Re: [v6ops] [Last-Call] Tsvart last call review of draft-ietf-v6ops-ipv6-ehs-packet-drops-05

Brian E Carpenter <brian.e.carpenter@gmail.com> Fri, 19 February 2021 20:14 UTC

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To: Fernando Gont <fgont@si6networks.com>, Gorry Fairhurst <gorry@erg.abdn.ac.uk>, tsv-art@ietf.org
Cc: last-call@ietf.org, draft-ietf-v6ops-ipv6-ehs-packet-drops.all@ietf.org, v6ops@ietf.org
References: <161366727749.10107.14514005068158901089@ietfa.amsl.com> <42668fb5-a355-e656-7d99-c40b3d33fb92@si6networks.com> <0e377231-c319-2157-30a0-759e2f96a692@gmail.com> <5f464f17-85ed-f105-35f9-02f35d04aed2@si6networks.com>
From: Brian E Carpenter <brian.e.carpenter@gmail.com>
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Date: Sat, 20 Feb 2021 09:14:08 +1300
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Subject: Re: [v6ops] [Last-Call] Tsvart last call review of draft-ietf-v6ops-ipv6-ehs-packet-drops-05
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Hi Fernando,

I slightly prefer this alternative:

> or add this:
> 
>    [RFC7098] discusses how the IPv6 FLow Label can used to enhance layer
>     3/4 (L3/4) load distribution and balancing for large server farms.
> 
> right after:
>     Thus, ECMP and Hash-based Load-
>     Sharing should be possible without the need to process the entire
>     IPv6 header chain to obtain upper-layer information to identify
>     flows.

Thanks,
    Brian

On 19-Feb-21 09:04, Fernando Gont wrote:
> Hi, Brian,
> 
> On 18/2/21 16:35, Brian E Carpenter wrote:
>> On 19-Feb-21 06:56, Fernando Gont wrote:
> [....]
>>>> * The ID also discusses use of the IPv6  Flow Label: This seems a little off
>>>> topic, but seems linked to EH implications on ECMP.  However, the final
>>>> sentence of this section is a reference to [Jaeggli-2018] which in turn
>>>> concludes that the IPv6 Flow Label should not be used it as a part of hashes
>>>> for load balancing. Yet, as far as I know, this is not the recommendation of
>>>> the IETF in 2020.
>>>
>>> FWIW, we discuss the Flow Label a bit because the usual reaction would
>>> be "why do you process the header chain for load-balancing, instead of
>>> employing the Flow Label?"
>>
>> However, Gorry is right that citing Joel's operational comments is only part
>> of the story. I immodestly suggest citing RFC 7098 too, for a discussion
>> of how the flow label can in principle be used for server load balancing.
> 
> Good grief! I thought we were referencing this one already (but looks 
> like we're not) Any suggestion on how to reference it?
> 
> E.g., we could do:
> 
>     Thus, ECMP and Hash-based Load-Sharing [rfc6434] [RFC7098] should be 
> possible
>     without the need to process the entire IPv6 header chain to obtain
>     upper-layer information to identify lows.
> 
> 
> plus adding it ALONG WITH RFC6438 here:
> 
>     making Flow Label-based ECMP
>     and Hash-based Load-Sharing [RFC6438] feasible.
> 
> 
> 
> xor add this:
> 
>    [RFC7098] discusses how the IPv6 FLow Label can used to enhance layer
>     3/4 (L3/4) load distribution and balancing for large server farms.
> 
> right after:
>     Thus, ECMP and Hash-based Load-
>     Sharing should be possible without the need to process the entire
>     IPv6 header chain to obtain upper-layer information to identify
>     flows.
> 
> 
> 
> Alternatively, if you can think of a better way to do it, please do let 
> us know.
> 
> Thanks!
> 
> Regards,
>