[e2e] Question on XCP

Aaron Falk falk at ISI.EDU
Thu Feb 10 13:29:37 PST 2005


The simplest, albeit imperfect, approach is to add a field in the
packet header which each XCP-capable router would decrement.  If the
change in this field was less from the change in TTL, the endpoints
would be aware that some routers were not practicing XCP.  This is
imperfect since tunnels would hid hops which might be practicing XCP
and non-router queues might not be detectectable at all using this

Strictly speaking, though, for XCP only the bottleneck router needs to
be running the algorithm.  Non-XCP queues which never congest need not
participate.  Of course, the trick is knowing which is which.  :)

You can find more on our XCP work at http://www.isi.edu/isi-xcp .



Arjuna Sathiaseelan wrote:
> Dear All,
>   I would be very much obliged if anyone could let me know how a XCP
> sender determines whether all the routers in its path is XCP
> enabled?  The XCP sender works only if all the routers in its path
> are enabled with XCP.
> I have a mechanism similar to XCP which requires all the routers in
> its path to be enabled with the mechanism proposed by me. Thanks.
> Regds,
> Arjuna

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