READ Free Dumps For Cisco- 400-101
| Question ID 18543 | Refer to the exhibit.
Which action must you take to enable the WAN link to function properly?
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| Option A | Enter a clock rate on the DCE interface.
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| Option B | Enter a clock rate on the DTE interface.
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| Option C | Enter a compression algorithm on both interfaces.
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| Option D | Configure both interfaces for HDLC encapsulation.
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| Correct Answer | A |
Explanation Explanation: When connecting a serial cable to the serial interface of the router, clocking is provided by an external device, such as a CSU/DSU device. A CSU/DSU (Channel Service Unit/Data Service Unit) is a digital-interface device used to connect a router to a digital circuit. The router is the DTE (Data Terminal Equipment) and the external device is the DCE (Data Communications Equipment), where the DCE provides the clocking. However, in some cases we might connect two routers back-to-back using the routers serial interfaces (Example. Inside the router labs). Each router is a DTE by default. Since clocking is required to enable the interface, one of the two routers should function as DCE and should provide clocking. This can be done by using the "clock rate" command, from the interface configuration mode. Reference: http://www.omnisecu.com/cisco-certified-network-associate-ccna/how-to- configure-router-serial-interfaces.php
| Question ID 18544 | In which 802.1D port state are the root bridge, the root port, and the designated port(s) elected?
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| Option A | Listening
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| Option B | learning
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| Option C | forwarding
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| Option D | blocking
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| Option E | disabled
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| Correct Answer | A |
Explanation Explanation: STP switch port states: ✑ Blocking – A port that would cause a switching loop if it were active. No user data is sent or received over a blocking port, but it may go into forwarding mode if the other links in use fail and the spanning tree algorithm determines the port may transition to the forwarding state. BPDU data is still received in blocking state. Prevents the use of looped paths. ✑ Listening – The switch processes BPDUs and awaits possible new information that would cause it to return to the blocking state. It does not populate the MAC address table and it does not forward frames. In this state the root bridge, the root port, and the designated port(s) are elected. ✑ Learning – While the port does not yet forward frames it does learn source addresses from frames received and adds them to the filtering database (switching database). It populates the MAC Address table, but does not forward frames. ✑ Forwarding – A port receiving and sending data, normal operation. STP still monitors incoming BPDUs that would indicate it should return to the blocking state to prevent a loop. ✑ Disabled – Not strictly part of STP, a network administrator can manually disable a port. Reference: http://en.wikipedia.org/wiki/Spanning_Tree_Protocol