[c-nsp] QoS and Router Originated Traffic

[Ivan]

Hi,

I have had a lot of similar feedback. I have found

* Changing the IP precedence via ""ip local policy route-map" doesn't
directly set the COS - the locally generated traffic doesn't have a 802.1q
header to contain the 802.1p bits.  Depending on the platform (and
probably other stuff) the IP precedence value may or may not end copied
into the 802.1p field when the exiting interface has 802.1q tagged
packets.

*Testing on ASR1K and 800 Series ISRs I have found that they don't copy
the IP precedence into the 802.1p field.  A 7600 with ES+ does.

*IPv6 NS and ND packets are marked with IP precedence 7.  On the 7600 the
"ip local policy route-map" doesn't work for these packets - it does work
for other IPv6 packets .

*The "ip local policy route-map" solution impacts RP traffic going out all
interfaces.  I only require a specific interface to have traffic marked in
a certain way.

*I would prefer to only modify the 802.1p bits while leaving the IP
precedence.

At this stage I am thinking the only way to achieve what I am looking for
is to set only the 802.1p bits using an additional device...

Ivan

> Hi,
>
> We use "ip local policy route-map xyz" to apply a route-map to traffic
> that is originated locally on the router. The route-map is like any normal
> one with a match statement (using ACL), then a set statement.
>
>
> regards,
> Tony.
>
>
>
>>________________________________
>> From: Anton Kapela <tkapela at gmail.com>
>>To: Ivan <cisco-nsp at itpro.co.nz>
>>Cc: cisco-nsp <cisco-nsp at puck.nether.net>
>>Sent: Tuesday, 25 September 2012 10:07 PM
>>Subject: Re: [c-nsp] QoS and Router Originated Traffic
>>
>>Kind of out-dated, but useful reading:
>>
>>http://www.cisco.com/en/US/tech/tk543/tk544/technologies_tech_note09186a0080094612.shtml
>>
>>-Tk
>>
>>On Sep 17, 2012, at 5:21 AM, Ivan <cisco-nsp at itpro.co.nz> wrote:
>>
>>> Hi,
>>>
>>> I have a requirement to ensure all traffic across certain links have
>>> particular CoS markings.  Applying QoS polices on the links works but
>>> doesn't capture router originated traffic - BGP, ARP, IPv6 ND etc.
>>>
>>> As a potential solution I have tested using IPv4 and IPv6 PBR to force
>>> router traffic via lo0
>>>
>>> route-map LP permit 10
>>> set interface Loopback0
>>>
>>> ip local policy route-map LP
>>> ipv6 local policy route-map LP
>>>
>>> and have set a QoS policy on lo0
>>>
>>> interface Loopback0
>>> service-policy input LOOP0-IN
>>>
>>> this sets a qos-group which is matched the outgoing non-loopback
>>> interface and sets CoS as required.
>>>
>>> As far as I can tell it works pretty well but I have a few questions
>>>
>>> 1) I don't think this works for ARP.  I tried to match protocol arp
>>> using the loopback0 policy but
>>>
>>> router(config-if)#service-policy input LOOP0-IN
>>> 'match protocol arp' is not supported on input service-policy
>>>
>>> is there anyway to set the CoS value for ARP traffic from the router,
>>> ideally only on some interfaces?
>>>
>>> 2) Is this configuration going to kill my router - maybe I am forcing
>>> some process switching?
>>>
>>> Thanks
>>>
>>> Ivan
>>