Dr. John P. Abraham Professor UTPA 24-IP V6 Dr. John P. Abraham Professor UTPA

Motivation If IP V4 works so well, why change? IP address exhaustion Accommodate for real-time audio and video with low jitter More complex addressing and routing capabilities including accommodation for mirrored (replicated) sites (pass the datagram to the nearest center). Sending packets to collaborators (group).

Why not v5 V5 was assigned to an experimental protocol known as ST.

Features of V6 Retained from v4 Changes Connectionless Maximum number of hps Most of the general facilities Changes Larger address space 128 bits. New datagram header – series of fixed length headers. Support for real time traffic by establishing a high-quality path through the underlying network. Extensible protocols – sender may add additional information to the datagram.

Datagram format Base header – extension headers from 1 to N – payload. Header: vers, traffic class, flow label, payload length, next header, hop limit, source address, destination address. The next header field is used to specify the type of inofrmation that follows the current header.

Purpose of multiple headers Economy V6 does not give fragmentation info, unless it is fragmented. Having separate headers makes it possible to define a large set of features. Avoiding unnecessary header fields can save space. Smaller datagrams takes less time to transmit. Extensibility Existing protocol headers can remain unchanged. A new next-header type is defined to allow for extensibility.