in a
separate email because this questionnaire is publicly available.)

No threat, discussions remained reasonable.

(11) Identify any ID nits the Document Shepherd has found in this
document. (See https://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
thorough.

OK.

(12) Describe how the document meets any required formal review
criteria, such as the MIB Doctor, media type, and URI type reviews.

N/A.

(13) Have all references within this document been identified as
either normative or informative?

Yes.

(14) Are there normative references to documents that are not ready for
advancement or are otherwise in an unclear state? If such normative
references exist, what is the plan for their completion?

No.

(15) Are there downward normative references references (see RFC 3967)?
If so, list these downward references to support the Area Director in
the Last Call procedure.

No.

(16) Will publication of this document change the status of any
existing RFCs? Are those RFCs listed on the title page header, listed
in the abstract, and discussed in the introduction? If the RFCs are not
listed in the Abstract and Introduction, explain why, and point to the
part of the document where the relationship of this document to the
other RFCs is discussed. If this information is not in the document,
explain why the WG considers it unnecessary.

N/A.

(17) Describe the Document Shepherd's review of the IANA considerations
section, especially with regard to its consistency with the body of the
document. Confirm that all protocol extensions that the document makes
are associated with the appropriate reservations in IANA registries.
Confirm that any referenced IANA registries have been clearly
identified. Confirm that newly created IANA registries include a
detailed specification of the initial contents for the registry, that
allocations procedures for future registrations are defined, and a
reasonable name for the new registry has been suggested (see RFC 5226).

IANA section looks fine and has already been used to request early allocation.

(18) List any new IANA registries that require Expert Review for future
allocations. Provide any public guidance that the IESG would find
useful in selecting the IANA Experts for these new registries.

No identified expert review.

(19) Describe reviews and automated checks performed by the Document
Shepherd to validate sections of the document written in a formal
language, such as XML code, BNF rules, MIB definitions, etc.

None.