3Com Switch 8800 Family Configuration Guide

Configuring OSPF 323
Use the ospf dr-priority and peer commands to set priorities with different
usages:
■ Use the ospf dr-priority command to set priority for DR selection.
■ The priority you use the peer command to set indicates whether the adjacent
router is eligible for election. If you specify the priority as 0 during neighbor
configuration, the local router considers that this neighbor is not eligible for
election, thus sending no Hello packets to this neighbor. This configuration can
reduce the Hello packets on the network during DR and BDR selection.
However, if the local router is DR or BDR, this router can also send Hello
packets to the neighbor with priority 0 to establish adjacency relations.
Configuring an Interval
Required for Sending
LSU Packets
Trans-delay seconds should be added to the aging time of the LSA in an LSU
packet. Setting the parameter like this mainly considers the time duration that the
interface requires for transmitting a packet.
The user can configure the interval of sending LSU message. Obviously, more
attention should be paid to this item over low speed networks.
Perform the following configuration in interface view.
By default, the LSU packets are transmitted per second.
Configuring the Cost for
Sending Packets on an
Interface
The user can control the network traffic by configuring different packet sending
costs for different interfaces.
Perform the following configuration in interface view.
For Switch 8800 Family series, the default cost for running OSPF on the VLAN
interface is 10.
Configuring to Fill the
MTU Field When an
Interface Transmits DD
Packets
OSPF-running routers use Database Description (DD) packets to describe their own
LSDBs during LSDB synchronization.
You can manually specify an interface to fill in the MTU field in a DD packet when
it transmits the packet. The MTU should be set to the real MTU on the interface.
Perform the following configuration in interface view.
Tab le 291 Configure an interval required for sending LSU packets
Operation Command
Configure an interval for sending LSU packets ospf trans-delay seconds
Restore the default interval for sending LSU packets undo ospf trans-delay
Tab le 292 Configure the cost for sending packets on an interface
Operation Command
Configure the cost for sending packets on an interface ospf cost value
Restore the default cost for packet transmission on the interface undo ospf cost