192
SMG digital gateway
11
APPENDIX G: CONFIGURATION OF E1 CHANNELS TRANSIT THROUGH A SEMIPERMANENT
CONNECTION
Work principle
The channels for transit through a SIP interface are selected from E1 stream which is connected to SMG.
SMG transmit request via SIP interface for establishment of connections with remote SMG. Remote SMG
receives the request and connects voice tract with appropriate E1 channel. Then, all the voice data which comes
to the timeslot will be transmitted to the remote side (and from remote side to the active).
After establishment of connection SMG will control its status and tries to recover connection in case of a
failure. The connection integrity and availability of remote side is controlled by following means:
OPTIONS requests transmission;
session timers updating via RFC4028;
session activity control via RTCP;
control of presence of RTP-packets from remote side.
Objective
Configure connection between two geographically remote phones.
Initial conditions
Two remote objects connected through an Ethernet network;
On the first object the phone is connected through the subscriber line of Makom-MX multiplexer
and multiplexed to channel 1. The stream is connected to SMG via 0 E1 port;
IP address of SMG on the first object is 192.0.2.1;
On the second object the phone is connected through the subscriber line of Makom-MX
multiplexer and multiplexed to channel 4. The stream is connected to SMG via 1 E1 port;
IP address of SMG on the second object is 192.0.2.2.
Fig. 11 - Objects' connection scheme