Isdn Bri Interface - 3Com 3032 Configuration Manual

128 C 10: C
HAPTER ONFIGURING

ISDN BRI Interface

WAN I
NTERFACE
12 Configure MTU
MTU of synchronous serial interface affects the fragmentation and reassembling
of IP network protocol message on this interface.
Please use the following commands in the view of the synchronous serial
interface.
Table 121 Set MTU of synchronous serial interface
Operation
Set MTU of synchronous serial interface
Recover the default value of MTU
The unit of mtu is byte, ranging between 128-1500, with 1500 as default.
13 Configure the time interval for sending keepalive packets
The serial interface will send keepalive packets to the opposite end at every
keepalive interval to check if the link is in normal state or not.
Perform the following configuration in serial interface view.
Table 122 Set the time interval for sending keepalive packets
Operation
Set the time interval for sending keepalive packets timer hold seconds
Disable keepalive packet sending
The time interval for sending keepalive packets is 10 seconds by default.
CAUTION: When the serial interface is encapsulated with HDLC protocol, the
keepalive interval set on both ends of the link must be the same.
14 Set the idle coding of synchronous serial interface
Perform the following configuration in serial interface view.
Table 123 Set the idle coding of synchronous serial interface
Operation
Set the idle coding of synchronous serial interface
to "FF"
Restore the idle coding of synchronous serial
interface to "7E"
The idle coding of synchronous serial interface is "7E".
Technical Background
Integrated Services Digital Network (ISDN) is a new technology developed from
the 1970's. It can provide all-digital services from terminal user to terminal user
and fulfill an all-digital transmission mode integrating services such as voice, data,
graphics and video.
ISDN is different from conventional PSTN. In conventional PSTN, information is
sent to the switch via analog user loop, converted to digital signal through A/D
conversion and then resumed to analog signal when reaching the destination user.
ISDN realizes the digital transmission of user loop to implement digital end-to-end
communication. This will enable various digital and analog information to transmit
via the standard digital interface. Besides, ITU-T standardizes ISDN services and
formulates such recommendations as I.430, Q.921 and Q.931 to make any
Command
mtu size
undo mtu
Command
undo timer hold
Command
idle-mark
undo idle-mark