Re: [Pce] PCEP support for S-BFD configuration for PCE initiated LSPs

[Dhruv Dhody <[e-mail]>]

Hi Marina / Orly,

There was a draft a while back which did propose passing BFD parameters -
https://datatracker.ietf.org/doc/html/draft-li-pce-bfd-00.
Looking at the minutes -
https://www.ietf.org/proceedings/95/minutes/minutes-95-pce it also had some
support from the WG.

I have included the authors in cc, if they and others in the WG would like
to revive this work.

Now, coming to use of association object -- the use of association is
useful when we there is a clear relationshep between a set of the LSPs.
In this case, I assume the only relationship is that they share the same
BFD parameters.
I would suggest thinking through if association is the best technique or a
new TLV under LSPA a better technique.
Also checkout IOAM draft
https://datatracker.ietf.org/doc/draft-ietf-pce-pcep-ifit/ which uses the
latter and I would think keeping this consistent would be a good idea.

Thanks!
Dhruv



On Wed, Aug 24, 2022 at 8:03 PM Marina Fizgeer <[e-mail]>
wrote:

> Hi, Dhruv and all,
>
> My colleagues and I are working on PCEP PCE initiated and PCC initiated
> LSP with S-BFD configuration (the same may be relevant for BFD as well).
>
> As far as we understand, it is currently not possible to configure S-BFD
> parameters via PCEP (like other future MPLS parameters).
>
> We propose to add a new association type to allow additional LSP
> configuration (as example and the first using, S-BFD parameters).
>
> New association type shall be part of negotiation process in session
> establishment (that both PCEP speakers support this type).
>
> In TLV:
> [image:
> https://ilptlppjir01.ecitele.com:7443/confluence/download/attachments/144821588/image2021-12-7_10-29-57.png?version=1&modificationDate=1660463565000&api=v2]
>
> Both NPT and NC MUST support ASSOC-Type-List TLV
>
> *PCEP Speaker* shall use* ASSOC-Type-List TLV *to report its support in *Assoc-Type
> = MPLS-Additional-Params  (65535)*
>
> *PCEP Speaker* shall send the S-BFD Association Object and the new TLVs
> only if it has received from its peer (in the ASSOC-Type-List TLV) the
> *MPLS-Additional-Params *Association Type in the Open message
>
>
>
> Support new proprietary TLVs
>
> PCEP speaker shall implement new TLVs to report the S-BFD Initiator
> attributes configured per SR-TE LSP (SR policy) according to the table
> below. This table is part of our implementation as example:
>
>
>
> *Attribute*
>
> *Range*
>
> *Default*
>
> *Type*
>
> *Data Type*
>
> *Description/Limitations*
>
> *S-BFD enable*
>
> True/False
>
> False
>
> R/W
>
> Boolean
>
> Specify if S-BFD is enable on this tunnel. Means enable on all LSPs
>
> *Remote Discriminator*
>
> 1 - 4294967295
>
> IP address of the Destination of the tunnel
>
> R/W
>
> Uint32
>
> Specify the remote discriminator of the session
>
> *Minimal TX interval*
>
> As for regular BCM based MH-BFD
>
> <20|50|100|1000|10000>
>
> 100
>
> R/W
>
> Uint32
>
> Specify the Minimal Transmit Interval (mSec)
>
> *Multiplier*
>
> 2-255
>
> 3
>
> R/W
>
> Uint8
>
> Specify the Multiplier value.
>
>
>
> *Support "S-BFD Enable" TLV *
>
> The "S-BFD Enable" TLV will be sent for the S-BFD ASSOCIATION object  only
> if the user (PCEP speaker) configured S-BFD for the specified LSP (for
> failure detection purpose)
>
> [image:
> https://ilptlppjir01.ecitele.com:7443/confluence/download/attachments/144821588/image2022-8-14_19-42-18.png?version=1&modificationDate=1660495338000&api=v2]
>
> *Type: 65503*
>
> *Length:* 4
>
> *B: *Enable/Disable S-BFD for this association group. If B=1 then S-BFD
> will be enabled. If B=0 then S-BFD will be disabled
>
>
>
>
>
> *Support "BFD Parameters" TLV *
>
> This new TLV is optional, and will be sent for the S-BFD ASSOCIATION
> object only if the user (PCEP speaker) modified the defaults of the S-BFD
> parameters for a specified tunnel.
>
> [image:
> https://ilptlppjir01.ecitele.com:7443/confluence/download/attachments/144821588/image2022-8-10_11-38-56.png?version=1&modificationDate=1660120736000&api=v2]
>
> *Type: 65502*
>
> *Length:* 6
>
> *Min Tx Interval:* 4 bytes - Specify the Minimal Transmit Interval (mSec)
>
> *Multiplier: *8 bits
>
>
>
> *Support "S-BFD Discriminator" TLV *
>
> The "S-BFD Discriminator" proprietary TLV is optional, and will be sent
> for S-BFD Association Group only if the user (CLI / NC)  wishes to change
> the Remote Discriminator of the SR Policy
>
> [image:
> https://ilptlppjir01.ecitele.com:7443/confluence/download/attachments/144821588/image2022-8-10_11-19-18.png?version=1&modificationDate=1660119559000&api=v2]
>
> *Type: 65501*
>
> *Length:* 4
>
> *Remote Discriminator:* NPTi will always use Router ID (IPv4 address of
> Router)
>
>
>
>
>
> Best regards,
>
> Marina and Orly
>
>
>
> Notice: This e-mail together with any attachments may contain information
> of Ribbon Communications Inc. and its Affiliates that is confidential
> and/or proprietary for the sole use of the intended recipient. Any review,
> disclosure, reliance or distribution by others or forwarding without
> express permission is strictly prohibited. If you are not the intended
> recipient, please notify the sender immediately and then delete all copies,
> including any attachments.
>