200 likes | 247 Views
Learn about IP addressing, classes, subnet masks, and delivery mechanisms. Explore how IP allows seamless communication while hiding physical network details. Understand the structure and fields of IP packets for efficient routing.
E N D
Internet Protocol Internetworking Lab I
Internet Protocol - IP • Internet • Collection of networks
Internet Protocol - IP • Internet • Collection of networks
Internet Protocol - IP • Mac Addresses are specific to Ethernet devices • Other technologies use different kinds of physical addresses • As a result, MAC addresses do not suffice for addressing on an internet • ALSO MAC addresses carry no information about the location of a device do not help in the routing of frames
Internet Protocol - IP • Goal • Single seamless communication system • HIDE details of the physical network • Required • Layer providing transparency from underlying • Network • Protocols • Forward packet from network to network • Addressing to recognize location of network
Internet Protocol - IP • Uniformity • Across technologies • Across different network topologies • To communicate across networks • without knowing hardware address • Solution • IP layer • IP addressing
IP Addresses 32 bits or 4 bytes dotted quad notation: 129.21.21.3 each number is in the range 0…255 each fits precisely into 1 byte (8 bits) Two parts network id and host id two “dimensions” help in routing packets on the network
Classes of IP Addresses Class A network id is 1st byte of the dotted quad host id is the remaining 3 bytes Class B network id is 1st two bytes host id is remaining two bytes Class C network id is 1st three bytes host id is remaining byte Classes D and E - special cases
IP Addresses The network mask (subnet mask) where there are 1’s indicates the network ID where there are 0’s indicates the host ID Examples for a class A address: 255.0.0.0 for a class B address: 255.255.0.0 for a class C address: 255.255.255.0
IP delivery • Unreliable - delivery not guaranteed • Connectionless -packet independence • Best Effort Delivery - only discard for a reason • Fragmentation
IP delivery • Unreliable - delivery not guaranteed • Connectionless -packet independence • Best Effort Delivery - only discard for a reason • Fragmentation
IP delivery • Version field - 4bits • the current version of IP is 4 (IPv4) • Hlen field - 4bits • specifies the length of the header • TOS (type of service) field - 8 bits • how packet should be handled • not widely used • Length field - 16 - measured in octets • specifies the length of the datagram
IP delivery • Identification • used to determine which fragments belong to each other • Flag • indicates how the fragmentation process will be handled • Fragment offset • indicates where a fragment belongs in the complete message
IP delivery • TTL (time to live) field • more of a hop count rather than a timer • Protocol field • identifies the higher-level protocol • Checksum field • checks an error in the header • Source and Destination addresses
IP delivery • TTL (time to live) field • more of a hop count rather than a timer • Protocol field • identifies the higher-level protocol • Checksum field • checks an error in the header • Source and Destination addresses