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Telecommunications Networking II
Topic 23
Emerging Protocols
Ref: Tanenbaum pp 437-446
Dr. Stewart D. Personick
Drexel University
Copyright 2002, S.D. Personick. All Rights Reserved.
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Emerging Protocols: IPv6
• The current version of the IP (layer 3)
protocol is IPv4:
-address space is limited by the use of 4-byte
addresses, and by the way those addresses
are assigned
-lacks security functionality
-inadequate flexibility to support new and
differentiated network layer services
Copyright 2002, S.D. Personick. All Rights Reserved.
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Emerging Protocols: IPv6
• IPv6 provides:
-16 byte addresses (3.4 x 10 **38 possible
addresses!!!)
-Header simplification: 7 fields plus options
vs. 13 for IPv4
-Better support for options; simplifies the job
of routers
-Authentication and privacy features
-Better support for differentiated “types of
services”
Copyright 2002, S.D. Personick. All Rights Reserved.
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IPv6 Header
Version Priority
Flow label
Payload Length
Next Header
Hop limit
Source address: 16 bytes
Destination Address: 16 bytes
Copyright 2002, S.D. Personick. All Rights Reserved.
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IPv6 Header
• Version: always 6 for IPv6 and 4 for IPv4
• Priority field: distinguishes between packets
that can be buffered/delayed vs. packets that
must either be sent immediately or discarded
(and in-between cases)
• Flow label: allows source-destination pairs to
set up the equivalent of virtual circuits with
may (for example) have defined quality-ofservice specifications
Copyright 2002, S.D. Personick. All Rights Reserved.
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IPv6 Header
• Payload length: tells how many bytes follow
the 40-byte header
• Next header: tells which (optional) “extension
header” type (if any) follows this header. If
this is the last header, indicates which
transport protocol (TCP, UDP…) to pass this
packet to
• Hop counter: decremented on each hop
Copyright 2002, S.D. Personick. All Rights Reserved.
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IPv6 Extension Header Types
• Hop-by-hop options extension header:
miscellaneous information that every router
must pay attention to; for example:
- “jumbogram” : used to identify datagrams
longer than 65,536 bytes
• Routing extension header: used to specify the
route to be taken by a datagram
Copyright 2002, S.D. Personick. All Rights Reserved.
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IPv6 Extension Header Types
• Authentication extension header: verification
of the sender’s identity-- used to embed a
digital signature
• Encryption security payload extension
header: used to manage encrypted payloads
• See “Controversies” pp447-448 of
Tanenbaum
Copyright 2002, S.D. Personick. All Rights Reserved.
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Emerging Protocols: RSVP
• Used to describe bandwidth and/or quality-ofservice requirements to the network (I.e., to
the routers in the network, and their
associated management entities)
• Does not specify or provide insights into how
the network will arrange to actually deliver on
these requests
Copyright 2002, S.D. Personick. All Rights Reserved.
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Emerging Protocols
• IP/Telephony Gateways: Protocols to support
interoperability between the Internet and
traditional telephony networks (“Internet
telphony” applications)
• IPSec: Protocols to support secure
communication using the Internet (or private
Internets)
Copyright 2002, S.D. Personick. All Rights Reserved.
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