Instruction manual

Internet Protocol (IP)

Issue 4 May 2003 127555-233-767

See ‘‘T1’’ on page 136.

Internet Protocol (IP)

IP trunks

IP trunk groups may be defined as a virtual private network’s tie lines between

systems or ITS-E servers running Communication Manager. Each IP trunk circuit

pack provides a basic 12-port package that can be expanded up to a total of

30 ports. The number of ports that are defined will correspond to the total number

of simultaneous calls transmitted over the IP trunk interface.

The benefits of IP trunk include a reduction in long distance voice and fax

expenses, facilitating global communications, providing a full function network

with data and voice convergence and optimizing networks by using the available

network resources.

IP trunking is a good choice for basic, corporate voice and fax communications,

where cost is a major concern. IP trunk calls travel over a company’s intranet

rather than the public telephone network. So, for the most common types of

internal corporate communications, IP trunks offer considerable savings.

IP trunking is usually not a good choice for applications where calls have to be

routed to multiple destinations (as in most conferencing applications) or to a voice

messaging system. IP trunk calls are compressed to save network bandwidth.

Repeated compression and decompression results in a loss of data at each stage

and degrades the final quality of the signal.

The maximum number of compression cycles acceptable on a call is three, and

three compression cycles can compromise voice quality. Normal corporate voice

or fax calls typically go through fewer than three compression cycles. However,

multipoint conference calls and most voice messaging systems add too many

compression cycles for acceptable quality.

H.323 trunk

A TN802B in MedPro mode or a TN2302AP IP interface enables H.323 trunk

service using IP connectivity between two systems running Communication

Manager. The H.323 trunk groups can be configured as system-specific tie trunks,

generic tie trunks, or direct-inward-dial (DID) public trunks. In addition, the

H.323 trunks support ISDN features such as QSIG and BSR.