Siemens S323 User Manual
UMN:CLI User Manual
SURPASS hiD 6615 S223/S323 R1.5
340 A50010-Y3-C150-2-7619
10.2.4.6
OSPF Maximum Transmission Unit (MTU)
Router verifies MTU when DD (Database Description) is exchanging among the routers
on OSPF networks. Basically, OSPF network can not be organized if there are different
sizes of MTUs between routers. Therefore MTU value must be consistent. Generally MTU
value is 1500 bytes on Ethernet interface.
on OSPF networks. Basically, OSPF network can not be organized if there are different
sizes of MTUs between routers. Therefore MTU value must be consistent. Generally MTU
value is 1500 bytes on Ethernet interface.
To configure MTU on OSPF interface, use the following command.
Command Mode
Description
ip ospf mtu
<576-65535>
Configures an MTU on OSPF interface.
no ip ospf mtu
Interface
Deletes a configured MTU on OSPF interface.
Configuration as above makes MTU consistently on same OSPF network; actual MTU
value on interface itself will not be changed.
value on interface itself will not be changed.
On the other hands, if there are two routers which have different MTU, it can be partici-
pated with OSPF network through the configuration that skips the verification of MTU
value when there is DD exchanging.
pated with OSPF network through the configuration that skips the verification of MTU
value when there is DD exchanging.
To configure the switch to skip the MTU verification in DD process, use the following
command.
command.
Command Mode
Description
ip ospf mtu-ignore
ip ospf
A.B.C.D mtu-ignore
Interface
Configures the switch to skip the MTU verification in
DD process.
DD process.
To configure the switch not to skip the MTU verification in DD process, use the following
command.
command.
Command Mode
Description
no ip ospf mtu-ignore
no ip ospf
A.B.C.D mtu-ignore
Interface
Configures the switch not to skip the MTU verification
in DD process.
in DD process.
10.2.4.7 OSPF
Priority
Routers have each role to exchange the information on OSPF network. DR (Designated
Router) is one of essential role to get and transmit the route information in the same area.
Router) is one of essential role to get and transmit the route information in the same area.
The router having the highest priority becomes DR (Designated Router). If there are
routers which have same priority, the highest router ID will be DR.
routers which have same priority, the highest router ID will be DR.
Normally, router has priority 1, but it can be changed to make DR through the configura-
tion of priority.
tion of priority.
To configure a priority of OSPF router, use the following command.
Command Mode
Description
ip ospf priority
<0-255>
ip ospf A.B.C.D
priority <0-255>
Interface
Configures a priority of OSPF router.
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