3Com 10014299 manual Set broadcast via, Set interface with standby center, Address broadcast

212CHAPTER 16: CONFIGURING LAPB AND X.25

Generally, inter-network protocols will need to send some broadcast datagrams for specific purposes. On the broadcasting physical networks (such as Ethernet), such requirements are naturally supported. But for non-broadcasting networks like X.25, how to realize the broadcasting?

The X.25 of the 3Com Router series can enable this to decide if the broadcast packet should be duplicated and sent to a destination. This is very important. For instance, the broadcast-based application layer routing protocol will request broadcasting datagram sent by X.25 to exchange routing information on the X.25 network.

It can be specified whether to send broadcasting data packets on the related virtual circuits of both SVC and PVC.

Table 253 Set broadcast via X.25

Operation	Command
Enable to send broadcasting data packets to	x25 map protocol
the peer of the SVC associated with this	protocol-address
address mapping	x121-address x.121-address
	broadcast
Enable to send broadcasting data packets to	x25 pvc pvc-number protocol
the peer of this PVC	protocol-address x121-address
	x.121-address broadcast

7Restrict the use of address mapping

X.25 calls are closely related to address mapping: before a destination is called, this destination must be found in the address mapping table. Before a call is received, the source of this call must also be found in the address mapping table. But in some cases, some address mappings are used for calling out only, while others are used for calling in only.

The X.25 of the 3Com Router series allows restricting the use of this address mapping addition by adding some option items, as shown in the following table.

Table 254 Restrict the use of address mapping

Operation	Command
Inhibit outgoing call through this address	x25 map protocol protocol-address
mapping	x121-address X.121-address
	no-callout
Inhibit incoming call through this address	x25 map protocol protocol-address
mapping	x121-address X.121-address
	no-callin

8Configure interface with standby center

The powerful standby function of the 3Com Router series is provided by the "standby center". To add an X.25 interface into the standby center, perform the following task in the interface view.

Table 255 Set interface with standby center

Operation	Command
Set the logical interface number of this address	X25 map protocol
mapping in the standby center	protocol-address x121-address
	x.121-address logic-channel
	logical-interface-number