Subject: Re: [Pce] Auto-bandwidth capability?

From: Dhruv Dhody <[email-masked]>
Date: Fri, 4 Mar 2016 04:53:35 +0000

Hi Robert,

We have updated the draft and added a section for Capability Advertisement.

https://tools.ietf.org/html/draft-dhody-pce-stateful-pce-auto-bandwidth-07#section-5.1

5.1.  Capability Advertisement

   During PCEP Initialization Phase, PCEP Speakers (PCE or PCC)
   advertise their support of Automatic Bandwidth Adjustment.  A PCEP
   Speaker includes the "Auto-Bandwidth Capability" TLV, in the OPEN
   Object to advertise its support for PCEP Auto-Bandwidth extensions.
   The presence of the "Auto-Bandwidth Capability" TLV in the OPEN
   Object indicates that the Automatic Bandwidth Adjustment is supported
   as described in this document.

   The PCEP protocol extensions for Auto-Bandwidth adjustments MUST NOT
   be used if one or both PCEP Speakers have not included the "Auto-
   Bandwidth Capability" TLV in their respective OPEN message.  If the
   PCEP speaker that supports the extensions of this draft but did not
   advertise this capability, then upon receipt of AUTO-BANDWIDTH-
   ATTRIBUTE TLV in LSPA object, it SHOULD generate a PCErr with error-
   type 19 (Invalid Operation), error-value TBD4 (Auto-Bandwidth
   capability was not advertised) and it will terminate the PCEP
   session.

5.1.1 AUTO-BANDWIDTH-CAPABILITY TLV

   The AUTO-BANDWIDTH-CAPABILITY TLV is an optional TLV for use in the
   OPEN Object for Automatic Bandwidth Adjustment via PCEP capability
   advertisement.  Its format is shown in the following figure:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               Type=[TBD5]     |            Length=4           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             Flags                           |B|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                    AUTO-BANDWIDTH-CAPABILITY TLV format

   The type of the TLV is [TBD5] and it has a fixed length of 4 octets.

   The value comprises a single field - Flags (32 bits):

   o  B (bandwidth usage - 1 bit): if set to 1 by a PCC, the B Flag
      indicates that the PCC allows reporting of bandwidth usage
      information; if set to 1 by a PCE, the B Flag indicates that the
      PCE is capable of receiving bandwidth usage information from the
      PCC.  The BANDWIDTH-USAGE-ATTRIBUTE TLV MUST be encoded when both
      PCEP speakers have the B Flag set.

   Unassigned bits are considered reserved.  They MUST be set to 0 on
   transmission and MUST be ignored on receipt.

   Advertisement of the Auto-Bandwidth capability TLV implies support of
   auto-bandwidth adjustment, as well as the objects, TLVs and
   procedures defined in this document.

Thanks for your comments!

Regards,
Dhruv

---------------------------------------------
From: Robert Varga <[email-masked]<mailto:[email-masked]>>
Date: Sun, Jan 10, 2016 at 10:20 PM
Subject: Auto-bandwidth capability?
To: [email-masked]<mailto:[email-masked]>

Hello,

looking over draft-dhody-pce-stateful-pce-auto-bandwidth, it seems to modify the base protocol, but this modification is not negotiated -- potentially leading to PCC/PCE protocol mismatch, leading to unexpected PCErr's when operations are attempted.

Would you consider adding a capability negotiation section, please?

Thanks,
Robert
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