OSPF Type2 Message / DBD Packet (Database Descriptor)

DBD (Database Description or Type2 OSPF Packet) is a sort of summary of the OSPF Database in a router. DBD is used to check if the LSDB between 2 routers is the same.

These packets are exchanged when an adjacency is being initialized. They describe the topology information a router has in its database. DBD uses poll-response procedure (master/slave). Master sends DBD packets/polls which are acknowledged by the slave.

 

 

 

Consider the simple below topology with two Routers:

As soon as we enable OSPF on the router interfaces, it starts exchanging Hello and DBD Packets.

It is obvious from the below detail, spend some time with it to understand it fully:

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Waqas Karim is a seasoned Network Expert … Geek. He is the founder of ATech. ATech was started for learning & sharing. Over time the platform has grown to include other resources which continue to attract fellow networkers. Today it sees upward trend of a hundred thousand visitors per month, scattered all over the globe. His specialty is networking, but his interest & expertise spans from traditional IT to Network Security including Programming, Virtualization, Service Provider & so on... no matter the badge on the box. He is CCIE Certified (CCIE#56732) in addition to below badges: Telecom Engineer (BE) + CCIE-RS (CCIE#56732) + Huawei Certified (HW#706632) + MBA Microsoft Certified MCITP, MCSE#109*26, CCNP-Sec, CCNP-SP, CCNA-DC, CompTIA Security+, Nokia NRS-I, JNCIA, ITIL Certified (ITIL#*6373), CEH (Certified Ethical Hacker).

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Alisha Sha
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Alisha Sha

Good

Ravi Sharma
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Ravi Sharma

DBD & LSU have same purpose?

Imran Khan
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Imran Khan

This example cleared Neighborship forming in my mind. Good!

Pavan Kumar
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Pavan Kumar

Nice!!!

Joshua
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Joshua

How neighborship formed in OSPF?

Jayden
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Jayden

I had no clear idea how DBD works. Thanks for sharing the info?
thank you.