hw5-F23

d) State all the random access protocols and controlled access protocols. Explain why collision is an issue in random access protocols but not in controlled access protocols.

Computer Science   1.a) In a TCP communication, the receiver set the window size, rwnd=850. On the sender side, Sf=1077 and Sn=1115. The receiver sent an acknowledgement packet with ackNo=1097 and rwnd=830. What is the sliding window size on the sender’s end? Did the window open or close on the sender’s end and from which direction/s (e.g left and/or right direction/s)?       b)For the above scenario, the sender now sends 50 bytes and awaits an acknowledgment. What is the Sf and Sn now?

(ESP) Consider that we protect a TCP SYN packet using the ESP in the transport mode. A TCP SYN packet just comprises a TCP header which is 20 bytes (i.e., without TCP option). The IP packet header is also 20 bytes long (i.e., without IP option). Moreover, the block size for encryption is 256 bits (e.g., using AES-256), and the hash output’s size for message authentication is 512 bits (e.g., using SHA-1). What is the minimum amount of padding required?

#2.Answer T & F.

36. Figure below shows TCP communication between Alice and Bob. Alice Bob Seq = 1022, 28-bytes data A Seq = 250 bytes data C 1-byte data В Ack= Seq E Ack= 1000-bytes data Seq= Seq= F Ack=3001, 200 bytes data What is the sequence number (box F) of the third segment that Alice sends to Bob? a. 1049 b. 2001 c. 1300 d. 1299 е. 1050 -Timeout-

A frame containing http request is sent from Computer (A) [in whichever subnet it is now, make sure to show it in your figure], to the access point it is associated with. Draw the address fields (1, 2, and 3) of the frame travelling from Computer A to AP and the source and destination addresses of the frame travelling from AP to R1. The MAC addresses of AP1, AP2, and AP3 are M1, M2, and M3 respectively, and the Router R1’s MAC address connected to this Switch/AP is MRA. IP address values are already given, and the port addresses could also be used as given. The Router’s MAC address facing WAN side is MRW.

Can you name a few scenarios where SSH might be useful? Give a full list of and definitions for all SSH acronyms.

Computer Science

a) i) With respect to computer simulation, explain the terms: steady state, pseudo random number generator, stopping criteria. ii) A packet router receives packets at a rate of 1 million packets per second. The queue formation in the router is modelled as an M/M/1 queue. If the mean packet length is 1000 bytes, what is the output bitrate (in bps) needed (at the router) to ensure that the Pr(queue > 100 packets) ≤ 0.00001? iii) A Call Centre has no call waiting facility, and so loses blocked calls. What formula is used to evaluate call blocking probability? Use this formula, or a more convenient approximation, to find the call blocking probability if the applied traffic is 50 Erlangs and the number of servers is 50.

Electrical Engineering In the network given below, delays between the routers are given in milliseconds. a) Apply Bellman-Ford algorithm for the Router 1. In applying the algorithm, establish a table in which the maximum number of hops is started from zero and incremented by one for each iteration (h=0, 1, 2, 3, ...). In the table you will establish, include the label values consisting of minimum delay and path definition from Router 1 to other routers for each value of h. b) Briefly explain how the iteration ends. c) Indicate which labels will be stored in the routing table of Router I at the end of the algorithm. 2

2 This question is about Networks The following diagram shows a set of interconnected networks. The four networks (networks 1-4) are shown as labelled ellipses and the machines (A-K) con- nected to the networks represented as letters. Some machines (such às c, ánd E) are connected to multiple networks and are set to forward packets between the two networks. For the purposes of this guestions, machines will be addressed using the format 1.A where the number refers to the network the machine is connected and the let- ter identifies the machine. Machines connected to multiple networks can be ad- dressed usiņng multiple addresses - for example, machine c can be referred to as 1.cor 2.c depending on which network it is talking to. G Network 3 Network 1 -C Network 2 -F B D E Network 4 -K The network is configured to use next-hop routing. In the following questions, you are required to give the address of the next-hop where a machine should send a packet, if it is not on the same (local)…

32.  We have not given all the rules about the transition diagram and TCP states. To be complete, we should show the next state for any state with the arrival of any type of segment. TCP should know what action to take if any of the segment types arrive when it is in any of the states. What are some of these rules?

