[HECnet] QNA Data overrun (Was: Same MAC address)

[Jean-Yves Bernier]

At 2:14 AM +0200 26/5/14, Johnny Billquist wrote:

Aha. So it is 10.2 that gets timeouts when sending packets to 10.1. So 10.1 are dropping packets.

Good. Now, in which direction was the transfer attempted?

10.2 -> 10.1, initiated from 10.1:

10.1>NFT TI:=10.2::SOME.FILE


This is a problem inside of DECnet on the simulated host. It gets packets faster than it can process them, so some packets are dropped.
Unfortunately DECnet deals very bad with systematic packet loss like this. You get retransmissions, and after a while the retransmission timeout backs off until you have more than a minute between retransmission attempts.

I have now to find the reason for the packet loss.


Anyway, if you can get simh to throttle the ethernet interface, that might help you. (I don't remember offhand if it do support such functionality.)

The service   polling timer can be adjusted

SET XQ POLL={DEFAULT|4..2500}

Set to 100 by default.


-- 
Jean-Yves Bernier