Week 5

Question 1

What do TCP/IP protocols do?

Answer 1

TCP/IP protocols add a header to data inherited from the layer above it

Question 2

What layer does TCP operate in?

Answer 2

Transmission Control Protocol (TCP) operates in the transport layer (Layer 4) of the OSI model.

Question 3

What are the three characteristics of TCP?

Answer 3

• Connection-oriented - ensures connection is established using three way handshake
• Sequencing and checksums - sends a checksum which is checked by host
• Flow control - gauges rate of transmission based on how quickly recipient can accept data

Question 4

What is a three-way handshake?

Answer 4

The TCP three-way handshake establishes a session before TCP transmits actual data. Three transmissions are sent before data transmission:
- Step 1 - A request for connection (SYN)
- Step 2 - A response to the request (SYN/ACK)
- Step 3 - A connection is established (ACK)

Question 5

What is UDP?

Answer 5

User Datagram Protocol (UDP) is an unreliable, connectionless protocol.
- No threeway handshake is performed
- Does not guarantee delivery of data
- No error checking, sequencing, or flow control
- Useful for live or audio or video transmissions

Question 6

What are the four fields in a UDP header?

Answer 6

• Source port
• Destination port
• Length
• Checksum

Question 7

What layer of the OSI model does IP operate at?

Answer 7

The network layer (Layer 3)

Question 8

What are the characteristics of IP?

Answer 8

• IP is an unreliable, connectionless protocol
• IP depends on TCP to ensure messages are put back together in the right order and to ensure each message reaches the correct application
• IP enables TCP/IP to interwork

Question 9

What is ICMP?

Answer 9

ICMP is a core network layer protocol that reports on the success or failure of data delivery. It only detects errors it does NOT correct them. ICMPv6 on IPv6 networks performs the functions of ICMP and ARP on IPv4 networks

Question 10

What can ICMP indicate?

Answer 10

ICMP can indicate the following:
- When part of a network is congested
- When data fails to reach its destination
- When data has been discarded because the allotted TTL has expired

Question 11

What is ARP?

Answer 11

Address Resolution Protocol (ARP) is a layer 2 (Data Link) protocol that works in conjunction with IPv4 to discover the MAC address of a host or node on the local network

Question 12

What is an ARP table?

Answer 12

An ARP table is the database of IP-to-MAC address mappings. It can contain two types of entries:
- Dynamic - created when client makes ARP request that could not be satisfied by data in the table
- Static - entries created manually

Question 13

What is NDP?

Answer 13

Neighbour Discovery Protocol (NDP) allows IPv6 devices learn about other devices on their networks. NDP (Neighbour Discovery Protocol) information carried in ICMPv6messages automatically detects neighbouring devices and automatically adjusts when nodes fail or are removed

Question 14

What do encryption protocols do?

Answer 14

Encryption protocols use cryptographic methods to scramble data into a format that can be read only by reversing the cipher

Question 15

What are the three benchmarks which encryption methods are evaluated?

Answer 15

• Confidentiality
• Integrity
• Availability

Question 16

What are the two categories of key encryption?

Answer 16

• Private key encryption
• Public key encryption

Question 17

What is IPsec?

Answer 17

IPsec (IP security) is an encryption protocol suite that defines rules for encryption, authentication, and key management for TCP/IP transmissions

Question 18

What are the five steps in IPsec?

Answer 18

1. IPsec initiation
2. Key management
3. Security negotiations
4. Data transfer
5. Termination

Question 19

What is SSL and TLS?

Answer 19

Both SSL and TLS are methods of encrypting TCP/IP transmissions. Both protocols work side by side and are widely known as SSL/TLS or TLS/SSL.

Question 20

What is an RAS and what are the two types?

Answer 20

A remote access server (RAS) allows for remote access. There are two different types of RAS:
- Dedicated devices
- Software running on a server