3Com Router 3031, Command Reference Manual

Page: 377 / 838

LAPB and X.25 Configuration Commands 377
Normally, the maximum receiving packet length is equivalent to the maximum
send packet. Unless users' ISP allows, please do not set these two parameters to
different values.
For the related commands, see x25 call-facility, x25 pvc, x25 switch pvc, x25 xot
pvc and x25 fr pvc.
Example
Set the maximum receiving packet length and maximum sending packet length
on X.25 interface Serial0/0/0 to 256 bytes.
[3Com-Serial0/0/0] x25 packet-size 256 256
x25 pvc
Syntax x25 pvc pvc-number protocol-type protocol-address x121-address x.121-address [
option ]
undo x25 pvc pvc-number
View
Interface view
Parameter
■
pvc-number: PVC number, which must range from 1 to 4095 (including 1 and
4095), and must be in the PVC channel range.
■
protocol-type: Upper-layer protocol carried over the permanent virtual circuit,
which may be IP or compressedtcp.
■
protocol-address: Network protocol address of the peer end of the PVC.
■
x.121-address: X.121 address of the peer end of this PVC.
■
option: Attribute of the PVC.
Description
Using the x25 pvc command, you can configure one PVC route encapsulated with
datagram. Using the undo x25 pvc command, you can delete this route.
By default, no PVC encapsulated with datagram is created. When creating such a
PVC, you do not set the relevant attributes for the PVC, its flow control
parameters will be the same as that of the X.25 interface on which it resides (the
flow control parameters on an X.25 interface can be set by the x25 packet-size
and x25 window-size commands).
As one corresponding address mapping is impliedly established while establishing
the PVC, it is unnecessary (or impossible) to establish an address mapping first
before establishing PVCs.
Before establishing PVCs, users should first enable the PVC channel section. The
section is between 1 and the latest unprohibited channel section PVC number
minus 1 (including 1 and the lowest PVC number minus 1). Naturally, if the lowest