QoS/CoS in the real world?

Tue Jul 16 08:00:42 UTC 2002

At 11:13 AM 7/15/2002 -0400, Art Houle wrote:

>We are using QOS to preferentially drop packets that represent
>file-sharing (kazaa, gnutella, etc).  This saves us 40Mbps of traffic
>across our multiple congested WAN links.  The trick is to mark packets
>meaningfully.  Also, the WFQ introduces some additional latency at our
>edge.

That's exactly the right phrase: "We are using QOS to preferentially drop 
packets...."

When my research customers come to me wanting QoS, I can usually screen out 
the silly requests from the serious requests by asking "OK how can I tell 
which packets are less important and should be dropped?"

If they say "someone's packets other than mine" I nod and smile politely.

However, the Access Grid application runs both video and audio.  The AG 
folks can very easily mark the packets for video and audio, and are quite 
happy to drop video packets in order to get the audio clear.  AG users 
really truly want good audio at the expense of high quality video.

To this point we haven't actually implemented it, but it's a nice option to 
have in one's back pocket to pull out when it's really needed.

===
Bill Nickless    http://www.mcs.anl.gov/people/nickless      +1 630 252 7390
PGP:0E 0F 16 80 C5 B1 69 52 E1 44 1A A5 0E 1B 74 F7     nickless at mcs.anl.gov