![](/images/new-backgrounds/1126638/12663817x1.webp)
Key ISAM voice features
Signaling protocols
Alcatel-Lucent ISAM Voice implements H.248/Megaco and SIP signaling to connect to NGN/IMS networks.
ISAM call control and traffic dimensioning with H.248/Megaco
Alcatel-Lucent ISAM Voice incorporates a separate call control engine that can be centralized for as many as 5,000 subscribers distributed in a number of access nodes (using either the Alcatel-Lucent 7302 ISAM, the 7330 ISAM FTTN Remote Aggregator or the 7356 ISAM FTTB Remote Expansion Module). The signaling gate- way, or NVPS, is not overloaded with payload processing as this is done in the line card itself. The NVPS handles signaling events only, and supports up to 10 call attempts per second.
Emergency calls with H.248/Megaco
Ten percent of the call capacity is always reserved for emergency use, in addition to the 512 active, regular calls handled by the NVPS with H.248. Because each line card has its own user agent, ISAM can always initiate an emer- gency call.
Voice traffic prioritization
The line card packetizes voice traffic into IP packets with the highest IP priority. These packets are delivered to the highest priority virtual local access network (VLAN) queue of the Alcatel-Lucent ISAM. For voice traffic, the strict priority queue assures minimum delay.
Alcate-Lucent ISAM Voice 9