H3C Technologies H3C S12500 Series Switches - Manual (Page 95)

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• Broadcast—When the link layer protocol is Ethernet, OSPF considers the network type as
broadcast by default.
• NBMA—When the link layer protocol is Frame Relay, OSPF considers the network type as NBMA
by default.
• P2P—When the link layer protocol is PPP or HDLC, OSPF considers the network type as P2P by
default.
Follow these guidelines when you change the network type of an interface:
• When an NBMA network becomes fully meshed (any two routers in the network have a direct
virtual circuit in between), change the network type to broadcast to avoid manual configuration of
the neighbors.
• If some routers in the broadcast network do not support multicasting, change the network type to
NBMA.
• An NBMA network must be fully meshed. If it is partially meshed, you can change the network type
to P2MP to simplify configuration and save costs.
• If a router on an NBMA network has only one neighbor, you can change the network type to P2P
to save costs.
Two broadcast-, NBMA-, P2MP-type interfaces can establish a neighbor relationship only when they are
on the same network segment.
Configuration prerequisites
Before you configure OSPF network types, complete the following tasks:
• Configure IP addresses for interfaces to ensure IP connectivity between neighboring nodes.
• Enable OSPF.
Configuring the broadcast network type for an interface
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter interface view.
interface interface-type
interface-number
N/A
3. Configure the OSPF network
type for the interface as
broadcast.
ospf network-type broadcast
By default, the network type of an
interface depends on the link layer
protocol.
4. Configure a router priority for
the interface.
ospf dr-priority priority
Optional.
The default router priority is 1.
Configuring the NBMA network type for an interface
After you configure the network type of an interface as NBMA, you must specify neighbors and their
router priorities because NBMA interfaces cannot find neighbors by broadcasting hello packets.
A router priority of 0 means the router does not have the DR election right. A router priority greater than
0 means the router has the DR election right.