H3C S9500 Series Operation Manual page 261

Operation Manual – Routing Protocol
H3C S9500 Series Routing Switches
With OSPF, NBMA refers to the networks that are fully connected, non-broadcast
and multi-accessible. However, a p2mp network is not necessarily fully
connected.
DR and BDR are required on a NBMA network but not on p2mp network.
NBMA is the default network type. For example, if ATM is adopted as the link layer
protocol, OSPF defaults the network type on the interface to NBMA, regardless of
whether the network is fully connected. p2mp is not the default network type. No
link layer protocols are regarded as p2mp. You must change the network type to
p2mp by force. The commonest undertaking is to change a partially connected
NBMA network to a p2mp network.
NBMA forwards packets by unicast and requires configuring neighbors manually.
p2mp forwards packets by multicast.
Perform the following configuration in interface view.
Table 4-20 Configure a network type for an OSPF interface
Configure the network type on the interface
Restore the default network type of the
OSPF interface
By default, OSPF determines the network type based on the link layer type. After the
interface has been configured with a new network type, the original network type of the
interface is removed automatically.
4.2.12 Configuring NBMA Neighbors for OSPF
For an NBMA network, some special configurations are required. Since an NBMA
interface on the network cannot discover the adjacent router through broadcasting
Hello packets, you must manually specify an IP address for the adjacent router for the
interface, and specify whether the adjacent router is eligible for election.
Perform the following configuration in OSPF view.
Table 4-21 Configure the NBMA neighbors for OSPF
Configure the NBMA neighbors for OSPF
Remove the configured NBMA neighbors
By default, the preference for NBMA neighbor is 1.
Operation
Operation
4-19
Chapter 4 OSPF Configuration
Command
ospf network-type { broadcast |
nbma | p2mp | p2p }
undo ospf network-type
Command
peer ip-address
dr-priority-number ]
undo peer ip-address
[ dr-priority