Ipv6 Unicast Addresses; Aggregatable Global Addresses - Cisco Nexus 7000 Series Configuration Manual

Chapter 3 Configuring IPv6
S e n d d o c u m e n t c o m m e n t s t o n e x u s 7 k - d o c f e e d b a c k @ c i s c o . c o m .
A node may use the loopback address listed in
address in IPv6 is the same as the loopback address in IPv4. For more information, see
"Overview."
Note You cannot assign the IPv6 loopback address to a physical interface. A packet that contains the IPv6
loopback address as its source or destination address must remain within the node that created the packet.
IPv6 routers do not forward packets that have the IPv6 loopback address as their source or destination
address.
You cannot assign an IPv6 unspecified address to an interface. You should not use the unspecified IPv6
Note
addresses as destination addresses in IPv6 packets or the IPv6 routing header.
The IPv6-prefix is in the form documented in RFC 2373 where the IPv6 address is specified in
hexadecimal using 16-bit values between colons. The prefix length is a decimal value that indicates how
many of the high-order contiguous bits of the address comprise the prefix (the network portion of the
address). For example, 2001:0DB8:8086:6502::/32 is a valid IPv6 prefix.

IPv6 Unicast Addresses

An IPv6 unicast address is an identifier for a single interface, on a single node. A packet that is sent to
a unicast address is delivered to the interface identified by that address. This section includes the
following topics:
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Aggregatable Global Addresses

An aggregatable global address is an IPv6 address from the aggregatable global unicast prefix. The
structure of aggregatable global unicast addresses enables strict aggregation of routing prefixes that
limits the number of routing table entries in the global routing table. Aggregatable global addresses are
used on links that are aggregated upward through organizations, and eventually to the Internet service
providers (ISPs).
Aggregatable global IPv6 addresses are defined by a global routing prefix, a subnet ID, and an interface
ID. Except for addresses that start with binary 000, all global unicast addresses have a 64-bit interface
ID. The IPv6 global unicast address allocation uses the range of addresses that start with binary value
001 (2000::/3).
OL-20002-02
Aggregatable Global Addresses, page 3-3
Link-Local Addresses, page 3-5
IPv4-Compatible IPv6 Addresses, page 3-5
Unique Local Addresses, page 3-6
Site-Local Address, page 3-7
Figure 3-1 shows the structure of an aggregatable global address.
Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide, Release 4.x
Table 3-1 to send an IPv6 packet to itself. The loopback
Information About IPv6
Chapter 1,
3-3