Basic TCP / IP
What does the term ARP mean?
Address Resolution Protocol, this is a broadcast message, everybody gets it. Only used on internal network.
What are the well know Port Numbers?
All numbers below 1024
How can a host tell the difference between TFTP & SMTP ?
By there different Port numbers. Note: This also allows data transfer using different protocols similtaneously, this is known as multiplexing.
Name 3 common UDP Ports?
DHCP - Dynamic Host Control Protocol - 67 & 68 TFTP - Trivial File Transfer Protocol - 69 SNMP - Simple Network Management Protocol - 161
Name the common TCP Ports?
FTP - File Transfer Protocol - 80 & 81 SSH - Secure Shell - 22 Telnet - 23 SMTP - Simple Mail Transfer Protocol - 25 HTTP - HyperText Transfer Protocol - 80 POP3 - Post Office Protocol 3 - 110 SSL - Secure Socket Layer - 443
What is the main advantage of UDP over TCP?
UDP's header is much smaller than TCP
Explain UDP and what does UDP stand for?
User Datagram Protocol 1. Connectionless 2. Best-effort delivery 3. Unreliable
Name a few well known TCP port numbers?
21 - FTP 22 - SSH 23 - TELNET 25 - SMTP 53 - DNS SERVER 80 - HTTP 110 - POP3 443 - HTTPS
What does the data link layer do?
It deals with MAC addresses. It is used so devices can communicate on the SAME local network, ie. where devices are connected to the same switch. MAC address do NOT communicate through routers
What does the transport layer do?
It has to make a choice between two protocols, either TCP or UDP
What is a "Socket"?
It is a combination of IP address and Port number. E.g. 10.1.1.1:69. This can also be expressed as IP address, Transport Portocol, Port Number E.g. 10.1.1.1,UDP,69
What is a MAC address function?
It is used so devices can communicate on the SAME local network, ie. where devices are connected to the same switch
What does the physical layer do?
It transmits electrical signals, cable etc.
What are the range of UDP Ports used for VoIP ?
16384 - 32767
Name the 3 things TCP and UDP headers have in common?
1. Source Port 2. Destination Port 3. Checksum
Name 4 TCP features?
1. Three way handshake 2. Windowing 3. Sequence numbering 4. Error detection and recovery
Name a few well known UDP port numbers?
53 - DNS CLIENT 69 - TFTP
What is a "Subnet Mask"?
A "Subnet Mask" dictates which portions of the IP address indentify the network and the host E.g. 255.255.255.0
What is the 2 address concept?
IP Address & MAC Address
What does the network layer do?
It deals with IP address. It allows devices to communicate end to end no matter how many routers are used
What are the 4 TCP/IP layers?
Transmission Control Protocol/Internet Protocol
Explain TCP and what does TCP stand for?
Transmission control protocol 1. Builds connections 2. Uses sequence numbers 3. Reliable (uses ACKS) 4. Session based
