Brocade Communications Systems Brocate Ethernet Access Switch 6910 - Manual (Page 654)

604 Brocade 6910 Ethernet Access Switch Configuration Guide
53-1002581-01
IPv6 Interface
29
Command Usage
• The prefix must be formatted according to RFC 2373 “IPv6 Addressing Architecture,” using 8
colon-separated 16-bit hexadecimal values. One double colon may be used in the address to
indicate the appropriate number of zeros required to fill the undefined fields.
• If a link local address has not yet been assigned to this interface, this command will
dynamically generate a global unicast address and a link-local address for this interface. (The
link-local address is made with an address prefix of FE80 and a host portion based the
switch’s MAC address in modified EUI-64 format.)
• Note that the value specified in the ipv6-prefix may include some of the high-order host bits if
the specified prefix length is less than 64 bits. If the specified prefix length exceeds 64 bits,
then the network portion of the address will take precedence over the interface identifier.
• If a duplicate address is detected, a warning message is sent to the console.
• IPv6 addresses are 16 bytes long, of which the bottom 8 bytes typically form a unique host
identifier based on the device’s MAC address. The EUI-64 specification is designed for devices
that use an extended 8-byte MAC address. For devices that still use a 6-byte MAC address (also
known as EUI-48 format), it must be converted into EUI-64 format by inverting the
universal/local bit in the address and inserting the hexadecimal number FFFE between the
upper and lower three bytes of the MAC address.
• For example, if a device had an EUI-48 address of 28-9F-18-1C-82-35, the global/local bit
must first be inverted to meet EUI-64 requirements (i.e., 1 for globally defined addresses and 0
for locally defined addresses), changing 28 to 2A. Then the two bytes FFFE are inserted
between the OUI (i.e., company id) and the rest of the address, resulting in a modified EUI-64
interface identifier of 2A-9F-18-FF-FE-1C-82-35.
• This host addressing method allows the same interface identifier to be used on multiple IP
interfaces of a single device, as long as those interfaces are attached to different subnets.
Example
This example uses the network prefix of 2001:0DB8:0:1::/64, and specifies that the EUI-64
interface identifier be used in the lower 64 bits of the address.
Console(config)#interface vlan 1
Console(config-if)#ipv6 address 2001:0DB8:0:1::/64 eui-64
Console(config-if)#end
Console#show ipv6 interface
VLAN 1 is up
IPv6 is enabled
Link-local address:
FE80::2E0:CFF:FE00:FD/64
Global unicast address(es):
2001:DB8::1:2E0:CFF:FE00:FD/64, subnet is 2001:DB8::1:0:0:0:0/64[EUI]
2001:DB8:2222:7272::72/96, subnet is 2001:DB8:2222:7272::/96[EUI]
Joined group address(es):
FF02::1:FF00:72
FF02::1:FF00:FD
FF02::1
IPv6 link MTU is 1500 bytes
ND DAD is enabled, number of DAD attempts: 3.
ND retransmit interval is 1000 milliseconds
ND advertised retransmit interval is 0 milliseconds
ND reachable time is 30000 milliseconds
ND advertised reachable time is 0 milliseconds
Console#