Link-Local Address - HP Cisco MDS 9020 - Fabric Switch Configuration Manual

About IPv6
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
Cisco MDS SAN-OS supports IEEE 802 interface types (for example, Gigabit Ethernet interfaces). The
first three octets (24 bits) are taken from the Organizationally Unique Identifier (OUI) of the 48-bit
link-layer address (MAC address) of the interface, the fourth and fifth octets (16 bits) are a fixed
hexadecimal value of FFFE, and the last three octets (24 bits) are taken from the last three octets of the
MAC address. The construction of the interface ID is completed by setting the Universal/Local (U/L)
bit—the seventh bit of the first octet—to a value of 0 or 1. A value of 0 indicates a locally administered
identifier; a value of 1 indicates a globally unique IPv6 interface identifier (see
Figure 46-2
U = 0
000000U0
U = 1

Link-Local Address

A link-local address is an IPv6 unicast address that is automatically configured on an interface using the
link-local prefix FE80::/10 and the interface identifier in the modified EUI-64 format. Link-local
addresses are used in the neighbor discovery protocol and the stateless autoconfiguration process. Nodes
on a local link can use link-local addresses to communicate.
link-local address.
Figure 46-3
1111 1110 10
FE80::/10
Cisco MDS 9000 Family CLI Configuration Guide
46-4
Interface Identifier Format
00 90 27 17 FC
00 90 27 17
FF FE
00 90 27 FF FE 17
Where U is 0 (not unique)
or 1 (unique)
02 90 27 FF FE 17
Link-Local Address Format
0
10 bits
Chapter 46
0F
FC 0F
FC 0F
FC 0F
128 bits
Interface ID
Configuring IPv6 for Gigabit Ethernet Interfaces
Figure
Figure 46-3 shows the structure of a
OL-16184-01, Cisco MDS SAN-OS Release 3.x
46-2).