READ Free Dumps For Cisco- 400-101
| Question ID 18485 | Which statement is true regarding the UDP checksum?
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| Option A | It is used for congestion control.
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| Option B | It cannot be all zeros.
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| Option C | It is used by some Internet worms to hide their propagation.
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| Option D | It is computed based on the IP pseudo-header.
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| Correct Answer | D |
Explanation Explanation: The method used to compute the checksum is defined in RFC 768: Checksum is the 16-bit one's complement of the one's complement sum of a pseudo header of information from the IP header, the UDP header, and the data, padded with zero octets at the end (if necessary) to make a multiple of two octets. In other words, all 16-bit words are summed using one's complement arithmetic. Add the 16-bit values up. Each time a carry-out (17th bit) is produced, swing that bit around and add it back into the least significant bit. The sum is then one's complemented to yield the value of the UDP checksum field. If the checksum calculation results in the value zero (all 16 bits 0) it should be sent as the one's complement (all 1s). Reference: http://en.wikipedia.org/wiki/User_Datagram_Protocol
| Question ID 18486 | Refer to the exhibit.
Your network is suffering excessive output drops. Which two actions can you take to
resolve the problem? (Choose two.)
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| Option A | Install a switch with larger buffers.
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| Option B | Configure a different queue set.
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| Option C | Reconfigure the switch buffers.
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| Option D | Configure the server application to use TCP.
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| Option E | Update the server operating system.
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| Correct Answer | A,B |
Explanation Explanation: Installing a switch with larger buffers and correctly configuring the buffers can solve output queue problems. For each queue we need to configure the assigned buffers. The buffer is like the storage space for the interface and we have to divide it among the different queues. This is how to do it: mls qos queue-set output
buffers Q1 Q2 Q3 Q4 In this example, there is nothing hitting queue 2 or queue 3 so they are not being utilized.