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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
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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 • 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.