Implementing and Operating Cisco Enterprise Network Core Technologies (ENCOR) v1.2InfrastructureMedium
A network engineer is implementing a new DHCP server on a Cisco router for a segment of the network where VoIP phones are also present. The phones require specific DHCP options to register with the call manager. Which DHCP option is commonly used to provide the IP address of the TFTP server (Call Manager) to Cisco IP phones?
- AOption 66
- BOption 150
- COption 43
- DOption 125
Show answer & explanationAnswer & explanation
Correct answer: B. Option 150
Cisco IP phones specifically use DHCP Option 150 to discover the IP address of the TFTP server, which in Cisco VoIP environments is typically the Cisco Unified Communications Manager (CUCM) or a dedicated TFTP server responsible for providing phone configurations.
Why the other options are wrong
- A. Option 66 is for TFTP server name, not typically the IP address for Cisco phones.
- C. Option 43 is a vendor-specific option used for various purposes, but not specifically for TFTP server IP for Cisco phones.
- D. Option 125 is a vendor-specific option for enterprise-specific information, not generally for TFTP server IP for Cisco phones.
DHCP Option 150 (TFTP Server)
A DHCP option specifically used by Cisco IP phones to obtain the IP address of the TFTP server from which they download configuration files and firmware.
- Crucial for Cisco IP phone registration.
- Points to the Cisco Unified Communications Manager (CUCM) or a dedicated TFTP server.
- Ensures phones receive necessary configuration for operation.
Memory trick: 150 for TFTP Phone Setup