Advanced Computer Networks: Lecture 26 - Dr. Amir Qayyum

Advanced Computer Networks: Lecture 26. This lecture will cover the following: basics of internetworking (heterogeneity); IPv6 wish list/planned support; IPv6 addresses; IPv4 packet format review; IPv6 packet format; IPv6 extension headers; IPv6 design controversies;...

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CS716 Advanced Computer Networks

By Dr. Amir Qayyum

2Lecture No. 26

• Many suggestions, merged in time to several options

• IETF selected Simple Internet Protocol Plus (SIPP with some modifications, dubbed it version 6

with many hosts

010

Version HLen TOS Length

TTL Protocol Checksum

SourceAddr DestinationAddr Options (variable) (variable)Pad

Data

IPv6 Packet Format

destination address word 4 destination address word 3 destination address word 2 destination address word 1 source address word 4 source address word 3 source address word 2 source address word 1 payload length next header hop limit version priority flow label

next header 0 no.of.address

es next addressstrict/loose routing bitmap

1 – 24 addresses

• Larger fragment identification field

next header reserved offset resv M

identification

– All headers and data after ESP are encrypted

• Source to backbone

• Across backbone

• Backbone to destination

– Inconveniences interactive users

• Lighter, so you go faster

• Unprepared for the unexpected

• No

– Typically duplicated in data link and transport layers– Major expense in IPv4 routers

– In case of IPv6, it is mandatory in UDP and TCP

• No clearly superior design proposal

• Too clunky to turn off

• How ?

– Political export/import issues

– Cryptographic strength issues