CS4550 Computer Networks II IP Version 6

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CS4550 Computer Networks IIIP Version 6

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IP topics

• Why IPv6? (1)
• IPv6 Challenges (1)
• IPv6 Addressing and Packet Format (3)
• IPv6 Routing (2)
• IPv6 Other Topics (1)
• IPv6 Related Standards (1)
• Transitioning to IPv6 (1)
• IPv6 Current Status

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Why IPv6?

• IPv4 Proposed in 1975, adopted 1981
• Served well, but 24 years old!
• Address Depletion
• Explosion in growth of routing tables
• non-hierarchical in nature
• Routing Performance
• Packets costly to analyze enroute
• Security Issues - no organic support
• New technologies
• telephony, video, e-commerce, etc
• Piece of the puzzle to enable new services
• Gigabit Ethernet, RSVP, IPv6, etc

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IPv6 Challenges

• Backwards Compatibility
• MUST work with existing equipment
• Perpetual co-existence with IPv4
• Co-exist with current standards/protocols
• New v6 aware protocols to take advantage of v6
  features
• Reduce Latency provide QOS!!!
• Enable streaming data

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IPv6 addressing

• IPv4 Address Space
• 232 4,294,967,296 -- but many wasted
• CIDR has helpedBUT is a band aid approach
• IP masquerading, proxies, NATs
• IPv6 Address Space
• 2128 3.4x 1038 addresses
• 340,282,366,920,938,463,374,607,431,768,211,456
  addresses
• hierarchical.aggregatable (sic)
• Address Notation XXXXXXXX
• where X16 bits
• FEDCBA9876543210FEDCBA9876543210
• 108000088002C417C
• 108088002C417C

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IPv6 addressing hierarchy

• Continuously bit-wise maskable
• may formats possible
• fully customizable at each level
• Format for auto configuration
• Also supports aggregate routes

Received from router during auto-config
Host Provided
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IPv6 Packet Format

• MUCH Simplified
• Fixed Length - 40 bytes
• Extension Headers
• 8 Optional Headers Defined
• Authentication Header (MD5)
• MD5
• Encapsulating Security Payload
• 56bit DES
• HMAC w/MD5 or w/SHA-1

1 hop-by-hop (only one examined in route) 2
Fragment 3 destination options 4 routing 5
Authentication 6 Encryption
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IPv6 Routing

• Routers CANNOT Fragment
• Fragmentation done at source host
• guaranteed minimum 576 byte path
• (93) efficiency
• Shorter Simplified Headers
• Faster Analysis
• Most Optional Headers Ignored in Routing
• Hierarchical Addressing
• Smaller Routing Tables
• Route aggregation similar to CIDR
• Flow Control Labels
• Flow Control Labeled packets are switched

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IPv6 Routing - Streaming

• Flow Control Labels
• Flow Control Labeled packets are switched
• location of flow label
• RSVP Protocol Allows bandwidth reservation
• Packet Prioritization
• via Class of Service
• Jumbograms
• Up to 4gb packets if MTU allows
• Multicast Support
• No broadcasting
• Allows subscription to a broadcast
• Scope field for broadcast
• via IGMP/ICMP

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IPv6 Other Features

• Packet Authentication
• MD5 - Proposed Default
• Packet Encryption
• 56bit DES CBC Mode - Propose Default
• Plug Play
• Multicast
• -built in support
• Anycast
• Any router

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Related Standards

• 21 of 51 Existing Internet Standards Affected
• DNS
• Support for 32bit address records
• AAAA Records
• Routing Protocols
• Modification of Interior Exterior Protocols
• ICMPv6
• IGMCav6
• Potentially any upper layer requiring knowledge
  of IP address

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IPv6 Transition

• IPv4 Address Translation
• Dual Protocol Stacks
• IPv6 Tunneled Over IPv4
• IPX/SPX Translation
• Extension Headers
• 8 Optional Headers Defined
• Authentication Header (MD5) - RFC 1827
• Encapsulating Security Payload (56bit DES) - RFC
  1829

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IPv6 Current Status

• Many IPv6 Stacks
• Add-ons for MS Windows, Sun, Macs
• MS has beta IPv6 stack for NT
• Router Operating Systems
• Cisco, Bay Networks have IPv6 support
• Following are approved RFCs (Dec 98)
• RFC 2492 - IPv6 Over ITM RFC 2472 - IPv6 Over
  PPP
• RFC 2470 - IPv6 over TR RFC 2466 - IPv6 ICMPv6
  Group
• RFC2464 - IPv6 over Ethernet RFC 2463 - ICMP for
  IPv6
• RFC 2462 - IPv6 Auto configuration RFC 2460 -
  IPv6 Specification
• RFC 2402 - IP Authentication Hdr RFC 2406 - IP
  Encapsulating Security Payload