D-Link TM DES-6500, Manual

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DES-6500 Chassis-based Layer 3 Ethernet Switch Manual
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Router ID The Router ID of the packet’s source.
Area ID
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
Checksum A standard IP checksum that includes all of the packet’s contents except for
the 64-bit authentication field.
Authentication
Type
The type of authentication to be used for the packet.
Authentication A 64-bit field used by the authentication scheme.
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 the hello packets, so that differences can inhibit
the forming of neighbor relationships. A detailed explanation of the receive process for Hello packets is necessary so that
differences can inhibit the forming of neighbor relationships.
The format of the Hello packet is shown below:
Hello Packet
1
Packet Length
Router ID
Area ID
Version No.
Checksum Authentication Type
Authentication
Authentication
Network Mask
Hello Interval
Options Router Priority
Router Dead Interval
Designated Router
Backup Designated Router
Neighbor
Figure 6- 118. Hello Packet