🚀 go-pugleaf

In article <jjr.720993680@gw.alantec.com>, jjr@alantec.com (Janardan Ramesh) writes:
> I am in the process of implementing DECNET phase-IV routing. When a node is
> configured as a level 2 router, it is necessary to assign a different node ID
> for each area the router is connected to? Should the router maintain a
> different routing data base for each area? These concepts have not been
> addressed clearly in the routing specification.
> 
> The configuration I was referring to, is shown below:
> 
> 
>     --------------------------- (area 1)
> 		  |
> 	 ------------------- 
> 	| Router            |
> 	 -------------------
> 		  |
>     --------------------------- (area 2)


Sorry, but this configuration won't work. You must have an area router in each
area and they must be connected. So you end up with:

      
    --------------------------- (area 1)
		  |
	 ------------------- 
	| Router (1.x)      |
	 -------------------
		  |
	 ------------------- 
	| Router (2.x)      |
	 -------------------
		  |
    --------------------------- (area 2)

Of course, each area router may connect with more than one other area.

The node number portion of the address of the router is not significant unless
there are more than one path between areas with identical cost. In that case
the router with the highest address will be used. Please note that this can
easily result in asymetrical routes if you don't assign addresses correctly.

Also, unlike IP, DECnet assigns addresses to nodes, not interfaces.

I'm not clear on just what you mean by "routing data base". The routing data
base is built by the routers. You don't maintain anything. If you mean the
database of node names to addresses, you normally have only one unless you are
doing something unusual. All nodes should copy this single database to their
own systems on a regular basis.

But this data base is only for human interface. Routing makes no use of it nor
does any part of DECnet except the user interface and the odd case of "poor
man's routing" (PMR).

R. Kevin Oberman			Lawrence Livermore National Laboratory
Internet: koberman@llnl.gov		(510) 422-6955

Disclaimer: Don't take this too seriously. I just like to improve my typing
and probably don't really know anything useful about anything.