[HECnet] What use are *you* making of HECnet?

[Paul Koning]

"gerry" == gerry   <gerry77 at mail.com> writes:

gerry> Really, we [1] had some problems with fragmented UDP packets,
gerry> mostly due to some cheap IP routers bundled with local ADSL
gerry> connections. Many of them seem to be unable to correctly
gerry> manage UDP fragments and/or have memory leaks which in the end
gerry> cause lockups and other nasty things after some DECnet-in-UDP
gerry> traffic has passed thru them. In at least one case, the
gerry> problem was even nailed down to some ISP apparatus sitting
gerry> between two remote bridges of ours.

Yikes.

gerry> We still do not know how these UDP related problems would/will
gerry> impact other protocols like LAT, LAD/LAST and MOP because we
gerry> haven't experimented so much as with pure DECnet. Any
gerry> contribution and suggestions on how to force reduced frame
gerry> size for those protocols would be much appreciated. :-)

I can't think of any.   The general rule at DEC was that some basic
level of design competence was assumed.   Getting the Ethernet frame
size right was certainly part of the basic IQ test.

The only solution I can think of is to reduce the MTU of your local
Ethernet on the machine doing the UDP encapsulation.   That would force
the packets to be fragmented at origination time, which means your
defective routers will see small-enough packets.

	  paul