In Book computer networking a top-down approach sixth edition 4.4 (Network Address Translation (NAT)) I need to find ( NAT translation table) but for 6 address not for one  this is the Question: [ Consider the home network setup in Figure 3. Suppose each host of the3 hosts has two ongoing TCP connections, all to port 80 at host 118.1.40.86. Provide the sixcorresponding entries in the NAT translation table]

For NAT Network Address Translation Scenario: Jenny Bello is a small business owner selling and making customized computer peripherals. She has been finding it difficult to track her sales and inventories, however recently after an expert's advice, she adopted a Point of Sale (PoS) server. So, she can now track her sales and inventories at the store. However, she ran into another issue, the server can only be accessed within the store, because it has been assigned a private IPv4 address, it is not publicly accessible via the Internet. a) Why is not having the PoS server accessible over the Internet a problem for the business? b) What caused this problem? c) Propose a solution for the problem and explain how the solution works.

Consider that a 100 kbps data stream is to be transmitted on a telephone channel of BW=3.4 kHz and SNR=10 dB. Is the transmission free from ISI problem or not? Prove that. If it is not free, suggest and calculate the proper system modifications.

Do not give me incorrect solution. I will report .

Problem 5: Draw a Mealy FSM to model a LAN adapter. Serial data packets entering the FSM are analyzed. The start of a packet is indicated by the arrival of two consecutive 0's on the input line . The next three bits are the machine address. The targeted addresses are 100 or 110 where an output = 1 is generated. Any other addresses produce a zero at the output. A separate reset mechanism will put the machine in the initial state (i.e, you should never return to the initial state in your design).

SInternet Check sum Consider the figure below (simplex communication scenario). The TCP sender sends an initial window of 4 segments. Suppose the initial value of the sender ན༽)། sequence number, SEQ1, is 100 and the first 4 segments each contain 400 bytes of payload. As you can see ACK 3 is lost. What is the SEQ number (SEQ2, SEQ3, SEQ4, SEQ5) from the Sender and ACK Number (ACK1, ACK2, ACK3, ACK4, ACK5) from the receiver for each segment? Sender Seq1 Seq2 Seq3 Seg4 ACK1 ACK2 ACK3 ACK4 Seq5 ACK5 Receiver

Please solve it correctly and please provide explanation of your answers. Please answer parts g, h and i. A PC and a Web Server are communicating over a TCP connection. The PC had started the three way handshake with the initial sequence number of 3069 . The Web Server's initial sequence number is 4830 . The window size of the PC is 815 bytes and the window size of the Web Server is 463 bytes. Using the third TCP handshake ack segment the PC sends the http request of the size 396 bytes to the Web Server. Then the Web Server answers with 3 segments containing the requested data. The first segment size is 42 bytes and the second segment size is 276 bytes and the third segment size is 146 bytes respectively. The PC receives all three segments within the timer. But unfortunately the second segment was corrupted. So the PC immediately sends an acknowledgement segment. Assume that the PC uses Selective Repeat/Reject ARQ.   g) The second segment from webserver was corrupted. So the PC…

19. ARP is used for: O packet path determination O finding of a mapping IPV6 → MAC address O finding of a mapping IPV4 → MAC address O finding of a mapping IPV4 → TCP address

Find the odd man out. JNS, JL, JAL, BL a) JNS b) BL c) JAL d) JL

(a) If the second segment arrives before the first segment, in the ACK of the first arriving segment, what is the ACK number? (b) Draw and explain the 3-Way Handshake in TCP protocol.

81. A node X on a 10 Mbps network is regulated by a token bucket. The token bucket is filled at a rate of 2 Mbps. Token bucket is initially filled with 16 megabits. The maximum duration taken by X to transmit at full rate of 10 Mbps is ............ secs. a. 1 b. 2 c. 3 d. 4

Is that so, or not? Consider a TCP connection where the most recent SampleRTT was 1 second. It is recommended that the TimeoutInterval be set to more than one second.