System information

Troubleshooting DECnet 11-267
DECnet: No Phase IV Connectivity over Phase V Backbone
DECnet Phase IV and ISO CLNS Addresses
Address conversion between DECnet Phase IV and ISO CLNS (Phase V) requires that NSAP
addresses be Phase IV compatible. If an address can be converted to a valid Phase IV address, it is
Phase IV compatible.
To be compatible, the OSI area number must be between 1 and 63 (when converted to decimal) and
the OSI station ID must be in the format AA00.0400.xxxx. In addition, the OSI area and the DECnet
area (calculated from the OSI station ID) must match. This allows the DECnet Phase IV address to
be extracted properly from the NSAP.
Table 11-8 shows addresses and their equivalent DECnet Phase IV addresses, and indicates whether
the NSAP address is Phase IV compatible and why.
Possible Problem Solution
Misconfigured addresses
Step 1 Use the show interfaces command to confirm that CLNS and
DECnet Phase IV are both configured on ISO CLNS backbone
routers.
Step 2 Make sure that the decnet conversion global configuration
command is configured on backbone routers to allow DECnet Phase
IV–to–ISO CLNS conversion.
Step 3 Use the show running-config privileged exec command on
backbone routers to verify that DECnet addresses agree with CLNS
addresses.
Two kinds of addresses are easily misconfigured: DECnet addresses,
which should be specified in decimal, and CLNS Network Service
Access Point addresses, which should be specified in hexadecimal.
For more information, refer to the section “DECnet Phase IV and
ISO CLNS Addresses” later in this chapter.
Step 4 If the area addresses do not agree, confirm the address specifications
and reconfigure the DECnet and CLNS addresses on the router.
For detailed information on configuring DECnet Phase IV, CLNS, and
conversion, refer to the Cisco IOS Network Protocol Configuration Guide,
Part 2.
ISO CLNS or DECnet not enabled
on appropriate interfaces
Step 1 On Phase IV routers bordering the backbone, use the show clns
interface and show decnet interface commands to see which
interfaces are running which protocols.
Verify that DECnet and ISO CLNS are enabled on backbone router
interfaces where conversion will occur.
Step 2 If DECnet is not configured on the correct interfaces, enable it. Make
sure you specify the decnet cost interface configuration command to
assign a cost to the interface. If ISO CLNS routing is not configured
on the correct interfaces, use the clns router interface configuration
command. The full syntax for this command is
clns routing
Use the no clns routing command to disable CLNS routing:
no clns routing
For detailed information on configuring DECnet Phase IV and ISO CLNS,
refer to the Cisco IOS Network Protocol Configuration Guide, Part 2.