In class error detection and correction exercises 1) What would the parity bit be for each of the following (assume even parity): a. 1011000 b. 1110101 c. 1010011 d. 1011000 2) Calculate the two-dimensional parity check for the data transmitted in exercise #1. (Assume that all four data units in #1, along with their parity bits, are transmitted with a single two-dimensional parity check.) 3) Calculate the two-dimensional parity check for the following data. (Assume the two-dimensional parity check unit is 8 bits long. You will need to calculate the simple parity check bits as well as the parity check unit ): 101101011100000000111 4) Calculate the CRC for the data 110101001010 with the divisor 1010. What is the polynomial representation for the divisor? 5) Calculate the checksum for the data: 11101010, 01110001, 10010100. 6) Refer to Appendix A in the book to help you do the parts of this exercise. a. How would you render the word Networks into 7 bit ASCII characters? (Hint: Note the case of each letter.) b. Assuming even parity and that the parity bit trails the 7 bit ASCII characters in an 8-bit byte, how would you transmit the word Networks? c. Assuming that you are using two-dimensional parity checks, and that an even-parity parity byte follows every two data bytes, how would you transmit the word Networks? d. Assuming simple even parity and a checksum following every two data bytes, how would you transmit the word Networks?

1) Answer the following questions regarding the IP address 56.74.123.1. a) To what class does it belong? A b) What is its netID? 56 c) What is the network address for the network to which it belongs? 56.0.0.0 d) How many *useable* hosts can its network contain? (You may leave your answer in exponential notation.) e) What is the BINARY representation of the default mask associated with it? f) What is the SLASH notation of the default mask associated with it? /8 g) What would be the DECIMAL representation of its default mask? 255.0.0.0 2) Answer the following questions regarding the IP address 132.27.200.201. a) To what class does it belong? Class B b) What is its netID? 132.27 c) What is the network address for the network to which it belongs? 132.27.0.0 d) How many *useable* hosts can its network contain? (You may leave your answer in exponential notation.) e) What is the BINARY representation of the default mask associated with it? f) What is the SLASH notation of the default mask associated with it? /16 g) What would be the DECIMAL representation of its default mask? 255.255.0.0 3) Answer the following questions regarding the IP address 205.23.6.8.

a) To what class does it belong? b) What is its netID? 205.23.6 c) What is the network address for the network to which it belongs? 205.23.6.0 d) How many *useable* hosts can its network contain? (You may leave your answer in exponential notation.) e) What is the BINARY representation of the default mask associated with it? f) What is the SLASH notation of the default mask associated with it? g) What would be the DECIMAL representation of its default mask? 4) A host has an IP address of 98.128.5.6. a) What is the netID for the address? b) What is the hostID for the address? c) What is the network address?

1) What are the SLASH, BINARY, and DECIMAL representations of the subnet mask for each of the following addresses, assuming that four bits were borrowed to form subnets? What is the address of the subnetwork to which each belongs? What is the hostID for each device? a) 56.74.123.1. b) 132.27.200.201. c) 205.23.6.8. 2) A host has an IP address of 98.128.5.6. The subnet mask is /10. a) What is the binary representation of the subnet mask? b) What is the decimal representation of the subnet mask? c) What is the subnetwork address? d) What is the broadcast address for the subnetwork? e) What is the range of useable IP addresses for the subnet?

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3) A router contains the following routing table.

Mask

Destination Address

Next-hop address

Interface

/16

48.2.0.0

108.3.4.6

S2

/8

64.0.0.0

150.0.0.23

E0

/20

103.92.160.0 94.0.0.13

S1

/32

203.32.45.6

98.4.5.7

E1

/0

/0

204.204.1.3 S0

A) Out of which port does it send a packet which contains each of the following as the destination address? a) 48.2.3.4 b) 68.3.5.6 c) 103.92.168.3 d) 103.92.200.3 B) What is the next-hop address for the host-specific route in the routing table above?

C) What is the next-hop address for the default route in the routing table above?