Configuring Neighbor Detection Protocol and Static Entries
IPv6 Neighbor Discovery Protocol supersedes IPv4 Address Resolution Protocol in
IPv6 networks. IPv6 nodes on the same network segme nt use Ne ighbor Discover y
to discover each other's presence, to determine each other's link-la yer addresses, to
find routers and to maintain reachability information about the paths to act ive
neighbors. The key parameters used to facilitate this process are the number of
attempts made to verify whether or not a duplicate address exists on the sa me
network segment, and the interval between neighbor solicitat ions used to ve rify
reachability information.
Command Attributes
Protocol Settings
• VLAN – VLAN ID (Range: 1-4093)
• IPv6 ND DAD Attempts – The numb er of consec utive neig hbor solic itation
messages sent on an interface during duplicate address detection. (Range: 0-600,
Default: 1)
- Configuring a value of 0 disables duplicate a ddress de tectio n.
- Duplicate address d etec tion det ermi nes i f a new uni cas t IP v6 addre ss alr eady
exists on the network before it is assigned to an interf ace.
- Duplicate address detection is s toppe d on any interf ace that has been
suspended (see “Creating VLANs” on page 11-6). While an interface is
suspended, all unicast IPv6 addresses assigned to that interface are placed in a
“pending” state. Duplicate address detection is automatically restarted when the
interface is administratively re-activated.
- An interface that is re-activated restarts duplic ate address detection for all
unicast IPv6 addresses on the interface. While duplicate address detection is
performed on the interface’s link-local address, the other IPv6 addresses remain
in a “tentative” state. If no duplicate link-local address is found, duplicate address
detection is started for the remaining IPv6 add resses.
- If a duplicate address is detected, it is set to “duplicate” state, and a warni ng
message is sent to the console. If a duplicate link-local address is detected, IPv6
processes are disabled on the interface. If a duplicate gl obal u nica st addres s is
detected, it is not used. All configuration commands a ssociat ed wit h a du plicate
address remain configured while the address is in “duplicate” state.
- If the link-local address fo r an inte rface is c han ged , d upl icate a ddress detection
is performed on the new link-local add ress, but no t for any of the IPv6 gl obal
unicast addresses already associated with the inter face .
•
IPv6 ND NS Interval
– The interval between transmitting IPv6 neighbor solicitation
messages on an interface. (Range: 1000-3600000 milliseconds;
Default: 1000 milliseconds is used for neighbor discovery operations,
0 milliseconds is advertised in router advertisements)
- This attribute specifies the interval betwee n transmi tting neigh bor solicitat ion
messages when resolving an address, or when probing the reachab ility of a
neighbor. Therefore, avoid using very short intervals for normal IPv6 operations.

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Setting the Switch’s IP Address (IP Version 6)

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