Link-Local Address (LLAs)
Similar to APIPA APIPA addresses
Self-configured, Self-configured, non-routable
Provides Provides automatic communication on local subnet Defined as FE80:: /10.
The structure of LLAs:
Unique-Local Addresses (ULAs)
Similar to Private addresses ▪
They are not expected to be routable on the global Internet.
Defined as FC00 or FD00::/7
The structure of ULAs:
Multicast address
One-to-Many communication packets. Multicast packets are identifiable by their first byte. Defined as FF00::/8
In the second byte shown (the “00” of FF00), the second 0 is what’s called the scope. ▪
▪
Interface-local is 01, and link-local is 02 FF01:: is an interface-local multicast. multicast.
There are several well-known multicast addresses
Ex: if you want to send a packet to all nodes in the linklocal scope, ▪
▪
You send the packet to FF02::1 (FF02:0:0:0:0:0:0:1). The all-routers multicast address is FF02::2
Address Prefix
Scope of Use
2000:: /3
Global unicast space prefix
FE80:: /10
Link-local address prefix
FC00:: /7
Unique local unicast prefix
FF00:: /8
Multicast prefix
2001:DB8:: /32
Global unicast prefix use for documentation
::1 - ::/1
Reserved local loopback address
2001:0000: /32
Teredo prefix (discussed later in this chapter)
2002:: /16
6to4 prefix (discussed later in this chapter)
New Header Format
Not supported by current IPv4 routers
Router Upgrade Required Before Moving Movi ng To To IPv6
Dual stack
Tunneling
Running both IPv4 and IPv6 on the same network Utilizing the IPv4 address space for devices using only IPv4 addresses and utilizing the IPv6 address space for devices using IPv6 addresses Using an encapsulation scheme for transporting one address space inside another
Address Address translation
Using a higher-level application to transparently change one address type (IPv4 or IPv6) to the other so end devices are unaware one address space is talking to another
IPv6 Dual Stack
IPv6 Tunneling
Several tunneling mechanisms for tunneling IPv6 through the IPv4 address space. Used for unicast IPv6 communication across an IPv4 infrastructure. They include the following: ▪
▪
▪
Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) 6to4 Teredo
Intra-Site Automatic Tunnel Addressing Protocol P rotocol (ISATAP)
Allows IPv6 and IPv4 hosts to communicate through a ISATAP router ▪
By performing a type of address translation between IPv4 and IPv6.
Intended for use inside a private private network. Enabled by default in Windows Server 2008. “Tunnel “Tunnel Adapter Local Area Connection* 8” IPv4 embedded in IPv6 ▪
▪
e.g., FE80::5EFE:192.168.1.5 FE80::5EFE:192.168.1.5
All ISATAP clients receive an address for an ISATAP interface. The format of an ISATAP address is as follows: ▪
[64bits of prefix] [32bits indicating ISATAP] [32bits IPv4 Address]
ISATAP routers allows IPv4-only and IPv6only hosts to communicate with each other
6to4
Tunnels IPv6 traffic over IPv4 through 6to4 routers. Similar to ISATAP, but designed for public network (Internet) ▪
IPv4 is encapsulated in IPv6 Requires 6to4 routers ▪
Intended to be used on the Internets.
Router has public IP
2002:/16 prefix ▪
Router advertises advertises 2002: subnet ::/64 ▪
hosts auto configure 6to4 address
6to4 allows IPv6-only hosts to communicate over the Internet
Toredo
Similar to 6 to4 but unnecessary to upgrade edge routers. Toredo is used (Preferred) only when no other IPv6 translation is available. Allows clients behind an IPv4 NAT NAT to use IPv6 on the Internet Enabled by default in Windows Server 2008. “Tunnel Adapter Local Area Connection* 9” 2001::/32 prefix ▪
64 32 prefix
Teredo IPv4 Hex
64 Internett ID Interne
Neighbor Discovery Discovery is a set of messages and processes processes that determine relationships relationships between neighboring nodes. Some of the ND functions are:
Router discovery Prefix discovery Parameter discovery Address auto-configuration Address resolution Duplicate address detection
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