"communication skill (DOC)"
ATM Networks CSE 884 Homework 1 20 marks 1. Why do ATM networks use cell switching? 2. Why is virtual circuit switching critical for ATM networks? (Please list three reasons ) 3. What are the "adaptation layers"? Are they in the switches? Are they in the end-hosts? 4. Is it practical to build a large (i.e., with lots of ports) input buffered ATM switch with fast links? Why or why not? 5. Is it practical to build a large (i.e., with lots of ports} outputbuffered ATM switch with fast links? Why or why not? 6. How many low-bit-rate calls can be supported by AAL2 in a single ATM connection? 7. Estimate the bit rate of the connection if an AAL2 carries the maximum number of calls carrying voice at 12 kbps. 8. Compare the overhead of AAL3/4 with that of AAL5 for a 64Kbyte packet. 9. Explain how the three-bit sequence number in the AAL1 header can be used to deal with lost cells and with miss inserted cells. 10. Suppose that an ATM connection carries voice over AAL-1. Suppose that the packetization delay is to be kept below 10 ms.Calculate the percentage of overhead if the voice is encoded using PCM. 11. Explain how the header error checksum can be used to synchronize to the boundary of a sequence of contiguous ATM cells. What is the probability that an arbitrary five-odd block will satisfy the header error checksum? Assume bits are equally likely to be 0 or 1. What is the probability that two random five-octet blocks that correspond to two consecutive headers pass the error check?