Citel EXTender PBXgateway II Supplementary Manual

CITEL'S POSITIONING FOR xDSL AND CABLE MODEM
NETWORKS
Citel manufactures the EXTender™ family of distributed voice solutions that work over serial and
packet networks. Many of these solutions are designed to work using Internet Protocol (IP), but require
a "managed" network connection that guarantees bandwidth, reduces latency on the network and
assures timely delivery of packets across the wide area network (WAN). Absent a "managed" network
connection, voice quality and service may be compromised. The Internet uses IP as a protocol, but
does not have built-in management features to eliminate the latency issues that often interfere with
business quality voice.
Citel recommends its solutions to run over managed IP connections for best results. A "managed"
connection means a network where end-to-end jitter, latency and packet loss can be monitored and
acceptable parameters can be set. Citel supports all of its products with a full range of services,
including installation, support, time and materials repair and advance replacement.

Citel Products

EXTender™ 4000 for IP
EXTender™ 6000 for Branch Offices
EXTender™ 7000 for Branch Offices
EXTender PBXgateway™
EXTender PBXgateway II™
For the purposes of this document, we will confine our discussion to the EXTender 4000 for IP, a
single-user client for home offices and teleworkers. As this is the product most often associated with
home office usage, many customers ask if an existing xDSL or Cable modem connection to the Internet
could serve as the network. The general discussion, however, applies to all the other IP-compatible
Citel solutions.
Citel Technologies. markets and supports solutions that utilize Internet Protocol as a transport
mechanism. CItel recommends running its solutions over managed IP network connections, where
jitter, latency and packet loss, can be monitored and controlled.
This is due to the Internet's inherent lack of management and inability to guarantee Quality of Service
(QoS) across the network.
This situation is not unique to Citel, but applies to all voice solutions that work over
Internet Protocol (IP) networks. The problem arises from the confusion between the
Internet, which is a network, and IP, which is a transmission standard.
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