Dd packet – H3C Technologies H3C S12500 Series Switches User Manual
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Figure 26 Hello packet format
Major fields of the hello packet are as follows:
•
Network mask—Network mask associated with the router's sending interface. If two routers have
different network masks, they cannot become neighbors.
•
HelloInterval—Interval for sending hello packets. If two routers have different intervals, they cannot
become neighbors.
•
Rtr Pri—Router priority. A value of 0 means the router cannot become the DR or BDR.
•
RouterDeadInterval—Time before declaring a silent router down. If two routers have different dead
intervals, they cannot become neighbors.
•
Designated router—IP address of the DR.
•
Backup designated router—IP address of the BDR.
•
Neighbor—Router ID of the neighbor router.
DD packet
Two routers exchange database description (DD) packets describing their LSDBs for database
synchronization. A DD packet contains only the headers of LSAs to reduce traffic between routers.