H3C S7500 Series Ethernet Switches Command Manual

Command Manual – Routing Protocol
H3C S7500 Series Ethernet Switches Chapter 3 OSPF Configuration Commands
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Interface view
Parameters
broadcast: Specifies the network type as broadcast.
nbma: Specifies the network type as NBMA.
p2mp: Specifies the network type as point-to-multipoint.
p2p: Specifies the network type as to point-to-point.
Description
Use the ospf network-type command to configure the network type for an OSPF
interface.
Use the undo ospf network-type command to restore the default network type for an
OSPF interface.
OSPF divides networks into four types based on link layer protocol:
z Broadcast: If Ethernet or FDDI is adopted, OSPF defaults the network type to
broadcast.
z Non-Broadcast Multi-access (nbma): If Frame Relay, ATM, HDLC or X.25 is
adopted, OSPF defaults the network type to NBMA.
z Point-to-Multipoint (p2mp): OSPF will not default the network type of any link layer
protocol to p2mp. The general undertaking is to change a partially connected
NBMA network to p2mp network if the NBMA network is not fully-meshed.
z Point-to-point (p2p): If PPP, LAPB or POS is adopted, OSPF defaults the network
type to p2p.
If there is any router not supporting multicast addresses on a broadcast network, the
network type of the interface can be changed to NBMA. Alternatively, the network type
of the interface can be changed from NBMA to broadcast.
For a non-broadcast multi-accessible network to be of NBMA type, any two routers in
the network must be directly reachable to each other through a virtual circuit. In other
words, the network must be fully-meshed.
For a network not meeting this condition, the network type of the interface must be
changed to point-to-multipoint. In this way, routing information can be exchanged
between two routers not directly reachable to each other through another router that is
directly reachable to the two routers.
If only two routers run OSPF in the same network segment, the network type of the
interface can also be changed to point-to-point.
Note that you must use the peer command to configure the peer if the network type of
the interface is NBMA or manually changed to NBMA with the ospf network-type
command.