Operating System - OpenVMS

Decnet TP4 vs NSP. Is one better than the other?

Jan Andersson_3
Occasional Advisor

Decnet TP4 vs NSP. Is one better than the other?

Hi there.

We have had some issues with some nodes not being able to reach other nodes. That was a name resolution problem which was temporary and solved by flushing the caches.

I am now cleaning up the decnet configuration in all systems.

The goal is to have only one address on each system. We now have both NSP and TP4 addresses on each system.

We don't have any Decnet phase IV nodes anymore.

The namespace is Local.

On our testsystems I now have only  phase V NSP addresses. No TP4, Decnet IV or Decnet over IP configured.

Before reconfigure of the production nodes I have this question:


Would TP4 (ISO) be a better choice?


Another question:

Decnet_register defaults to Session Control V2 (SC2) when register NSP addresses.

I there a way to set SC3 manually in Decnet_register?  I have not found any way to do that.



Honored Contributor

Re: Decnet TP4 vs NSP. Is one better than the other?

If you're not using DECnet over IP nor multiple connection per host, then do consider upgrading Phase V to Phase IV; from the somewhat unstable and cryptically-managed behemouth to the dinky DECnet stack that "just works."


Re: Decnet TP4 vs NSP. Is one better than the other?


> Would TP4 (ISO) be a better choice?

I think that depends on what your requirements and your preferences are.

I have a customer (service provider) that ensures that all interactive sessions are LAT, all internal access is via DECnet (NSP) (as far as possible) and all his external application connections use OSI TP..

Before deciding on NSP or TP4, try measuring the performance using DTSEND.I know that DECnet engineering had to do some work with regard to alignment faults on IA64

Are cluster alias addresses important for you, if yes then that would rule out DECnet over IP (RFC 1859).

As far as troubleshooting is concerned I find it easier to analyze problems with TP4 than NSP.


DECnet Register Question.

I export my Node definitions to a file, edit the file eg. SC2=>SC3 and then import the file.