Joel Apisdorf wrote:
>
> >In general the packet pair
> >algorithm is very hard to apply to TCP in its startup phase. The reason is that
> >because of the receiver delaying the ACKs, two packets sent back to back (as
> >required by packet pair) wouldn't necessarily cause the receiver to respond
> >with an ACK for each immediately. In fact the ACK spacing can be such that you
> >end up grossly *underestimating* your bandwidth.
>
> Assuming no past traffic has gone between the host pair to give you bandwidth-
> delay measurements to remember (say in a routing table), would it appropriate
> to use something other than TCP (say ICMP echo request) to get the packet pair?
>
> Apologies in advance if I am violating a separation of powers ;)
>
> Joel
Remember one other thing: If there is a WAN link in your connection,
and the link has gone down because of an inactivity timer, the first
packet will take a long time (seconds), because the WAN link needs
to dial out again. There are probably other types of `cache miss'
effects for the first packet.
--
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* Jacob Heitz Tel:510-747-2917/Fax:2859 home:510-888-9429 *
* Ascend->Engineering->Software->Alameda mailto:[email protected] *
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This archive was generated by hypermail 2b29 : Mon Feb 14 2000 - 16:14:43 EST