Cisco Systems OL-8978-02 manual Cisco IP Phone, 55-2

Chapter 55 Configuring a VoIP Network

Understanding How a VoIP Network Works

Understanding How a VoIP Network Works

A telephony system built on an IP network instead of the traditional circuit-switched private branch exchange (PBX) network is called an IP PBX system. (See Figure 55-1.) The system’s components are described in these sections:

•Cisco IP Phone 7960, page 55-2

•Cisco CallManager, page 55-5

•Access Gateways, page 55-5

•How a Call Is Made, page 55-8

Figure 55-1 IP PBX System

Cisco CallManager

IP cloud

Analog Trunk Gateway

PSTN or PBX

PSTN or PBX

Voice Gateway 200

Analog stations (phone, fax, modem)

Digital Trunk Gateway (WS-X6608-T1/E1)

Analog Station Gateway

(WS-X6624-FXS)

10/100BASE-TX Module *

10/100BASE-TX Module (WS-X6348-RJ45V)

Catalyst 6500 series switches

WS-PWR-PNL

Analog stations (phone, fax, modem)

IP phone	PC
IP phone	PC

* Catalyst 4000, 5000, and 6000 10/100 modules

38202

Cisco IP Phone 7960

The Cisco IP Phone 7960 provides the connectivity to the IP PBX system. The IP phone has two RJ-45 jacks for connecting to the external devices: a LAN-to-phone jack and a PC-to-phone jack. The jacks use either Category 3 or Category 5 unshielded twisted-pair (UTP) cable. The LAN-to-phone jack is used to connect the phone to the LAN using a crossover cable; a workstation or a PC can be connected to the PC-to-phone jack using a straight-through cable.

The inline power is designed to work in cables from Category 3, Category 4, Category 5, and later up to 100 meters. The inline power works with IBM Token Ring STP cable of 100 meters when used with a Token Ring to Fast Ethernet adapter (LanTel Silver Bullet SB-LN/VIP-DATA adapter).

Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7

55-2 OL-8978-02