D-Link DGS-3324SR User Manual page 116

D-Link DGS-3324SR Layer 3 Stackable Gigabit Ethernet Switch
Adjacencies on Point-to-Point Interfaces
OSPF Routers that are linked using point-to-point interfaces (such as serial links) will always form adjacencies.
The concepts of DR and BDR are unnecessary.
OSPF Packet Formats
All OSPF packet types begin with a standard 24 byte header and there are five packet types. The header is
described first, and each packet type is described in a subsequent section.
All OSPF packets (except for Hello packets) forward link-state advertisements. Link-State Update packets, for
example, flood advertisements throughout the OSPF routing domain.
OSPF packet header
Hello packet
Database Description packet
Link-State Request packet
The Link-State Update packet
Link-State Acknowledgment packet
The OSPF Packet Header
Every OSPF packet is preceded by a common 24-byte header. This header contains the information necessary
for a receiving router to determine if the packet should be accepted for further processing.
The format of the OSPP packet header is shown below:
OSPF Packet Header
Version No.
Type
Router ID
Area ID
Checksum
Authentication
Authentication
101
Packet Length
Authentication Type