IT Certification

OSPF link state protocol is the use of HELLO packets to discover neighbors and establish a relationship between the use of UPDATE packet to send updates, NOTIFICATION packet to this error and so on, we set out tables of view

1, Hello
2, Database Description
3, Link State Request
4, Link State Update
5, Link State Acknowledgement

Link state protocol, one of the characteristics of multicast is that it features, the distance vector to replace the radio characteristics of the agreement, but not all of the package, at any time is issued by the multicast packet and unicast it is also an important tool for .

First, we discuss only HELLO packets in unicast special case:

Unicast
1, NBMA
2, Virtual-Link

Multicast
3, Broadcast
4, Point-to-Point
5, Point-to-Multipoint

Second, the way to say, HELLO time and DEAD time was 10 seconds, 40 seconds is the (4 times the relationship):
point-to-point
broadcast

HELLO time DEAD time is 40 seconds, 120 seconds is
Point-to-Multipoint
NBMA

III, DR and BDR election
The need for elections DR, BDR is
Automatic Election Broadcast
Point-to-Multipoint automatic election
Manually specified NBMA

Elections without DR, BDR is
Point-to-Point without election