D-Link DGS-3324SR Product Manual - Page 183

xStack DGS/DXS-3300 Series Layer 3 Stackable Gigabit Ethernet Switch User Manual 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 Packet Length Router ID Area ID Checksum Authentication Type Authentication Authentication Field Version No. Type Packet Length Router ID Area ID Checksum Authentication Type Authentication Figure 6- 129. OSPF Packet Header Format Description The OSPF version number The OSPF packet type. The OSPF packet types are as follows: Type Description Hello Database Description Link-State Request Link-State Update Link-State Acknowledgment The length of the packet in bytes. This length includes the 24-byte header. The Router ID of the packet's source. A 32-bit number identifying the area that this packet belongs to. All OSPF packets are associated with a single area. Packets traversing a virtual link are assigned the backbone Area ID of 0.0.0.0 A standard IP checksum that includes all of the packet's contents except for the 64-bit authentication field. The type of authentication to be used for the packet. A 64-bit field used by the authentication scheme. 168