TAILIEUCHUNG - IPv6 @ Cisco
The Cisco software feature documentation in this configuration guide often includes information about features that are shared across software releases and platforms. This guide may contain information that is not specific to your particular platform or is not supported in your software release. Additionally, some configuration guides contain content that may be superseded by documentation from a later software release. | IPv6 @ Cisco Patrick Grossetete Cisco Systems Cisco IOS IPv6 Product Manager pgrosset@ Ansar Pasha Cisco Systems Network Consultant, Govt & Defense, South ansar@ Agenda IPv6 Business Case IPv6 Protocols & Standards Integration and Transition Cisco IOS IPv6 Roadmap IPv6 Deployment scenarios References IPv6 - So what’s really changed ?! Expanded Address Space Address length quadrupled to 16 bytes Header Format Simplification Fixed length, optional headers are daisy-chained IPv6 header is twice as long (40 bytes) as IPv4 header without options (20 bytes) No checksumming at the IP network layer No hop-by-hop segmentation Path MTU discovery 64 bits aligned Authentication and Privacy Capabilities IPsec is mandated No more broadcast IPv4 & IPv6 Header Comparison Version IHL Type of Service Total Length Identification Flags Fragment Offset Time to Live Protocol Header Checksum Source Address Destination Address Options Padding Version Traffic Class Flow Label Payload Length Next Header Hop Limit Source Address Destination Address IPv4 Header IPv6 Header - field’s name kept from IPv4 to IPv6 - fields not kept in IPv6 - Name & position changed in IPv6 - New field in IPv6 Legend How Was IPv6 Address Size Chosen? Some wanted fixed-length, 64-bit addresses Easily good for 1012 sites, 1015 nodes, at .0001 allocation efficiency (3 orders of magnitude more than IPv6 requirement) Minimizes growth of per-packet header overhead Efficient for software processing Some wanted variable-length, up to 160 bits Compatible with OSI NSAP addressing plans Big enough for auto-configuration using IEEE 802 addresses Could start with addresses shorter than 64 bits & grow later Settled on fixed-length, 128-bit addresses (340,282,366,920,938,463,463,374,607,431,768,211,456 in all!) IPv6 Addressing IPv6 Addressing rules are covered by multiples RFC’s Architecture defined by RFC 3513 (obsoletes RFC 2373) Address Types are : Unicast : One to One (Global, Link local, .
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