Chapter 13 Voice Over IP (VoIP)
Page 13- 30 UNIVERGE NEAX 2000 IPS Request for Proposal (RFP) Reference Guide
Issue 6
Planning and Installation Vendor Support for Open System Standards
The vendor should be committed to supporting open system industry standards, such as
H.323, 802.1p and 802.1q, MGCP, TAPI, JTAPI, etc.
Voice Messaging:
A scalable and cost-effective voice messaging solution that supports industry standards such
as AMIS-A, VPIM, LDAP and IMAP.
Bandwidth requirements
One of the most important factors in the success of your IP network is to determine the
necessary network bandwidth needed for your application. Determining the appropriate
bandwidth is truly a function of two factors:
Number of Users (Phones)
Voice Compression for each user
Number of Users: The number of users is the number of simultaneous users (digital phones)
that will be required.
Voice Compression: NEC’s IP solutions deploy voice compression in order to extend multiple
users across fewer data channels. The following compression algorithms are supported:
G.711, G.723.1 and G.729A. Depending on the voice compression algorithm selected and the
number of voice frames encapsulated in one data packet.
Select the Proper Voice Compression: The best voice quality is achieved by using the non-
compression voice algorithm G.711. The maximum quality comes at the expense of the
highest utilized bandwidth. The largest vice compression is achieved by using G.729A. If you
are using this algorithm, you will save on bandwidth and still achieve voice quality that is
regarded as near toll. If absolute conversation quality is your focus and bandwidth is no
object, you probably want to select G.711. If bandwidth is a priority you will need to employ
G.729A.