This section contains the following information to help you
plan for using DECdtm in a DECnet-Plus network:
Planning your
DECnet-Plus namespace
Planning SCSNODE names in
your DECnet-Plus network
Planning
Your DECnet-Plus Namespace DECdtm does not support multiple DECnet-Plus namespaces.
This means that if you want to use software that uses DECdtm
services, you cannot use both a local namespace and a DECdns namespace.
Planning
SCSNODE Names in Your DECnet-Plus Network SCSNODE is a system parameter that defines the name of the
computer. You must follow certain rules when choosing SCSNODE names
if you have a DECnet-Plus network and you want to perform DECdtm transactions
that span either different OpenVMS Clusters or different standalone
computers.
Rules for SCSNODE Names If you have a DECnet-Plus network and want to perform DECdtm
transactions that span different OpenVMS Clusters or different standalone
computers, you must make sure that your SCSNODE names obey the following
rules:
The SCSNODE
name of each computer in a transaction group must be different from:
The
SCSNODE names of the other computers in the transaction group; SCSNODE
names must be unique within a transaction group
The DECnet simple names of
other computers on the same local root
The DECnet synonyms of the
other computers in the entire network
If a computer is in an OpenVMS
Cluster, its SCSNODE name must also be different from:
The
DECnet simple name of the other computers in the same cluster
The DECnet simple names of
computers on the same local root as other cluster members
Understanding
Transaction Groups A transaction group is a group of computers
involved in DECdtm transactions whose SCSNODE names must obey the
rules described in
Rules for SCSNODE Names.
A transaction group conforms to the following guidelines:
Each computer
belongs to no more than one transaction group.
All the computers in an OpenVMS
Cluster belong to the same transaction group.
If a single transaction spans
computers A and B, then computers A and B belong to the same transaction group.
All nine computers shown in the figure are in the same transaction
group because:
A transaction spans a computer in
cluster FRED and a computer in cluster BILL. This means that the four
computers in cluster FRED and the four computers in cluster BILL
are in the same transaction group.
A transaction spans standalone computer TOM and
a computer in cluster BILL. This means that the standalone computer
TOM is in the same transaction group as the computers in cluster
BILL.
HP OpenVMS System Manager's Manual, Volume 2:... 
Managing DECdtm Services
