Aastra Telecom 53I User Manual

Page of 818
Operational Features
5-144
41-001160-00, Release 2.1, Rev 04  
IP Phone Administrator Guide
Operational IP Phone Features
Bridged Line Appearance (BLA) (55i, 57i, 57i CT only)
A SIP bridge line appearance (BLA) on the IP phones allows multiple devices to 
share a single directory address (DA).
For example, people working at a technical support department could be located 
in different places. If their desktop phones are configured for BLA DA, when 
customer calls come in, all the phones with the BLA DA would ring but the call 
can only be answered by one of them. 
Once the call is answered, the rest of the phones reflect the status of the call. If the 
call was put on "hold" by the original recipient, any one from the group can pick 
up the call.
You can apply BLA on the IP phones as follows:
As a single BLA group - One BLA DA is shared among multiple phones. 
Only one phone at a time can pick up an incoming call or initiate an outgoing 
call on the BLA DA. All phones reflect the usage of the BLA DA. If the call is 
put on "hold", any one from the group can pick up the "held" call.
As a multiple BLA group - On one single phone, multiple BLA DA can be 
associated with different line appearances. Every BLA DA is independent 
from each other and follows the same rules as "a single BLA group".
As multiple instances of a BLA DA - A "x-line-id" parameter was defined in 
draft-anil-sipping-bla-02.txt
 to present the incoming call to or place an 
outgoing call on the specified line appearance instance. The parameter is 
carried in "Alert-Info" header field over the request-URI (INVITE e.g.) or in 
the NOTIFY messages to report the status of a dialog.
BLA DA can be configured on a global basis or on a per-line basis on the IP 
phones using the Aastra Web UI or the configuration files.
Notes: 
1. This feature is dependent on the IP telephony system to which the IP 
phone is registered and according to 
draft-anil-sipping-bla-02.txt.
2. Interactive Intelligence and Sylantro servers support the single BLA 
group with single line appearance feature only.