To recap on IPv4 address types:
- Unicast – represents a single host
- Multicast – represents a group of hosts
- Broadcasts – represents all hosts
IPv6 Address Types:
- Unicast – one to one
- Multicast – one to group
- Anycast – one to more than one! (More to follow)
Aggregateable Global Unicast Address
- Or otherwise known as ‘Global Unicast Address‘ 🙂
- This address is equivalent to the public IPv4 address classes.
- These addresses are fully routable and can be used for Internet access.
- The word “aggregateable” refers to the ability to aggregate, or summarize, these addresses to make routing more efficient.
- The range of IPv6 global unicast addresses is 2000::/3 (any address that begins with 001).
Link Local Address
- An address that is kept on the local link.
- Prefix of Fe80::/10 followed by the interface identifier from the previous post.
More to follow!
Site Local Address (NO LONGER A PART OF IPv6)
These addresses were originally designed to be the equivalent of an IPv4 RFC 1918 private IP address.
Identifying IPv6 Addressing
- 001 – Global address
- 1111 1111 – Multicast (FF)
- 1111 1110 10 – Link Local (FE80)
- ::x.x.x.x or 0:0:0:0:0:0:x.x.x.x – IPv4-compatible address (Any IPv6 address with the first 96 bits set to zero is an IPv4-compatible address.)
Reserved IPv6 Addresses
IPv4 has the Loopback IP address of 127.0.0.1, the IPv6 equivalent is:
- IP v6 Loopback: 0000:0000:0000:0000:0000:0000:0000:0001
- Using Leading Zero Compression Only: 0:0:0:0:0:0:0:1
- Combining Leading Zero and Zero Compression: ::1
Unspecified IPv6 Address
- IPv6 Unspecified Address: 0000:0000:0000:0000:0000:0000:0000:0000
- Using Zero Compression: 0:0:0:0:0:0:0:0, or just ::/128
- Since the unspecified address is ::/128, it follows that the default route for IPv6 is ::/0
IPv6 to IPv4 Conversion Example
IPv6 Address To Convert: ::D190:4E71
The double-colon is zero compression in action, so now we need to convert the lower 32 bits into decimal.
- Hex D1 = Decimal 209 (D = 13, 13 * 16 = 280 + how many 1s go into 1? 1! = 209. Hex revision? ;))
- Hex 90 = Decimal 144
- Hex 4E = Decimal 78
- Hex 71 = Decimal 113
The IPv4 address that was embedded into the IPv6 address is 188.8.131.52.
- IPv4 multicast addresses are Class D addresses with a first octet value of 224 – 239.
- Any address that begins with “1111 1111”, or “FF” in hex, is a multicast address — the full prefix being FF00::/8.
Local Link Only Notable Addresses
- FF02::1 — All nodes on the local link
- FF02::2 — All routers “”
- FF02::9 — All RIP routers “”
- FF02::A — All EIGRP routers “”
- FF02::1:FFzz:zzzz/104 — Solicited-node address. These are used in Neighbor Solicitation messages – more about these very soon. The “z”s are the rightmost 24 bits of the unicast/address of the node.
- This is a combination of a unicast and multicast.
- An anycast address is a unicast address assigned to multiple interfaces.
- A sender transmits an anycast packet in the same manner it would a unicast packet and when the router receives the anycast packet, the router then sends that packet to the closest device with that anycast address.
How IPv6 defines what is ‘closest’?
- It’s the first learned directly connected neighbor – if there are directly connected neighbors.
- If that’s not the case, it’s simply the closest neighbor as determined by the routing protocol metric.
More to follow..