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See IP Address for basic understanding
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IPv4
- Network ID
- Common to all computers on a network
- Host ID
- Unique ID of a particular computer on a network
- How many bits for each?
- Depends on subnetting, which gives different classes of IP address
- 32 bit binary number which acts like a filter when it is applied to the 32 bit IP address
- By comparing a subnet mask with an IP address, systems can determine which portion of the IP address relates to the network and which portion relates to the host
- Depends on subnetting, which gives different classes of IP address
- Network ID
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IPv6
Internet Protocol (Datagram)
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The Internet Protocol is what provides the IP address
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IP is a routable protocol (meaning it can be sent across networks) that handles addressing, routing, and the process of putting data into or taking data out of packets
- It is described as connectionless because it doesn’t establish a connection with a remote computer before sending data
- Packets sent via connectionless methods are known as datagrams
- It is described as connectionless because it doesn’t establish a connection with a remote computer before sending data
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An IP packet can be lost, delayed, duplicated or delivered out of sequence, but IP makes no attempt to recover from these errors
- Recovery is the responsibility of higher layer protocols including Transport layer protocols such as TCP
- Royal Mail does not catalogue every piece of post. Mail enters the system and the send/recipient need to worry about arrival
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IP datagram headers contain
- Source IP address
- The IP address of the source of the datagram
- Destination IP address
- The IP address of the destination of the datagram
- Protocol
- Indicates which protocol the receiving IP should pass the packets to. e.g. TCP, UDP, ICMP, etc.
- Checksum
- An error control method that performs a calculation to verify the integrity of the IP header
- Time-to-Live (TTL)
- Specifies the number of networks the datagram can travel before it is discarded and prevents datagrams from circling endlessly on the network
- Total Length
- The length of the IP datagram including the header
- Source IP address