[HECnet] "Dropped by adjacent node" ....

[Paul_Koning at Dell.com]

On May 27, 2014, at 4:04 PM, Johnny Billquist <bqt at softjar.se> wrote:

On 2014-05-27 21:48, Bob Armstrong wrote:
The way to run DECnet over a flaky long distance network is to use point
to point mode with a data link layer that deals with packet loss.

  Probably a good idea, but we don't have that option on HECnet.

Well, HECnet is not a static piece of equipment. Anything is possible...
My bridge emulates a simple ethernet segment. Good enough many times, but if we have a link like yours, that sometimes seems to drop packets, then maybe some other alternative should be considered.

Now, the question then becomes, what can we do in this case.

As far as I understand, links using Multinet are more broken, and still use UDP. The same would appear to possibly be the case for Cisco as well?

Do anyone run any links using TCP?

That would work.   DDCMP over UDP would work.

GRE bridging of Ethernet packets is reasonable because that bridges a datagram service over a datagram service.   Usually the Internet is good enough for that to work.   Multinet is a much worse option, because it tunnels what it pretends is a point to point link over UDP, without actually implementing any datalink protocol to cope with the mismatch.

DDCMP in a user mode router would not be all that big a job.   In Python, even less.   Time to accelerate that effort.

	paul