topic Outbound Discards -- Definition? in Operating System - HP-UX

Outbound Discards -- Definition?

Darren Besler — Mon, 06 Nov 2000 16:47:01 GMT

Can someone explain precisely what an outbound discard is? And what are the conditions by which they occur?

Outbound discards are noted in lanadmin output.

Re: Outbound Discards -- Definition?

Ian_4 — Mon, 06 Nov 2000 23:00:49 GMT

- The Packets Outbound Discarded is the number of outbound packets that were chosen to be discarded even though no errors had been detected to prevent their being transmitted.
One possible reason for discarding such a packet could be to free up buffer space.

- The Datagrams Outbound Discarded is the number of output IP datagrams for which no problems were encountered to prevent their transmission to their destination, but which were discarded (for example, for lack of buffer space.)
This counter would include datagrams counted in Datagrams Forwarded if any such packets met this (discretionary) discard criterion.

Hope this helps,

Ian.

Re: Outbound Discards -- Definition?

rick jones — Mon, 20 Nov 2000 20:49:16 GMT

99 times out of 10, an outbound discard is logged in lanadmin (interface MIB) stats because the driver's outbound transmit queue was full.

if you see this happening frequently, you may also want to check the statistics of TCP with netstat and see what sort of TCP retransmission rate you have.

a consistently full outbound transmit queue implies either an overloaded NIC or an overloaded network connection. in such cases, lanadmin statistics should also show a non-zero outbound queue length much of the time.