Configuring Ospf Network Types; Prerequisites - H3C S5800 Series Configuration Manual

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Configure a virtual link

Configuring OSPF Network Types

OSPF classifies networks into four types: broadcast, NBMA, P2MP, and P2P, upon the link layer
protocol.
Broadcast: When the link layer protocol is Ethernet or FDDI, OSPF considers the network type as
broadcast by default.
NBMA: When the link layer protocol is Frame Relay, ATM or X.25, OSPF considers the network
type as NBMA by default.
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.
Use the command...
area area-id
vlink-peer router-id [ hello
seconds | retransmit seconds |
trans-delay seconds | dead
seconds | simple [ plain | cipher ]
password | { md5 | hmac-md5 }
key-id [ plain | cipher ] password ]
*
4-25
Remarks
—
Required
You need to configure this command
on both ends of a virtual link.
Note that hello and dead intervals
must be identical on both ends of the
virtual link.