Content

| 7.6 |  | Network Design Issues for Voice |
| 7.6.1 |  | IP Phone physical connectivity |

Cisco IP Phones, which connect to a switch port, also provide connectivity for an attached computer. The phone electronics, which include a three-port switch, preserve the switched connectivity model for the computer and ensure quality of service for both the IP phone and the downstream computer.

Several options exist for physically connecting the IP phone to the network. The first option is to connect the IP phone to the switch and to connect the data device (computer or workstation) to the switched Ethernet port on the IP phone. This is the most common connectivity option and aids in rapid deployment with minimal modifications to the existing environment. This arrangement has the advantage of using a single port on the switch to provide connectivity to both devices. Also, no changes to the cabling plant are required if the phone is line powered.

The second option is to connect the IP phone and the computer using different switch ports. Although this option doubles the switch port count for every user, it provides a level of redundancy for the user. If the phone goes down, the PC is not affected, and vice versa. Also, the phone and PC to ports can be connected on different modules, thus achieving another layer of redundancy by providing protection for one of the devices if either module goes down.

The third option differs from the others in that the phone is not a hardware device, but is a JTAPI application running on a computer. This option, the Cisco IP SoftPhone, could be particularly useful in environments where the need for a separate handset is minimal.