Mailing List Archive: nsp: ipv6

ToS-like processing of the IPv6 Traffic Class?

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fernando at gont

Sep 22, 2010, 1:49 AM

Post #1 of 7 (1553 views)
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ToS-like processing of the IPv6 Traffic Class?

Hi, folks,

I'm told that many deployments of IPv6 use the RFC 791 ToS (Type of
Service) semantics/definitions for the IPv6 Traffic Class field, e.g.
allowing strict precedence queuing.

Can anybody confirm this?

If this is the case, does this thing have to be explicitly enabled, or
is it the "default" behavior in some implementations?

Thanks!

Kind regards,
--
Fernando Gont
e-mail: fernando [at] gont || fgont [at] acm
PGP Fingerprint: 7809 84F5 322E 45C7 F1C9 3945 96EE A9EF D076 FFF1

brian.e.carpenter at gmail

Sep 22, 2010, 5:01 PM

Post #2 of 7 (1499 views)
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Re: ToS-like processing of the IPv6 Traffic Class? [In reply to]

Fernando,

I can't comment on what people do in practice, but RFC 2474
(which grandfathers IP Precedence from RFC 791) applies in
strictly the same way to IPv4 and IPv6.

Whether a particular network domain chooses to deploy diffserv
or not is an entirely local operational decision. I would
personally advocate deploying diffserv identically for IPv4
and IPv6, simply to minimise surprises, if products allow it.

Brian

On 2010-09-22 20:49, Fernando Gont wrote:
> Hi, folks,
>
> I'm told that many deployments of IPv6 use the RFC 791 ToS (Type of
> Service) semantics/definitions for the IPv6 Traffic Class field, e.g.
> allowing strict precedence queuing.
>
> Can anybody confirm this?
>
> If this is the case, does this thing have to be explicitly enabled, or
> is it the "default" behavior in some implementations?
>
> Thanks!
>
> Kind regards,

ek at google

Sep 23, 2010, 1:40 AM

Post #3 of 7 (1501 views)
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Re: ToS-like processing of the IPv6 Traffic Class? [In reply to]

> Whether a particular network domain chooses to deploy diffserv
> or not is an entirely local operational decision. I would
> personally advocate deploying diffserv identically for IPv4
> and IPv6, simply to minimise surprises, if products allow it.

Agreed. Cross-protocol uniformity generally lowers operational
overhead. (At the very least it reduces cognitive overload.)

merike at aristanetworks

Sep 23, 2010, 2:39 AM

Post #4 of 7 (1474 views)
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Re: ToS-like processing of the IPv6 Traffic Class? [In reply to]

Here's two pointers that may help:

http://www.juniper.net/techpubs/en_US/junos9.4/topics/concept/cos-ipv6-protocols-overview-solution.html

http://www.cisco.com/en/US/docs/ios/ipv6/configuration/guide/ip6-qos.html [especially the troubleshooting part]

It's been a few years since I dealt with configuring and knowing how to deal with buffers and queueing but I think you did have to specify explicitly how you'd want the queueing to be handled - there wasn't just a default 'allow strict precedence queueing'.

And while I'd agree that using same policies and configurations for IPv4/IPv6 will reduce operational headaches and confusion, I'd be curious to know if some people out there ARE using different QoS configurations for application traffic going over v4 vs v6 and why.

- merike

On Sep 22, 2010, at 1:49 AM, Fernando Gont wrote:

> Hi, folks,
>
> I'm told that many deployments of IPv6 use the RFC 791 ToS (Type of
> Service) semantics/definitions for the IPv6 Traffic Class field, e.g.
> allowing strict precedence queuing.
>
> Can anybody confirm this?
>
> If this is the case, does this thing have to be explicitly enabled, or
> is it the "default" behavior in some implementations?
>
> Thanks!
>
> Kind regards,
> --
> Fernando Gont
> e-mail: fernando [at] gont || fgont [at] acm
> PGP Fingerprint: 7809 84F5 322E 45C7 F1C9 3945 96EE A9EF D076 FFF1
>
>
>
>

fernando at gont

Sep 27, 2010, 1:10 AM

Post #5 of 7 (1470 views)
Permalink

Re: ToS-like processing of the IPv6 Traffic Class? [In reply to]

Hi, Merike,

Please find my comments inline...

