Transcript Topic 23
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. 1 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. 2 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. 3 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. 4 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. 5 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. 6 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. 7 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. 8 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. 9 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. 10