Re: [Cerowrt-devel] Ubiquiti QOS

[Michael Richardson <mcr@sandelman.ca>]

David P. Reed <dpreed@reed.com> wrote:
    > ECN-style signaling has the right properties ... just like TTL it can
    > provide

How would you send these signals?

    > A Bloom style filter can remember flow statistics for both of these local
    > policies. A great use for the memory no longer misapplied to
    > buffering....

Well.

On the higher speed dataflow equipment, the buffer is general purpose memory,
so reuse like this is particularly possible.

On routers built around general purpose architectures, the limiting factor
in performance is often memory throughput; adding memory rarely increases
total throughput.   Packet I/O is generally quiet sequential and so makes
good use of wide memory data paths and multiple accesses per address cycle.
Updating of tables such as Bloom filter or any other hash has a big impact
due to the RMW and random access nature.

All I'm saying is that quantity of memory is seldom the problem, but access
to it, is.

I do like the entire idea; it seems that it has to be implemented at the
places where the flow converge, which is often in the DSL line card, or
CTMS...

--
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]   Michael Richardson, Sandelman Software Works        | network architect  [
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