Adding an NBMA neighbor

Add an NBMA neighbor for each interface that is eligible to become the DR.

An NMBA interface with a positive nonzero router priority is eligible to become the DR for the NBMA network and is configured with the identification of all attached routers, IPv6 addresses, and router priorities.

Before you begin

  • Identify the following information:

    • specific interfaces to include in the NBMA network

    • the IPv6 address for each interface

    • the router priority for each interface

    • the hello interval for the network

    • the router dead interval for the network

    • the poll interval for the network

About this task

In contrast to a broadcast network where switches multicast (send to AllSPFRouters and AllDRouters) certain OSPF protocol packets, switches replicate and send NBMA packets to each neighboring router as unicast. NBMA networks drop all OSPF packets with destination addresses AllSPFRouters and AllDRouters. Because the NBMA network does not broadcast, you must manually configure a list of neighbors and priorities for all routers in the network that can become the DR. Potential DRs use a positive nonzero router priority.

Procedure

  1. Enter Interface Configuration mode:

    enable

    configure terminal

    interface GigabitEthernet {slot/port[/sub-port][-slot/port[/sub-port]][,...]} or interface vlan <1–4059>

    Note

    Note

    If the platform supports channelization and the port is channelized, you must also specify the sub-port in the format slot/port/sub-port.

  2. Create a new NBMA neighbor:

    ipv6 ospf nbma-nbr WORD<0-43> <0-255>

  3. Change the priority of an existing NBMA neighbor:

    ipv6 ospf nbma-nbr WORD<0-43> priority <0-255>

Example

Create an NBMA neighbor that will not become the DR:

Switch:1(config-if)#ipv6 ospf nbma-nbr fe80:0:0:0:8217:7dff:fe76:8a03 0

Variable definitions

Use the data in the following table to use the ipv6 ospf nbma-nbr command.

Variable

Value

priority <0-255>

Specifies the priority to use for this neighbor in the designated router election process. A value of 0 indicates the neighbor cannot become the designated router. The higher the priority value, the higher chance the switch will win the election process. The default is 1.

WORD<0-43>

Specifies the IPv6 address of the neighbor.

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