User manual

xStack DES-3800 Series Layer 3 Stackable Fast Ethernet Managed Switch
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silent router as down.
Designated Router The identity of the DR for this network, in the view of the
advertising router. The DR is identified here by its IP interface
address on the network.
Backup Designated Router The identity of the Backup Designated Router (BDR) for this
network. The BDR is identified here by its IP interface address
on the network. This field is set to 0.0.0.0 if there is no BDR.
Field Description
Neighbor The Router IDs of each router from whom valid Hello packets
have been seen within the Router Dead Interval on the
network.
Database Description Packet
Database Description packets are OSPF packet type 2. These packets are exchanged when an
adjacency is being initialized. They describe the contents of the topological database. Multiple
packets may be used to describe the database. For this purpose, a poll-response procedure is used. One
of the routers is designated to be master, the other a slave. The master seconds Database Description
packets (polls) that are acknowledged by Database Description packets sent by the slave (responses).
The responses are linked to the polls via the packets’ DD sequence numbers.
Database Description Packet
Version No.
2Packet Length
Router ID
Area ID
Authentication Type
Authentication
Authentication
Checksum
Options
DD Sequence No.
Reserved
Reserved
Link-State Advertisement Header ...
IM
MS
Figure 8- 18. Database Description Packet
Field Description
Options The optional capabilities supported by the router.
I - bit The Initial bit. When set to 1, this packet is the first in the sequence
of Database Description packets.
M - bit The More bit. When set to 1, this indicates that more Database
Descripti
on packets will follow