D-Link DES-3326 Bedienungsanleitung Seite 74

Field
Version No.
Type
Packet Length
Router ID
Area ID
Checksum
Authentication Type
Authentication
The Hello Packet
Hello packets are OSPF packet type 1. They are sent periodically on all interfaces, including virtual
links, in order to establish and maintain neighbor relationships. In addition, Hello Packets are
multicast on those physical networks having a multicast or broadcast capability, enabling dynamic
discovery of neighboring routers.
All routers connected to a common network must agree on certain parameters such as the Network
Mask, the Hello Interval, and the Router Dead Interval. These parameters are included in hello packets,
so that differences can inhibit the forming of neighbor relationships. A detailed explanation of the
receive processing for Hello packets, so that differences can inhibit the forming of neighbor
relationships.
Description
The OSPF version number
The OSPF packet type. The OSPF packet types
are as follows:
Type Description
1 Hello
2 Database Description
3 Link-State Request
4 Link-State Update
5 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
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
authentication field.
The type of authentication to be used for the
packet.
A 64-bit field used by the authentication scheme.
Table 5-13. OSPF Packet Header
74
DES-3326 Layer 3 Fast Ethernet Switch User's Guide
to. All OSPF packets
except for the
are
64-bit