Hi Pablo,
Why does the hash needs to be based on the outer IPv6 header?
I understand there are some cases using outer IPv6 header (especially
Flow Label) will be suitable.
But I was not sure why we want to specifically limit the hash fields to
outer IPv6 in the draft, since there might be some cases you want to
use inner IPv4 header fields.
For example, one might want to use DX4 for IPv4 over SRv6 tunnel which
IPv6 SA/DA would be same for all packets and thus inner IPv4 header
might have more entropy.
Also, some hardware (ASIC/FPGA) implementation might want to chose using
inner IPv4 to reduce memory consumption by not keeping the already poped
outer IPv6 header fields or the hash calculated from it.
--
Kentaro Ebisawa <[email protected]>
------ Original Message ------
From: "Pablo Camarillo (pcamaril)" <[email protected]>
To: "[email protected]" <[email protected]>; "[email protected]"
<[email protected]>
Sent: 2019/03/06 18:20:59
Subject: Re: [spring] Flow Label in End.DX4
(draft-filsfils-spring-srv6-network-programming-07
Hi Kentaro,
The pseudocode is correct. The hash is based on the outer IPv6 header
(SA, DA, and Flow Label) before popping it.
Thanks,
Pablo.
From: spring <[email protected]> on behalf of Kentaro Ebisawa
<[email protected]>
Reply-To: Kentaro Ebisawa <[email protected]>
Date: Thursday, 21 February 2019 at 05:32
To: "[email protected]" <[email protected]>
Subject: [spring] Flow Label in End.DX4
(draft-filsfils-spring-srv6-network-programming-07
Hi
In 4.9 End.DX4 (draft-filsfils-spring-srv6-network-programming-07), I
noticed it requires Flow Label to be included in the hash in "after"
poping IPv6 header.
> 3. ELSE IF ENH = 4 ;; Ref2
> 4. pop the (outer) IPv6 header and its extension headers
> 5. forward to layer-3 adjacency bound to the SID S ;; Ref3
...
> Ref3: Selected based on a hash of the packet’s header (at least SA,
DA, Flow Label)
Since IPv6 packet is already poped, I think it might not be
appropriate to mandate use of Flow Label in this case but using
"identification field" for DX4. (unlike DX6)
Is this intentional or just a typo when copying from DX6?
Thanks,
--
Kentaro Ebisawa <[email protected]>
_______________________________________________
spring mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/spring
