Implementing and Operating Cisco Enterprise Network Core Technologies (ENCOR) v1.2InfrastructureMedium
A network engineer is configuring a Cisco router to use NTP. The router needs to synchronize its time with a reliable external source, but also provide time synchronization services to other devices on its local network segment. Which NTP mode should be configured on the router's interface connected to the local network?
- AServer
- BSymmetric Active
- CBroadcast
- DClient
Show answer & explanationAnswer & explanation
Correct answer: B. Symmetric Active
Symmetric Active mode allows a router to act as both an NTP client (synchronizing with an upstream server) and an NTP server (providing time to downstream clients). It also enables peer-to-peer relationships for high accuracy, satisfying the dual requirement.
Why the other options are wrong
- A. Server mode only provides time, it does not synchronize with an upstream source unless configured as a client as well.
- C. Broadcast mode sends time updates without requiring requests, but it's less accurate and doesn't handle upstream synchronization.
- D. Client mode only requests time synchronization; it does not provide time to others.
NTP Symmetric Active Mode
An NTP mode where a device can both act as a client to synchronize its own time and as a server to provide time to other devices, often used for peer-to-peer synchronization.
- Router can be both client and server.
- Establishes a peer relationship.
- Provides high accuracy for time synchronization.
Memory trick: Symmetric Active: Give and take, a two-way street for time.