Class A
First byte: 1-126
Network.host.host.host
Default subnet mask: 255.0.0.0
Class B
First byte: 128-191
Network.network.host.host
Default subnet mask: 255.255.0.0
Class C
First byte: 192-223
Network.network.network.host
Default subnet mask: 255.255.255.0
Port
Each application layer software has a unique port address. It’s used to link to the application layer
Port 80
Http
Port 443
Https
Port 21
FTP
Port 25
SMPT
Quality of Service (QoS)
A special type of connection-oriented messaging in which different connections are assigned different priorities.
Different classes of service are defined, each with different priorities
Unicast
One computer to another computer
Broadcast
One computer to all computers in the network (what you will see in wireshark)
Multicast
One computer to a group of computers (ex. Videoconferencing)
Routing Information Protocol (RIP)
-Dynamic distance vector protocol used for interior routing
- Operation:
- Network manager builds the touting table
- Routing tables broadcast periodically(every minute or so)
- When new computers are added, router counts “hops” and selects the shortest route
- useful in smaller, less complex networks
Open Shortest Path First (OSPF)
- Dynamic link state protocol used for interior routing
- most widely used interior routing protocol on large enterprise networks
- more reliable paths
- less burdensome to the network because only updates sent
Dynamic Host Configuration Protocol (DHCP)
- most common protocol for dynamic addressing
- device sends out a broadcast message
- DHCP responds with IP settings
- addresses are “leased for a length of time
When the computer is turned on and connects to the network, it first issues a broadcast DHCP message that is directed to any DHCP server that can “hear” the message. This message asks the server to assign the requesting computer a unique network layer address. The server runs a corresponding DHCP software package that responds to these requests and sends a message back to the client, giving it its network layer address
Domain Name Service (DNS)
Translates application layer address into network layer address.
Www.indiana.edu———>129.79.78.193
Address Resolution Protocol (ARP)
Identifies MAC address of the next device in the circuit
Translates network layer to data link layer
