Implementing and Operating Cisco Enterprise Network Core Technologies (ENCOR) v1.2InfrastructureMedium
A network engineer is configuring a Cisco Catalyst 9300 switch and needs to ensure that all directly connected Cisco IP phones receive their configuration and firmware updates from a specific TFTP server. The engineer wants the switch to automatically provide the TFTP server IP address and other voice-related parameters to the phones upon connection. Which feature should be configured on the switch?
- AIP Helper Address
- BCDP with LLDP-MED
- CVoice VLAN with DHCP Option 150
- DDHCP Relay
Show answer & explanationAnswer & explanation
Correct answer: C. Voice VLAN with DHCP Option 150
Configuring a Voice VLAN with DHCP Option 150 allows the switch to inform IP phones about the TFTP server's IP address. When an IP phone connects, the switch places it into the voice VLAN, and the DHCP server configured for that VLAN provides the necessary voice-specific options, including Option 150 for the TFTP server.
Why the other options are wrong
- A. IP Helper Address is synonymous with DHCP Relay, forwarding broadcast requests.
- B. CDP/LLDP-MED discover device capabilities, but don't automatically configure phones with TFTP server details.
- D. DHCP Relay forwards DHCP requests to a DHCP server, but doesn't specifically provide TFTP server info for phones.
Voice VLAN with DHCP Option 150
A configuration where a switch automatically assigns IP phones to a dedicated VLAN (Voice VLAN) and provides them with the IP address of a TFTP server via DHCP Option 150.
- Separates voice traffic from data traffic for QoS and security.
- DHCP Option 150 is specifically used by Cisco IP phones to find their TFTP server.
- Simplifies IP phone deployment by automating configuration.
Memory trick: Phones Find Home: VLAN, DHCP, TFTP.