Network

Question 1

What is the name given to service models transporting datagrams in the Network Layer and why is it rarely used?

Answer 1

Best Effort models, rarely used because it i not reliable. TCP is built on top to allow this.

Question 2

What’s the best effort service for the Network layer nowadays?

Answer 2

IP(Internet Protocol)

Question 3

What is a Virtual Circuit?

Answer 3

Source to destination path, behaves similar to telephone circuit. 
Consists of 
- Path
- VC numbers
- Entries in forwarding tables

Question 4

What is the longest prefix matching algorithm?

Answer 4

Looks for the forwarding table entry for a given destination address.

Question 5

Name 3 main network layer functions

Answer 5

1 Routing protocols
2 IP protocols
3 ICMP protocols

Question 6

Must all interfaces be given an IP address?

Answer 6

Yes

Question 7

Whats an interface?

Answer 7

Connection between host/router and physical link

Question 8

What is a subnet?

Answer 8

A logical subdivision of an IP network

Question 9

What is a VLSM?

Answer 9

Variable Length Subnet Masking allows you to divide an IP address space into a hierarchy of subnets without wasting large numbers of addresses.

Question 10

What is a CIDR?

Answer 10

Classless Inter-Domain Routing is a way to allow more flexible allocation of IP addresses.

Question 11

Name 2 ways to get an IP address

Answer 11

1- Hard coding

2- DHCP

Question 12

What is DHCP?

Answer 12

Dynamic Host Configuration Protocol dynamically assigns IP addresses to hosts.

Question 13

List the four phases of DHCP messaging and who it comes from

Answer 13

host: “DHCP discover”
DHCP server: “DHCP offer”
host: “DHCP request”
DHCP server: “DHCP ack”

Question 14

What is IP fragmentation?

Answer 14

This is when IP datagram’s are divided into smaller datagrams in order to satisfy the MTU(maximum transfer unit) and then reassembled at the final destination.

Question 15

Name the 3 switching(forwarding) fabrics

Answer 15

1 Bus
2 Memory
3 Crossbar

Question 16

Name the 3 Router input port functions

Answer 16

1 Bit level reception
2 Data link layer
3 Queueing

Question 17

What is NAT?

Answer 17

Network Address Translation is the process of assigning a public address to a computer(s) in a private network.

Question 18

What is the NAT traversal problem?

Answer 18

This is when the client wants to connect to the server with a private address but the public address is the only one visible.

Question 19

Name 3 solutions to the NAT traversal problem

Answer 19

A- Configure NAT to forward incoming connection requests at a given port to the server
B- Universal Plug and Play
C- Relaying(creating a bridge for connection)

Question 20

What is Internet Control Message Protocol (ICMP)?

Answer 20

Used by hosts and routers to communicate network-level information

Question 21

What’s IPv6?

Answer 21

The most recent version of IP that enables data communications over a packet switched network.

Question 22

Name two methods of coping with the transition from IPv4 to IPv6

Answer 22

• Dual Stack

- Tunneling

Question 23

What type of routing algorithm will global and decentralized networks use?

Answer 23

Global- Link state algorithms

Decentralized- Distance vector algorithms

Question 24

What does autonomous systems mean?

Answer 24

To aggregate routers into regions running the same protocol

Question 25

What is broadcast routing?

Answer 25

Delivering packets from source to all other nodes.

Question 26

What is flooding?

Answer 26

When nodes receives broadcast packet, sends copy to all neighbors