Week 5 Flashcards
What do TCP/IP protocols do?
TCP/IP protocols add a header to data inherited from the layer above it
What layer does TCP operate in?
Transmission Control Protocol (TCP) operates in the transport layer (Layer 4) of the OSI model.
What are the three characteristics of TCP?
- 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
What is a three-way handshake?
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)
What is UDP?
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
What are the four fields in a UDP header?
- Source port
- Destination port
- Length
- Checksum
What layer of the OSI model does IP operate at?
The network layer (Layer 3)
What are the characteristics of IP?
- 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
What is ICMP?
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
What can ICMP indicate?
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
What is ARP?
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
What is an ARP table?
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
What is NDP?
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
What do encryption protocols do?
Encryption protocols use cryptographic methods to scramble data into a format that can be read only by reversing the cipher
What are the three benchmarks which encryption methods are evaluated?
- Confidentiality
- Integrity
- Availability