Re: [Bier] [IANA #1359191] expert review for draft-ietf-bier-tether

["Jeffrey (Zhaohui) Zhang" <[e-mail]>]

[- IANA]

Hi Chris,

The benefit of tethering is explained in Section 1. Specifically, in Figure 2:

                              ------ BFR2 ------- BFER2
                             /
      BFER1 ---  BFR1 ---- X ------- BFR3 ------- BFER3
                          / \  .........
                         /   \
                      BFRx    ------ BFRn ------- BFERn

W/o using tethering, BFR1 needs to tunnel multiple copies to BFR2/3/…/n individually, which may not be desired if the BFR1—X link is bandwidth-limited.
W/ BFRx being a helper tethered to X, BFR1 only tunnels one copy to BFRx. The link between BFRx and X could be a fat local pipe and it’s much better for BFRx to tunnel individual copies to BFR2/3/…/n.

BFRx is a normal router but it may not be in the normal path from BFR1 and BFR2/3/…/n so the tethering procedure is needed.
You can also view it as a form of TI-LFA: BFR1 tunnels packets to BFRx (as if X went down) that is not in the normal path who will then send to the final destinations.

Thanks.
Jeffrey

-----Original Message-----
From: BIER <[e-mail]> On Behalf Of Christian Hopps
Sent: Wednesday, March 6, 2024 5:33 AM
To: [e-mail]
Cc: [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail]
Subject: Re: [Bier] [IANA #1359191] expert review for draft-ietf-bier-tether

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Allocating the code-point should not destabilize IS-IS itself so it's OK as far as that goes.

As an aside though, given a light read-through the draft's technology seems pretty questionable to me. A lot of complexity has been built here to place a router outside of the normal routing process and I don't understand why. This "helper" *router* could just be a normal BIER router in the domain and none of any of this would seem to be needed then.

Thanks,
Chris.



"David Dong via RT" <[e-mail]<mailto:[e-mail]>> writes:

> Dear Chris Hopps and Les Ginsberg (cc: bier WG),
>
> As the designated experts for the Sub-sub-TLVs for BIER Info Sub-TLV
> registry, can you review the proposed registration in draft-ietf-bier-tether-05 for us?
> Hannes has already approved this registration. Please see:
>
> https://datatracker.ietf.org/doc/draft-ietf-bier-tether/
>
> The due date assigned was March 1st.
>
> If this is OK, when the IESG approves the document for publication, we'll make the registration at:
>
> https://www.iana.org/assignments/isis-tlv-codepoints/
>
> We will act after all the experts have approved this registration, unless you tell us otherwise.
>
> With thanks,
>
> David Dong
> IANA Services Sr. Specialist
>
> On Mon Feb 26 18:43:14 2024, david.dong wrote:
>> Dear Chris Hopps and Les Ginsberg (cc: bier WG),
>>
>> As the designated experts for the Sub-sub-TLVs for BIER Info Sub-TLV
>> registry, can you review the proposed registration in
>> draft-ietf-bier-
>> tether-05 for us? Hannes has already approved this registration.
>> Please see:
>>
>> https://datatracker.ietf.org/doc/draft-ietf-bier-tether/
>>
>> The due date is March 1st.
>>
>> If this is OK, when the IESG approves the document for publication,
>> we'll make the registration at:
>>
>> https://www.iana.org/assignments/isis-tlv-codepoints/
>>
>> We will act after all the experts have approved this registration,
>> unless you tell us otherwise.
>>
>> With thanks,
>>
>> David Dong
>> IANA Services Sr. Specialist
>>
>> On Sun Feb 18 11:10:34 2024, [e-mail]<mailto:[e-mail]> wrote:
>> > Hi David,
>> >
>> > No concerns from my side to make the allocation.
>> >
>> > thanks,
>> >
>> > /hannes
>> >
>> > On Fri, Feb 16, 2024 at 10:26 PM David Dong via RT <
>> > [e-mail]<mailto:[e-mail]>> wrote:
>> >
>> > > Dear Chris Hopps, Hannes Gredler, Les Ginsberg (cc: bier WG),
>> > >
>> > > As the designated experts for the Sub-sub-TLVs for BIER Info Sub-
>> > > TLV registry, can you review the proposed registration in
>> > > draft-ietf-bier-tether-05 for us? Please see
>> > >
>> > > https://datatracker.ietf.org/doc/draft-ietf-bier-tether/
>> > >
>> > > The due date is March 1st.
>> > >
>> > > If this is OK, when the IESG approves the document for
>> > > publication, we'll make the registration at:
>> > >
>> > > https://www.iana.org/assignments/isis-tlv-codepoints/
>> > >
>> > > We will act after all the experts have approved this
>> > > registration, unless you tell us otherwise.
>> > >
>> > > With thanks,
>> > >
>> > > David Dong
>> > > IANA Services Sr. Specialist
>> > >
>> >




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