IPv6

Major goals 1.support billions of hosts, even with inefficient address space allocation. 2.reduce the size of the routing tables. 3.simplify the protocol, to allow routers to process the packets faster. 4.provide better security than current IP. 5.pay more attention to type of service, particularly for real time data. 6.aid multicasting by allowing scopes to be specified. 7.make it possible for a host to roam without changing its address. 8.allow the protocol to evolve in the future. 9.permit the old and new protocols to coexist for years.

Packet Format Important changes are –Extended address capacity –A streamlined 40 bytes header –Flow labeling and priority Fields –Version : 4 bits –Traffic class : 8 bits similar to TOS –Flow label: 20 bits –Payload length: 16 bits –Next header: 8 bits, like protocol –Hop limit: 8 bits, like TTL versionTra. classFlow label Payload lengthNext HdrHop limit Source address (128 bits) Destination address (128 bits) data Source address: 128 bits Destination address: 128 bits Data: payload

Following fields of IPv4 are not present in IPv6: –Fragmentation/reassembly –Checksum –Options

New ICMP IPv6 added new types of error mess –Packet Too Big –Unrecognized IPv6 options