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Lab 3-3: Phone Boot/Registration Process

The most important part of solving problems with VoIP solutions is knowing how a properly functioning system should work and comparing it to an existing problem. Cisco IP Phones have multiple steps to complete when connected to the network, and understanding the process from booting to registration will speed resolution of problems.

Q&A

1. List at least three ways that a Cisco IP Phone can receive power.

  • Cisco Catalyst Switch PoE (Cisco prestandard or 802.3af power)
  • Power Patch Pannel PoE (Cisco prestandard or 802.3af power)
  • Cisco IP Phone Power Brick (wall power)

2. What two protocols can Cisco IP Phones use to register to the Call Agent (depending on the phone firmware loaded)?

  • Skinny Client Control Protocol (SCCP)
  • Session Initiation Protocol (SIP)

3. Number the following steps in the order the occur during the phone boot process:

  1. The phone receives power, which might involve receiving PoE from the switch.
  2. The phone learns the VLAN information from CDP.
  3. The phone gets IP address information from DHCP, including option 150.
  4. The phone downloads the configuration file from the TFTP server.
  5. The phone registers with one or more Call Agents.
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