Computer Networks Exam 2025
Questions and Answers
Broadcast routing - ✔✔network layer provides a service of delivering a packet sent from
a source node to all other nodes in the network
Multicast routing - ✔✔enables a single source node to send a copy of a packet to a subset
of other network nodes
What is a broad definition for the network layer? - ✔✔the network layer
transports segments from a sending node to a receiving node (hosts)
What are some services that network layer provides to a flow of packets? - ✔✔In-
order delivery, guaranteed minimum bandwidth to flow, restrictions on changes in inter-
packet spacing
What three things does a virtual circuit network consist of? - ✔✔Path from source
to destination
VC numbers (one number for each link along path)
Entries in forwarding tables in routers along path
What do VC routers maintain? - ✔✔connection state information
, Briefly describe datagram network. - ✔✔No call setup at network layer, packets
forwarded using destination host address, no network-level concept of "connection"
How are datagram forwarding tables set up? (Mention longest prefix matching) -
✔✔They feature a range of destination addresses for each link interface. Longest prefix
matching: use longest address prefix that matches the destination address.
Is the Internet datagram or VC? Is ATM datagram or VC? - ✔✔Internet = datagram
(data exchange among computers, many link types, "smart" end systems)
ATM = VC (evolved from telephony, human conversation, "dumb" end systems, like telephones)
What does a class A IP address consist of? - ✔✔network | host
1.0.0.0 to 127.255.255.255
What does a class B IP address consist of? - ✔✔10 | network | host
128.0.0.0 to 191.255.255.255
What does a class C IP address consist of? - ✔✔110 | network | host
192.0.0.0 to 223.255.255.255
What does a class D IP address consist of? - ✔✔1110 | multicast address
224.0.0.0 to 239.255.255.255
How does an ISP get its IP addresses? How does a customer network get its IP addresses?
How does a host get its IP addresses? - ✔✔From IANA (Internet Assigned Numbers
Authority)
From its ISP
Questions and Answers
Broadcast routing - ✔✔network layer provides a service of delivering a packet sent from
a source node to all other nodes in the network
Multicast routing - ✔✔enables a single source node to send a copy of a packet to a subset
of other network nodes
What is a broad definition for the network layer? - ✔✔the network layer
transports segments from a sending node to a receiving node (hosts)
What are some services that network layer provides to a flow of packets? - ✔✔In-
order delivery, guaranteed minimum bandwidth to flow, restrictions on changes in inter-
packet spacing
What three things does a virtual circuit network consist of? - ✔✔Path from source
to destination
VC numbers (one number for each link along path)
Entries in forwarding tables in routers along path
What do VC routers maintain? - ✔✔connection state information
, Briefly describe datagram network. - ✔✔No call setup at network layer, packets
forwarded using destination host address, no network-level concept of "connection"
How are datagram forwarding tables set up? (Mention longest prefix matching) -
✔✔They feature a range of destination addresses for each link interface. Longest prefix
matching: use longest address prefix that matches the destination address.
Is the Internet datagram or VC? Is ATM datagram or VC? - ✔✔Internet = datagram
(data exchange among computers, many link types, "smart" end systems)
ATM = VC (evolved from telephony, human conversation, "dumb" end systems, like telephones)
What does a class A IP address consist of? - ✔✔network | host
1.0.0.0 to 127.255.255.255
What does a class B IP address consist of? - ✔✔10 | network | host
128.0.0.0 to 191.255.255.255
What does a class C IP address consist of? - ✔✔110 | network | host
192.0.0.0 to 223.255.255.255
What does a class D IP address consist of? - ✔✔1110 | multicast address
224.0.0.0 to 239.255.255.255
How does an ISP get its IP addresses? How does a customer network get its IP addresses?
How does a host get its IP addresses? - ✔✔From IANA (Internet Assigned Numbers
Authority)
From its ISP
