A T1 or E1 port can be configured to provide a subrate PPP service. That is, by using a channel group, the PPP service can be assigned to a subset of the timeslots that are available on the T1 or E1 port. Only one channel group can be configured per port for subrate PPP.
The following cards and platforms support fractional T1/E1 on a PPP channel group (encapsulation type ppp-auto), or all timeslots on T1/E1 ports, in network mode:
16-port T1/E1 ASAP Adapter card
32-port T1/E1 ASAP Adapter card
T1/E1 ports on the 4-port T1/E1 and RS-232 Combination module (on 7705 SAR-H)
T1/E1 ports on the 7705 SAR-A
T1/E1 ports on the 7705 SAR-M
T1/E1 ports on the 7705 SAR-X
You must then change the value of the timeslot configuration to specify the number of timeslots you want to use. Any timeslots not selected cannot be used.
Use the following CLI syntax to configure a T1/E1 port for fractional T1/E1.
First, configure the port:
port port-id
tdm
e1
channel-group channel-group-id
encap-type ppp-auto
mode network
no shutdown
exit
no shutdown
exit
exit
no shutdown
Use the config port info command to display port configuration information:
*A:ALU-A>config>port# info detail
----------------------------------------------
description "DS1/E1"
tdm
e1
shutdown
framing g704
no loopback
clock-source node-timed
no signal-mode
report-alarm ais los
no report-alarm oof rai looped ber-sd ber-sf
no hold-time
ssm
shutdown
ssm-bit 8
no tx-dus
channel-group 1
shutdown
description "DS0GRP"
mode network
encap-type ppp-auto
no mtu
network
queue-policy "default"
exit
timeslots 2-32
crc 16
idle-cycle-flag flags
no scramble
ppp
keepalive 10 dropcount 3
exit
exit
exit
line-impedance 120
exit
no shutdown
Next, change the value of the timeslots configuration (currently, all timeslots are allocated to this channel group):
port port-id
tdm
e1
channel-group 1
timeslots 11-20
Use the config port info command to display the new port configuration information:
*A:ALU-A>config>port# info detail
----------------------------------------------
description "DS1/E1"
tdm
e1
shutdown
framing g704
no loopback
clock-source node-timed
no signal-mode
report-alarm ais los
no report-alarm oof rai looped ber-sd ber-sf
no hold-time
ssm
shutdown
ssm-bit 8
no tx-dus
channel-group 1
shutdown
description "DS0GRP"
mode network
encap-type ppp-auto
no mtu
network
queue-policy "default"
exit
timeslots 11-20
crc 16
idle-cycle-flag flags
no scramble
ppp
keepalive 10 dropcount 3
exit
exit
exit
line-impedance 120
exit
no shutdown
----------------------------------------------
*A:ALU-A>config>port#