The Seattle SAGE Group
An Advanced Overview of IPv6
Addressing in IPv6 - Part 1
- Most pessimistic view is 1564 addresses per square meter for the
planet earth.
- A full address is comprised of 128 bits, or 16 octets
- Address representation in text
- :: means the part enclosed by the :'s pads to enough 0's to fill
the 128 bit address
- IPv4 representation x:x:x:x:x:x:x:x:x:x:x:x:d.d.d.d so we can refer
to 0:0:0:0:0:0:0:0:0:0:0:0:144.100.5.34 as ::144.100.5.34
- Address types Part 1:
- Unicast
- Assigned to 1 interface
- Could self-config by listening for router advertisement of
subnet & appending MAC address to get full IPv6 address
- Unspecified 0::0
- Loopback 0::1
- Anycast
- Sent to closest (by hop) address in group.
- Allows providers to have multiple routers connected at various
places in infrastructure
- Multicast
- FF:f1(1 bit):f2(1 bit):f3(1 bit):f4(1 bit):S(4 bit):GroupID
- f1-f3 are reserved flags, set to 0
- f4 = 0, for "well known" mcast addrs, assigned by global internet
- f4 = 1, for non-permanent mcast addrs, assigned "locally"
- "S" is scope value
- 0 is reserved
- 1 is for node only
- 2 is for link only (not routed)
- 3,4 unassigned
- 5 is for site only
- 6,7 unassigned
- 8 is for organization only
- GroupID
- 0 is reserved
- 1 is all nodes
- 2 is all routers
- C is DHCP server/relay agents
- Solicited Node address - FF02:0:0:0:0:1 + lower 32 bits of [uni|any]cast address.
Reduces # of multicast groups a node must join if different providers have routes
to same node.
