HP Network Direr Software Products manual Key Considerations

Key Considerations 143

■Routing: It uses MIB II tables to establish if the device has IP-forwarding enabled and has interfaces on multiple subnets. If so it is flagged as a router and will appear on the map at the top level with a diamond border. See “Working with the Map” on

page 151.

■Switching: It attempts to read the dot1dBaseType from the bridge MIB. If this is present it is flagged as a switch and will appear with an octagonal border on the map. See “Working with the Map” on page 151.

For third party switches 3Com Network Director reads bridge FDB tables during the topology process. However, it does not attempt to retrieve spanning tree information for these devices.

No attempt is made to determine the topology of third party hubs. They will simply be treated as end stations by the topology process.

3Com Network Director attempts to determine the manufacturer of third party devices, only if they support SNMP. However, it does attempt to determine the type of certain end stations, such as Unix workstations.

Key Considerations

Discovering over If you are discovering a remote subnet over a slow link you may find that slow/expensive links 3Com Network Director encounters many timeouts when communicating with the remote devices. Also, you may find that the traffic generated by

3Com Network Director is consuming a significant amount of the bandwidth, thus impacting other users of the connection.

If you are concerned about consuming bandwidth, it is generally better to increase the timeout values 3Com Network Director uses, rather than increasing the number of retries. By increasing the timeouts, 3Com Network Director will wait longer for the responses from the devices, and also by waiting longer it means there are periods during which other traffic can use the link. Increasing the number of retries would simply generate more traffic since 3Com Network Director would be resending its requests while the initial responses are coming back.

If you are less concerned about consuming bandwidth, but more concerned about the actual time a link is open (i.e. due to its cost) then you may consider that increasing the number of retries is also an option.