Re: [Pals] [Detnet] A question about draft-gandhi-mpls-stamp-pw

Rakesh Gandhi <> Fri, 03 November 2023 12:24 UTC

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From: Rakesh Gandhi <>
Date: Fri, 03 Nov 2023 08:24:32 -0400
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To: Stewart Bryant <>
Cc: Greg Mirsky <>,,,,
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Subject: Re: [Pals] [Detnet] A question about draft-gandhi-mpls-stamp-pw
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Hi Greg, Stewart,

There are two use-cases that can benefit with STAMP packet without using
IP/UDP header and using STAMP GACH type:

*Use Case 1: *
•Same MPLS Encapsulation as Data Traffic carrying Control-Word (CW) for
monitoring ECMP and fate sharing
1.MPLS Ethernet PW [RFC4448]
2.L2-Specific Sublayer (L2SS) used in L2TPv3 PW carry CW (no IP header)
3.PLE [draft-ietf-pals-ple] traffic over PSN (as VPWS) carry CW (no IP
4.TDM over IP [RFC5087] payload (structure-aware/structure-agnostic) carry
CW with or without IP header

*Use Case 2: *
•Demultiplex Control Channel (VCCV/OAM)
1.G-ACh types allow to demultiplex *VCCV Control Channel *for PWs [RFC7708]
and MPLS-TP PWs [RFC7189]
•For example, G-ACh types for BFD packets with or without IP/UDP headers
allow to demultiplex VCCV Control Channel [RFC5885]
2.G-ACh types allow to demultiplex *OAM Control Channel *for MPLS-TP LSPs
and PWs [RFC5960]

Hope this clarifies.


On Mon, Nov 8, 2021 at 4:05 AM Stewart Bryant <>

> I am inclined to wonder the same.
> If it is about not having an IP address to hand, I seem to recall that one
> mode of use over 0x21 was to use local host.
> Stewart
> Sent from my iPad
> On 7 Nov 2021, at 21:01, Greg Mirsky <> wrote:
> Dear Authors,
> I've read the draft and would appreciate your clarification to my question:
>    - What benefits do you see in defining two new ACH types for STAMP
>    protocol over a PW?
> I believe that there are no apparent advantages of using PW, i.e., without
> IP/UDP headers, encapsulation compared to using IP/UDP. The latter can be
> easily done using ACH types 0x0021 and 0x0057 for IPv4 and IPv6 address
> family respectively.
> What do you think?
> Regards,
> Greg
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