Ospf Packet Formats - D-Link dxs-3350sr Installation & User Manual

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
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:
DXS-3350SR Gigabit Layer 3 Switch
OSPF Packet Header
Type
Version No.
Checksum
Packet Length
Router ID
Area ID
Authentication Type
Authentication
Authentication
147