3Com 10014299 manual Configure the X.25 Attributes for a Dlci

222CHAPTER 16: CONFIGURING LAPB AND X.25

When configuring an Annex G DLCI, the user must explicitly configure it with the argument DCE or DTE. In addition, the configurations on the routers of a connection should not be the same. That is, if a router is configured to work as DTE, the other router must be configured as DCE.

Table 271 Configure the X.25 attributes for an Annex G DLCI

Operation	Command
Create an X.25 template	x25	template	{ name }
Configure the local X.25 address in the X.25	x25	x121-address x.121 address
template
Map the destination X.25 address to the	x25	map ip { A.B.C.D } {
destination IP address in the X.25 template	x121-address		x.121 address }
Configure other LAPB/X.25 parameters in the	For details,		refer to the
X.25 template	LAPB/X.25 configuration commands.
Associate the parameters configured in the	x25-template		{ name }
X.25 template to an Annex G DLCI

It is necessary to properly understand the differences between the Frame Relay address map configured in interface view and the X.25 address map configured in X.25 template view. The former specifies the DLCI from which the packets destined to an IP address can be sent, whereas the latter specifies the X.25 address to which the packets must originate X.25 calls in order to reach the destination IP address. IP packets can be properly sent and received on the Annex G DLCI only if the two address maps are configured.

The LAPB/X.25 attributes configured in an X.25 template and those configured on an X.25 interface are similar. To ensure that an X.25 call can be set up, the configurations on the routers of a connection should keep in consistency.

1Configure the X.25 Attributes for a DLCI

Frame Relay is mainly applied to data transmission. However, it does not provide acknowledgement mechanism or error correction function. In other words, transmission over Frame Relay networks is unreliable. To ensure reliable transmission of signals for call set up and termination in dynamic calling mode, these signals are transmitted over an X.25 VC (Virtual Circuit). Thereby, reliable transmission can be ensured through the X.25 message acknowledgement mechanism. A DLCI needs to be configured with X.25 attributes only when VoFR (Voice over Frame Relay) adopts dynamic calling mode.

The x.25 template command is performed in system view. Creating an X.25 template will enter x.25 template mode at the same time. Perform the commands x25 and lapb in x.25 template mode, and x25-templatein interface DLCI mode.

Table 272 Configure the X.25 attributes for an DLCI

Operation	Command
Create an X.25 template	x25 template name
Delete the X.25 template	no	x25 template name
Configure the X.25 attributes	x25
Restore the X.25 attributes to default settings	no	x25
Configure the LAPB attributes	lapb
Restore the LAPB attributes to default	no	lapb
settings
Associate the X.25 template with a DLCI	x25-template name
Remove the association between the X.25	no	x25-template
template and the DLCI