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Dd packet – H3C Technologies H3C SR8800 User Manual

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Figure 26 Hello packet format

Major fields:

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 Pr—Router priority. A value of 0 means the router cannot become the DR/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.