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CS716
Advanced Computer Networks
By Dr. Amir Qayyum
1
Lecture No. 22
OSPF Routing Protocol
• Authentication of routing messages
– Encrypted communication between routers
• Additional hierarchy
– Domains are split into areas
– Routers only need to know how to reach every node in
a domain
– Routers need to know how to get to the right area
– Load balancing
• Allows traffic to be distributed over multiple routes
Original ARPANET Metric
• Uniform 56 kbps lines
– Bandwidth equal on every line (hence irrelevant)
– Latency relatively unimportant
• Use queue length as distance (number of packets
waiting to use a link)
Problems
– Uniform bandwidth assumption became invalid