Cisco Systems A9014CFD manual IPv6 Addressing and Discovery, Static Configuration, 32-4

Chapter 32 IPv6 Support on the Cisco ASR 901 Router

Information About IPv6 Support on the Cisco ASR 901 Router

Table 32-1	Compressed IPv6 Address Formats
IPv6 Address Type		Preferred Format	Compressed Format
Unicast		2001:0:0:0:DB8:800:200C:417A	2001::DB8:800:200C:417A
Loopback		0:0:0:0:0:0:0:1	::1
Unspecified		0:0:0:0:0:0:0:0	::

The loopback address listed in Table 32-1are used by a node to send an IPv6 packet to itself. The loopback address in IPv6 functions the same as the loopback address in IPv4 (127.0.0.1).

Note The IPv6 loopback address cannot be assigned to a physical interface. A packet that has 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.

The unspecified address listed in Table 32-1indicates the absence of an IPv6 address. For example, a newly initialized node on an IPv6 network may use the unspecified address as the source address in its packets until it receives its IPv6 address.

Note The IPv6 unspecified address cannot be assigned to an interface. The unspecified IPv6 addresses must not be used as destination addresses in IPv6 packets or the IPv6 routing header.

An IPv6 address prefix, in the format ipv6-prefix/prefix-length, can be used to represent bit-wise contiguous blocks of the entire address space. The ipv6-prefixmust be in the form documented in RFC 2373 where the 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:DB8:8086:6502::/32 is a valid IPv6 prefix.

For more information on IPv6 Addressing and Basic Connectivity, see the Implementing IPv6 Addressing and Basic Connectivity chapter of IPv6 Configuration Guide, at the following location:

http://www.cisco.com/en/US/docs/ios-xml/ios/ipv6/configuration/15-2mt/ip6-addrg-bsc-con.html

IPv6 Addressing and Discovery

The IPv6 addressing and discover consists of static and autoconfiguration of addresses – both global and link local addresses. IPv6 differs from IPv4 in that same interface can have multiple IPv6 addresses assigned to it. The Cisco ASR 901 router supports both IPv4 and multiple IPv6 addresses on the same Loopback and SVI interface. The link-local addresses are automatically generated (if ipv6 enable command is configured) from the MAC-address of the interface as soon as the SVI comes up.

Static Configuration

Static configuration is the manual process of defining an explicit path between two networking devices. The administrator of the network manually enters the IPv6 addresses, subnet masks, gateways, and corresponding MAC addresses for each interface of each router into a table. Static configuration

	Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
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