[c-nsp] Define MPLS default EXP value?

[Lauri Turunen]

On 30.7.2010 17:57, Patrick Abeldt wrote:
> Hi all,
>
> we're planning to introduce MPLS within our network backbone, among other
> things for QoS purposes. Our current concept is based solely on using EXP
> values for different priority levels (the IP TOS fields need to be left
> unchanged.)
>
> Aside from applications which require higher-than-normal forwarding
> priorities, we have a small number of traffic flows which we'd like to
> assign a lower-than-normal priority. As far as I can see, this would
> require an EXP value>  0 for standard traffic. More precisely, I'd need to
> set a specific default EXP value for all labels imposed on a MPLS router,
> regardless of interface etc. Are there easy methods to achieve this goal,
> preferably on the global configuration level?
>
> The only solution I've found so far is to impose that default EXP value
> via a service policy attached to the respective interfaces. But given the
> number of interface configs, this would be extremely cumbersome to manage,
> and additionally it would interfere with existing service policies. I
> think this is definitely not the way to go.
>
> Any suggestions regarding an alternative design would be also welcome.
> We're using c6500/Sup720/PFC3 devices with IOS version
> s72033-advipservicesk9_wan-mz.122-33.SXI3.
>
> Thanks for your advice,
> Patrick
>
>
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Hi,

I believe you shouldn't think that higher exp value traffic is always 
better than a lower value. As RFC 5127 states, exp 1 is recommended for 
less than best effort and exp 0 is default/best effort

So why not just let your standard traffic be default at 0 and put your 
less-than-best-effort to exp 1. Numbers really don't matter, aye? You 
just match what ever exp value you want and then have an action based on 
the match

/Lauri