[AusNOG] DSCP on internet services

Adrian Chadd adrian at creative.net.au
Wed Feb 17 19:53:49 EST 2010


There's also different behaviours based on what you're using. Don't the switches
default to rewriting the DSCP when you enable QoS, and that default itself
is also not consistent? :)



Adrian

On Wed, Feb 17, 2010, Balmik Soin wrote:
> Have seen this behaviour on Cisco routers before, traced it back to it being picky about which traffic types it will re-mark - for instance in this case, it wouldn't re-mark DSCP for IPSec traffic when it was being matched in the class-default catchall.
> 
> Assume this is some sort of "feature" in the IOS release being used on the router at the time :)
> 
> - Balmik.
> 
> 
> -----Original Message-----
> From: ausnog-bounces at lists.ausnog.net [mailto:ausnog-bounces at lists.ausnog.net] On Behalf Of Craig Meyers
> Sent: Wednesday, 17 February 2010 3:47 PM
> To: ausnog at ausnog.net
> Subject: Re: [AusNOG] DSCP on internet services
> 
> 
> FYI
> 
> Today as an example, on our netflow stats we receive 1-2% traffic marked with something other than zero.
> 
> So the odd non-zero flow gets through.
> 
> -- Craig Meyers
> 
> -----Original Message-----
> From: ausnog-bounces at lists.ausnog.net [mailto:ausnog-bounces at lists.ausnog.net] On Behalf Of McDonald Richards
> Sent: Wednesday, 17 February 2010 4:09 PM
> To: ausnog at ausnog.net
> Subject: Re: [AusNOG] DSCP on internet services
> 
> Yeah - the Internet ones ;)
> 
> Macca
> 
> 
> From: Phillip Grasso [mailto:phillip.grasso at gmail.com]
> Sent: Wednesday, 17 February 2010 5:00 PM
> To: McDonald Richards
> Cc: Raymond, Adam; ausnog at ausnog.net
> Subject: Re: [AusNOG] DSCP on internet services
> 
> I'm assuming your resetting dscp to 0 from your customers as well?
> 
> 
> On Wed, Feb 17, 2010 at 4:28 PM, McDonald Richards <macca at vocus.com.au>
> wrote:
> Agreed. Standard practice at every place I've worked has been to remark DSCP to 0 on ingress for all "Internet" traffic.
> 
> Macca
> 
> 
> From: ausnog-bounces at lists.ausnog.net
> [mailto:ausnog-bounces at lists.ausnog.net] On Behalf Of Phillip Grasso
> Sent: Wednesday, 17 February 2010 4:17 PM
> To: Raymond, Adam
> Cc: ausnog at ausnog.net
> Subject: Re: [AusNOG] DSCP on internet services
> 
> sorry let me be clear,
> resetting dscp bits to 0 (or other internal classify for best effort) is normal for large ISP's with internal qos policies. proper behaviour is to leave last two bits alone for ECN, but I doubt ecn bits are passed across the internet freely.
> On Wed, Feb 17, 2010 at 3:56 PM, Phillip Grasso <phillip.grasso at gmail.com>
> wrote:
> My understanding that is the de facto standard for most large SP's .
> Especially if they run their own qos policies internally.
> 
> On Wed, Feb 17, 2010 at 3:42 PM, Raymond, Adam <Adam.Raymond at nn.com.au>
> wrote:
> All,
> 
>             I am wandering if other networks modify the DSCP of internet customers when they receive the traffic from the customer (such as resetting it to BE for all traffic). What is seen as being "best practice" for this operation.
> 
> Regards,
> 
> Adam Raymond
> 
> IP Project Engineer
> NextGen Networks
> www.nextgennetworks.com.au
> Direct:   03 8623 3638
> Level 6, 333 Collins St
> Melbourne  VIC  3000
> 
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