DECNET through the routers (CISCO and Marconi)

[mike_695]

Environment:
OpenVMS 7.2-1, 10 Alpha 4100s, DECNET IV
One OpenVMS is in the Central Computing Room and acting as DECNET Router.
The other nine nodes are in other field buildings.

This is/was a FLAT network (i.e. no routers).
Everything has been working fine, for years.

Now, they started replacing the network infrastructure.

After they moved one of the end nodes onto the new network (which has a CISCO 7000 amd Marconi BXR-5000 routers and Alcatel switches), the end node cannot communicate any more using DECNET with the central DECNET node. IP works fine.

I tried to talk to network people, but they don't know anything about DECNET.
They claim that Alcatel switches forward everything to the new routers.

My question is, will DECNET on the end node be "smart" enough (providing that the new routers allows DECNET through)to find a path through the new network/routers to our central DECnet node which is still on the old network ?

How will DECNET do that (I.e. find the new Pnath) ? What protocols does it use for that.

TIA

[Karl Rohwedder]

Mike,

if the routers don't understand DECnet, they will not pass any DECnet messages and you will have no connectivity.
This seems to be a trend, that only TCPIP will be supported by 'the network people'.
Our solution to this was the switch to DECnet Phase V and DECnet-over-IP, i.e. DECnet uses the TCPIP protocol suite for the lower layers, while our normal DECnet functionality (transparent file access, task-to-task...) remains intact. Works well and was quite easy to configure.

regards Kalle

[mike_695]

Thanks Kalle, but we have to stay on VMS 7.1-2 and DECNET IV.

Can I run DECNET over TCPIP with these versions ?

[Karl Rohwedder]

Mike,

I think, that one of the alternate Ip-stacks (TCPware or multinet) supports DECnet/IP with Phase IV, check there.
But switching the IP stack may be more hazzle than switching from phase IV to V.

regards kalle

[Jan van den Ende]

Mike,

not knowing the exact specs of a Cisco 7000, I will have to do some guesswork, but it is now quite common for Cisco;s to NOT pass DECnet (IV & V) protocils, UNLESS a (rather pricey) special license is purchased. nd even then there is the "little" matter of convincing your network people. (technically it is all quite simple, but...)

As far as I am aware, Cisco nowadays also has switches that do not even have the ability anymore. If that is true for the 7000, that would mean either convincing "networks" to change their choice, OR, moving to Decnet V-over-IP (and having "networks" open up port 200 & 399 )

Good luck!

Proost.

Have one on me.

jpe

[Richard Whalen]

MulitNet and TCPware both support configuring a software interface that encapsulates the DECnet packets in IP packets. In both cases the software interface is a virtual point to point link, so the systems would need routing licenses. MultiNet also offers DECnet Application Services, which looks like DECnet to programs but is really done totally over IP and does not require a DECnet routing license.

[Colin Butcher]

Sounds as if you've been moved to an IP routed network rather than an extended LAN layer 2 network or a multi-protocol routed network (DECnet and IP routed, the layer 2 stuff probably bridged). Is there a good reason why?

What other protocols were in use betwen the nodes, for example LAT, MOP, SCS etc.? All of those will probably stop working too if it's an IP routed core. Why? Because they're layer 2 protocols.

You could move to DECnet Phase V in Phase IV compatible mode and use DECnet over IP between the nodes. You could use a 3rd party IP stack that encapsulates Phase IV packets.
Both work. I've tended to use DECnet Phase V in Phase IV compatible addressing mode and found it to work well and not had to make changes to the applications.

You could try enabling bridging of non-IP traffic between the new routers - if the networks people will co-operate. It's kind of difficult to give a "best course of action" recommendation without looking at it in a little more detail.

If you go the DECnet over IP route then you might find this useful: http://www.downloads.xdelta.co.uk/vmstjv5%20feb2005/decnet%20article%20vms%20tj%20v5%20feb2005.pdf

Good luck.

Cheers, COlin (http://www.xdelta.co.uk).

[DECxchange]

Hello,
If you switch to DECnet OSI Phase V, it is backward compatible with Phase IV. I think all you would have to do is include the phase IV routing code in your address stack using the @sys$manager:net$configure utility. Then you might have to add the DECnet nodes names in sys$system:decnet_register. But anything after VMS 7.3, I think they recommend using Phase V.

But even after that, there may be something in that Cisco router that does not route DECnet. You might have to get the network administrator to configure the Cisco router to route DECnet.

[Andy Bustamante]

The Cisco 7000 is an older router, it may support DECnet without licensing. Under Cisco's newer business model, using DECnet is premium or even unsupported. I've used 4000 and 2000 series routers to move DECnet with no special licensing.

Your network group will need to configure DECnet on each interface and you'll need probably need to update the end node to reflect a new DECnet area number.

DECnet isn't generally supported in a Cisco configure script. This link provides some addtional information. http://www.cisco.com/en/US/docs/ios/11_0/router/command/reference/rdecnet.html#wp305 I suspect the biggest issue will be getting the network group to admit there is valid network traffic that isn't using tcp/ip or udp.

Andy

[mike_695]

Thank you all !

At this moment, I'll ask the network guys to configure bridging for these DECENET nodes.