для Cisco Cisco IOS Software Releases 12.2 B

The software assumed that the 24th (or 16th for E1) slot in the controller is reserved for D-channel 
signaling. However, in environments that require SS7-enabled Voice over IP (VoIP) configurations, some 
applications needed to share all time slots in a PRI group but were not allowed to use the 24th (or 16th) 
time slot. The ISDN PRI-SLT Cisco IOS Release 12.2(8)B feature, and specifically, the rlm-group 
subkeyword introduced in the pri-group timeslots controller configuration command as part of this 
feature, releases the signaling time slots, thereby supporting SS7 applications in VoIP configurations.

The following ISDN commands are supported on the D-channel interface to configure ISDN data in 
SS7-enabled VoIP environments. Refer to the 

Release 12.2 and the 

, Release 12.2 for full 

command syntax and usage guidelines.

B

(data channel)

1 

S0:0

B

(data channel)

2

S0:1

B

(data channel)

3

S0:2

B

(data channel)

4

S0:3

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

B

(data channel)

21 

S0:20

B

(data channel)

22

S0:21

B

(data channel)

23

S0:22

D

(signaling channel)

24

S0:23

S6487

Channel

Type

Time Slot

Number

Logical
contents
of a PRI
interface

Virtual

Serial

Interface

Number