Cisco router CSU/DSU configuration If your router is functioning as a CSU/DSU and you want to provide a 64,000 bps serial link, which command must you enter?
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ARouterA(config)#bandwidth 64
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BRouterA(config-if)#bandwidth 64000
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CRouterA(config-if)#clock rate 64
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DRouterA(config-if)#clock rate 64000
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ERouterA(config)#set speed 64k
Answer
Correct Answer: RouterA(config-if)#clock rate 64000
Explanation
Introduction / Context:When a Cisco router provides clocking on a serial connection (acting as a CSU/DSU), the clock rate command is required to set the data rate on the interface. This is typically used in lab environments or DCE (Data Communications Equipment) configurations.
Given Data / Assumptions:
- The router is providing DCE clocking.
- Speed required = 64,000 bps (64 kbps).
- Command must be entered in interface configuration mode.
Concept / Approach:
The clock rate command configures the DCE interface's clock speed. The value is entered in bits per second. For 64,000 bps, the correct command is clock rate 64000.
Step-by-Step Solution:
Enter global configuration mode.Enter the serial interface configuration mode.Type: clock rate 64000.Verify with: show controllers serial to confirm DCE role.Verification / Alternative check:
Cisco IOS reference guides confirm clock rate 64000 as the proper syntax for a 64 kbps link.
Why Other Options Are Wrong:
- bandwidth 64 or 64000: sets bandwidth metric, not actual clocking.
- clock rate 64: incorrect unit (bps vs kbps).
- set speed: not a valid Cisco IOS command.
Common Pitfalls:
- Confusing bandwidth (informational for routing protocols) with clock rate (actual line speed).
Final Answer:
RouterA(config-if)#clock rate 64000