Quality of Service and performance characterization of IPv6 relative to IPv4

II.4.4 IPv6 address in Uniform Resource Locator (URL)

In a URL, IPv6 address is enclosed in squared brackets []

The following examples show the IPv6 address in URL:

http://[2001:1:4F3A::206:AE14]:8080/index.html

http://::192.168.2.35 can be represented as

http://[::192.168.2.35]/ipng/

Accessing IPv6 only web-sites assumes that you have connectivity to the 6bone (the word 6bone stands for "IPv6 backbone").

II.4.5 IPv6 types

IPv6 address is 128 bits identify for interface and can be categorized into the following types:

· Unicast: An IPv6 unicast is an identifier for a single interface. A packet sent to a unicast address is delivered to the interfaces identified by that address (An address for a single interface).

The IPv6 unicast examples are: Loopback, unsigned, scope address (link local, site local)

· Anycast: An IPv6 anycast address is an address that is assigned to more than one interface (typically belonging to different nodes), with the property that a packet sent to an anycast address is routed to the "nearest" interface having that address, according to the routing protocols measure of distance.

· Multicast: An IPv6 multicast address is an identifier for a group of interfaces (typically on different nodes). A packet sent to a multicast address is delivered to all interfaces identified by that address.

No broadcast in IPv6. Multicast is used instead, mostly on local links.^17(*)

II.4.6 Special addresses

There are a number of addresses with special meaning in IPv6:

· ::1/128 The loopback address is a local host address. If an application in a host sends packets to this address, the IPv6 stack will loop these packets back to the same host (corresponding to 127.0.0.1 in IPv4). This is a special address for the loopback interface, similar to IPv4 with its "127.0.0.1".

· ::/128 The address with all zeroes is an unspecified address, and is only to be used in software. This is a special address like "any" or "0.0.0.0" in IPv4.

· fe80::/10 The link-local prefix specifies that the address only is valid in the local physical link. The link local can only be used between nodes of the same link, it can not be routed. The link local is automatically configured on each interface.

· fec0::/10 The site-local prefix specifies that the address is only valid inside the local organization. The site local can only be used between nodes of the same site, it cannot be routed outside the site (it means Internet).

It is very similar to IPv4 private addresses.

· ::/96 (0:0:0:0:0:0:a.b.c.d/96 or in compressed format ::a.b.c.d/96)- the zero prefix was used for IPv4-compatible addresses (Used for automatic tunneling in transition mechanism).

· ::ffff:0:0/96 (0:0:0:0:0:ffff:a.b.c.d/96 or in compressed format ::ffff:a.b.c.d/96) - this prefix is used for IPv4 mapped addresses (in transition mechanism).

· ff00::/8 - The multicast prefix is used for multicast addresses.

There are no address ranges reserved for broadcast in IPv6. Applications are supposed to use multicast to the all-hosts group instead.^18(*)

* ¹⁷ http://www.faqs.org/rfcs/rfc2373.html (August 13, 2006)

* ¹⁸ http://en.wikipedia.org/wiki/Ipv6#Special_addresses (August 13, 2006)