Link-Local Address - Cisco AP776A - Nexus Converged Network Switch 5020 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 NX-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 47-2
000000U0

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 47-3
1111 1110 10
Cisco MDS 9000 Family CLI Configuration Guide
47-4
Interface Identifier Format
00 90 27 17
00 90 27
FF FE
00 90 27 FF FE
U = 0
Where U is 0 (not unique)
or 1 (unique)
U = 1
02 90 27 FF FE
Link-Local Address Format
0
FE80::/10
10 bits
Chapter 47
FC 0F
17 FC 0F
17 FC 0F
17 FC 0F
128 bits
Interface ID
Configuring IPv6 for Gigabit Ethernet Interfaces
Figure
Figure 47-3 shows the structure of a
OL-18084-01, Cisco MDS NX-OS Release 4.x
47-2).