3Com Switch 7757, Configuration Manual

Page: 312 / 940

312 C
HAPTER
34: OSPF C
ONFIGURATION
n
■
You must use the stub command on all the routers connected to a stub area to
configure the area with the stub attribute.
■
You must use the nssa command on all the routers connected to an NSSA area
to configure the area with the NSSA attribute.
OSPF Network Type
Configuration
OSPF divides networks into four types by link layer protocol. See “OSPF Network
Type” on page 303. An NBMA network must be fully connected. That is, any two
routers in the network must be directly reachable to each other through a virtual
circuit. However, in many cases, this cannot be implemented and you need to use
a command to change the network type forcibly.
Configure the interface type as P2MP if not all the routers are directly accessible
on an NBMA network. Change the interface type to P2P if the router has only one
peer on the NBMA network.
In addition, when configuring a broadcast network or NBMA network, you can
also specify DR priority for each interface to control the DR/BDR selection in the
network. Thus, the router with higher performance and reliability can be selected
as a DR or BDR.
Configuration
Prerequisites
Before configuring the network type of an OSPF interface, perform the following
tasks:
■
Configuring the network layer address of the interface so that the adjacent
node is reachable at network layer
■
Performing basic OSPF configuration
Configuring the
Network Type of an
OSPF Interface
Create and configure a virtual link vlink-peer router-id
[ hello seconds |
retransmit seconds |
trans-delay seconds |
dead seconds | simple
password | md5 keyid
key ]*
Optional
For a virtual link to take
effect, you need to use
this command at both
ends of the virtual link and
ensure consistent
configurations of the
hello , dead , and other
parameters at both ends.
Table 232 Configure OSPF area attributes
Operation Command Description
Table 233 Configure the network type of an OSPF interface
Operation Command Description
Enter system view system-view -
Enter interface view interface interface-type
interface-number
-
Configure the network type of the
OSPF interface ospf
network-type
{ broadcast
| nbma | p2mp | p2p }
Optional
By default, the network
type of an interface
depends on the physical
interface.