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IPv6 Addressing Details. LAC NIC VII October 26, 2004 Wilfried Woeber woeber@cc.univie.ac.at. topics. Header (format, extension header) Addresstypes Configuration Scope, lifetime. Header. fixed-length 40 byte header checksum removed no options in base header
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IPv6 Addressing Details LACNICVII October 26, 2004 Wilfried Woeber woeber@cc.univie.ac.at
topics • Header (format, extension header) • Addresstypes • Configuration • Scope, lifetime
Header • fixed-length 40 byte header • checksum removed • no options in base header • new flow label field (use is currently not defined) • faster packet processing (with hardware support) • options in flexible and extensible extension headers (can be transparent for transit nodes)
Extension Headers • hop-by-hop (various, e.g. discard packet w/o ICMP) • routing (address list source routing) • fragment (fragmentation only done by source) • destination options (various , e.g. discard packet w/o ICMP) • authentication (integrity and data origin auth.) • encapsulating security payload (confidentiality)
Addresstypes • unicast (identifier for single interface, packet is sent to interface identified by that address) • anycast (identifier for a set of interfaces, packet is sent to one of the interfaces identified by that address (the 'nearest' one)) • multicast (identifier for a set of interfaces, packet is sent to all interfaces identified by that address)
Ext. Representation / Format • x:x:x:x:x:x:x:x x is 16bit hex-value • leading zeros are not necessary &series of zeros can be compressed2058:0000:0000:000b:0800:ac23:0001 = 2058::b:800:ac23:1 • prefix length is written in CIDR notation3ffe:8034:80:1:2a0:24ff:fe9d:5094/64
Unicast Addresses • unspecified (::/128) [ no IPv4 equivalent ] • loopback (::1/128) [similar to 127.0.0.1 in IPv4] • link-local (prefix fe80::/10 + interface identifier) • site local (prefix fec0::/10 + interface identifier) [killed] • global (e.g. prefix 2001:600::/23 for RIPE region) • IPv4-compatible address (::131.130.1.201) • IPv4-mapped address (::ffff: 131.130.1.201) • IPv6 addr. cont. encoded OSI NSAP addr.
Interface Identifier • used to identify interfaces on a link • has to be unique on that link • 64 bits long, modified EUI-64 format • created from -) IEEE EUI-64 identifier -) IEEE 802 48 bit MAC -) any other link identifier -) manually chosen identifier • uniqueness can be independent of address • ==> or picked at random to protect privacy!
Anycast Addresses • allocated from the unicast address space nodes must be explicitly configured • host-routes are needed !!! most likely NO global anycast sets • status: no anycast for hosts, only for routers: subnet-router anycast address same as unicast address, but interface identifier set to zero
Multicast Addresses • ff00::/8 • flags: 3 high-order reserved, permanently/ non-permanently • scope: various scopes (e.g. link-local, org-local, global) • group id: identifies multicast-group • some multicast addresses are reservede.g.: all nodes addr (ff0x::1) all routers addr (ff0x::2) solicited-node address • routers must not forward any multicast packet beyond the scope indicated by the scope field
Lifetime / Scope lifetime • valid preferred • valid deprecated - not to be used to initiate new communication • invalid - must not be used (neither source nor destination) scope