On Fri, 8 Feb 2002, Deepak Jain wrote:

...

Another area which needs improvement is making L2 switches similarly aware of community TOS in IP packets.

Why would an L2 switch need or even want to be aware of TOS? Wouldn't this be a Class 3/4..7 issue? If community TOS is supported, those guys that would benefit from awareness of it in their internal network would address this at a higher level switch I'd think.

Well, maybe, but L2 switches do queueing and drops as well, so there should be some way to indicate which packets to drop, and which to keep. This means that they should be able to look deeper inside frames to extract information for frame classification. (Of course, a cleaner architecture would simply map L3 TOS into some L2 TOS bits at the originating hosts, but this just didn't happen...) One may argue that L2 switches typically are not bottlenecks, and the Internet access circuits effectively limit Ethernet utilization for the exterior traffic. However, there's a potential class of applications in clustered community computing (quite a lot of scientfic simulations, actually) which can generate very high levels of intra-cluster traffic.

I took your suggestion as a "best effort" below "normal" effort for "community" TOS. I could be mistaken.

That is exactly what i had in mind. --vadim