tlambert2 at mindspring.com
Thu Sep 18 02:08:06 PDT 2003
Deepak Jain wrote:
> Is there a utility/hack/patch that would allow a diligent sysadmin to obtain
> which specific TCP connections are generating retransmits and receiving
> packet drops? netstat will show me drops on an interface, but not on a
> specific source/dest pair?
> I am guessing something like a netstat -n, but instead of showing send/rec
> queues it shows retransmit or packet drops? Would there be much interest in
> this feature if we were to build it ourselves?
These types of statistics aren't kept.
Generally, they are used only by network researchers, who hack
their stacks to get them.
They usually do not make it into commercial product distributions
for performance reasons, and because every byte added to a tcpcb
structure is one byte less that can be used for something else.
In practice, adding 134 bytes of statistics to a tcpcb would
double its size and halve the number of simultaneous connections
you would be able to support with the same amount of RAM in a
given machine (as one example), if all of that memory had to
come out of the same space, all other things being equal.
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