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Chapter 4
OSPF Areas
Here is a packet decode of an Explicit acknowledgement:
IP Header - Internet Protocol Datagram
Version: 4
Header Length: 5
Precedence: 6
Type of Service: %000
Unused: %00
Total Length: 84
Identifier: 1285
Fragmentation Flags: %000
Fragment Offset: 0
Time To Live: 1
IP Type: 0x59 OSPF (Hex value for protocol
number)
Header Checksum: 0x8dda
Source IP Address: 131.31.194.140
Dest. IP Address: 224.0.0.6
No Internet Datagram Options
OSPF - Open Shortest Path First Routing Protocol
Version: 2
Type: 5 Link State Acknowledgement
Packet Length: 64
Router IP Address: 142.42.193.1
Area ID: 1
Checksum: 0x6699
Authentication Type: 0 No Authentication
Authentication Data:
........ 00 00 00 00 00 00 00 00
Link State Advertisement Header
Age: 3600 seconds
Options: %00100010
No AS External Link State Advertisements
Type: 3 Summary Link (IP Network)
ID: 0x90fb6400
Advertising Router: 153.53.193.1
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