> Here's two pointers that may help:
>
> http://www.juniper.net/techpubs/en_US/junos9.4/topics/concept/cos-ipv6-protocols-overview-solution.html
>
> http://www.cisco.com/en/US/docs/ios/ipv6/configuration/guide/ip6-qos.html
> [especially the troubleshooting part]

These two pointers are about diffserv (which is *not* what I was looking
for). I was asking about processing the IPv6 Traffic Class as in the
original IPv4 ToS definition (e.g., strict precedence-ordered queuing,
based on the Precedence field of the ToS, etc.)

Thanks!

Kind regards,
--
Fernando Gont
e-mail: fernando [at] gont || fgont [at] acm
PGP Fingerprint: 7809 84F5 322E 45C7 F1C9 3945 96EE A9EF D076 FFF1

merike at doubleshotsecurity

Sep 27, 2010, 8:40 AM

Post #6 of 7 (1460 views)
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Re: ToS-like processing of the IPv6 Traffic Class? [In reply to]

Hi..

Sorry for misunderstanding. I haven't seen any replies yet regarding how it is actually implemented in devices. Have you received any offline replies?

- merike

On Sep 27, 2010, at 1:10 AM, Fernando Gont wrote:

> Hi, Merike,
>
> Please find my comments inline...
>
>> Here's two pointers that may help:
>>
>> http://www.juniper.net/techpubs/en_US/junos9.4/topics/concept/cos-ipv6-protocols-overview-solution.html
>>
>> http://www.cisco.com/en/US/docs/ios/ipv6/configuration/guide/ip6-qos.html
>> [especially the troubleshooting part]
>
> These two pointers are about diffserv (which is *not* what I was looking
> for). I was asking about processing the IPv6 Traffic Class as in the
> original IPv4 ToS definition (e.g., strict precedence-ordered queuing,
> based on the Precedence field of the ToS, etc.)
>
> Thanks!
>
> Kind regards,
> --
> Fernando Gont
> e-mail: fernando [at] gont || fgont [at] acm
> PGP Fingerprint: 7809 84F5 322E 45C7 F1C9 3945 96EE A9EF D076 FFF1
>
>
>
>

brian.e.carpenter at gmail

Sep 27, 2010, 1:10 PM

Post #7 of 7 (1473 views)
Permalink

Re: ToS-like processing of the IPv6 Traffic Class? [In reply to]

On 2010-09-27 21:10, Fernando Gont wrote:
> Hi, Merike,
>
> Please find my comments inline...
>
>> Here's two pointers that may help:
>>
>> http://www.juniper.net/techpubs/en_US/junos9.4/topics/concept/cos-ipv6-protocols-overview-solution.html
>>
>> http://www.cisco.com/en/US/docs/ios/ipv6/configuration/guide/ip6-qos.html
>> [especially the troubleshooting part]
>
> These two pointers are about diffserv (which is *not* what I was looking
> for). I was asking about processing the IPv6 Traffic Class as in the
> original IPv4 ToS definition (e.g., strict precedence-ordered queuing,
> based on the Precedence field of the ToS, etc.)

The Cisco stuff makes it clear (as I said earlier) that precedence
is a subset of diffserv. If someone claims to support diffserv then they
are automatically claiming to support IP precedence. The juniper doc cited
doesn't appear to mention precedence, but the 3rd table at
http://www.juniper.net/techpubs/software/junos/junos80/swconfig80-cos/html/cos-ba-classifiers3.html
make it clear that they do support IP precedence as part of diffserv.
Which is exactly what RFC 2474 requires.

Brian

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