Table of Contents
Advertisement
LANCOM 1722 VoIP – LANCOM 1724 VoIP
Chapter 1: Introduction
Depending on the application at hand, both the called and the calling num-
bers have to be modified so that a return call can be made to the source
number.
Call number translation at the transition to outside lines is primarily imple-
mented by mapping entries in the ISDN and SIP lines and by rules in the call-
routing table.
1.5.4
The Call Manager
The Call Manager has the central task of allocating the calls waiting to be
switched to a certain line or to a certain user. The Call Manager makes this
allocation by using the call-routing table and the list of registered users. The
calls are switched in the following steps:
28
¿
»
·
³
Processing of called numbers (Calling Party ID)
First of all there is a check to see whether a numeric or alphanumeric
number is available. Typical dialing separators such as "()-/" and <blank>
are removed. A leading "+" is left in place. In this case, the number is still
treated as a numeric number. If the check reveals any other alphanumer-
ical character, the number is treated as alphanumeric and remains
unchanged.
Resolution of the call in the call-routing table
After processing the Called Party ID, the call is passed over to the call-
routing table. Entries in the call-routing table consist of sets of conditions
and instructions. The entries—with the exception of the default routes—
are searched through and the first one that satisfies all of the conditions
is executed.
Resolution of the call with tables of local subscribers
Mapping the destination telephone number
³
external MSN from the ISDN network
·
internal telephone number of the ISDN
user
Mapping the source telephone number
»
internal telephone number of the SIP
user
¿
external SIP telephone number in the
SIP provider's network
Advertisement
Table of Contents
