H3C Technologies H3C S10500 Series Switches - Manual (Page 122)

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configured on an IEEE 802 interface, the system can generate two addresses, public IPv6 address and
temporary IPv6 address.
• Public IPv6 address: Comprises an address prefix provided by the RA message, and a fixed
interface ID generated based on the MAC address of the interface.
• Temporary IPv6 address: Comprises an address prefix provided by the RA message, and a random
interface ID generated through MD5.
Before sending a packet, the system preferably uses the temporary IPv6 address of the sending interface
as the source address of the packet to be sent. When this temporary IPv6 address expires, the system
removes it and generates a new one. This enables the system to send packets with different source
addresses through the same interface. If the temporary IPv6 address cannot be used because of a DAD
conflict, the public IPv6 address is used.
The preferred lifetime and valid lifetime for temporary IPv6 addresses are specified as follows:
• The preferred lifetime of a temporary IPv6 address takes the value of the smaller of the following
values: the preferred lifetime of the address prefix in the RA message or the preferred lifetime
configured for temporary IPv6 addresses minus DESYNC_FACTOR (which is a random number
ranging 0 to 600, in seconds).
• The valid lifetime of a temporary IPv6 address takes the value of the smaller of the following values:
the valid lifetime of the address prefix or the valid lifetime configured for temporary IPv6 addresses.
Follow these steps to configure the temporary address function:
To do... Use the command... Remarks
Enter system view system-view —
Configure the system to generate and
preferably use the temporary IPv6
address of the sending interface as
the source address of the packet to be
sent
ipv6 prefer temporary-address
[ valid-lifetime preferred-lifetime ]
Required
By default, the system does
not generate or use a
temporary IPv6 address.
CAUTION:
•
You must also enable stateless address autoconfiguration on an interface if you need temporary IPv6
addresses to be generated on that interface. Temporary IPv6 addresses do not override public IPv6
addresses. Therefore, an interface may have multiple IPv6 addresses with the same address prefix but
different interface ID portions.
• If the public IPv6 address fails to be generated on an interface because of a prefix conflict or other
reasons, no temporary IPv6 address will be generated on the interface.
Configuring an IPv6 link-local address
IPv6 link-local addresses can be configured in either of the following ways:
• Automatic generation: The device automatically generates a link-local address for an interface
according to the link-local address prefix (FE80::/10) and the link-layer address of the interface.
• Manual assignment: IPv6 link-local addresses can be assigned manually.