Prerequisites; Configuring The Ospf Network Type For An Interface As Broadcast; Configuring The Ospf Network Type For An Interface As Nbma - 3Com S7906E Configuration Manual

P2P: When the link layer protocol is PPP, LAPB, HDLC, or POS, OSPF considers the network type
as P2P by default.
You can change the network type of an interface as needed. For example:
When an NBMA network becomes fully meshed through address mapping, namely, when any two
routers in the network have a direct virtual link in between, you can change the network type to
broadcast, without manually configuring the neighbors.
When some routers in the broadcast network do not support multicast, you can change the network
type to NBMA.
An NBMA network is fully meshed, which means any two routers in the NBMA network have a
direct virtual link for communication. If direct connections are not available between some routers,
the type of interfaces associated should be configured as P2MP, or as P2P for interfaces with only
one neighbor.
If two interfaces on a link are both configured as the broadcast, NBMA or P2MP type, they cannot
establish a neighbor relationship unless they are on the same network segment.

Prerequisites

Before configuring OSPF network types, you have configured:
IP addresses for interfaces, making neighboring nodes accessible with each other at network layer.
OSPF basic functions.

Configuring the OSPF Network Type for an Interface as Broadcast

Follow these steps to configure the OSPF network type for an interface as broadcast:
To do...
Enter system view
Enter interface view
Configure the OSPF network
type for the interface as
broadcast
Configure a DR priority for the
interface

Configuring the OSPF Network Type for an Interface as NBMA

After configuring the network type of an interface as NBMA, you need to make some special
configurations.
Because NBMA interfaces cannot find neighbors via broadcasting Hello packets, you need to specify
neighbors and neighbor DR priorities. (A DR priority of 0 means the router does not have the DR
election right; a DR priority greater than 0 means the router has the DR election right).
Use the command...
system-view
interface interface-type
interface-number
ospf network-type
broadcast
ospf dr-priority priority
1-27
Remarks
—
—
Required
By default, the network type of an
interface depends on the link
layer protocol.
Optional
The default DR priority is 1.