1. Finish Monday’s Lecture (Lecture 12) Roll out Project 2 Go over Exam 2
Today’s Agenda
Finish Monday’s Lecture (Lecture 12)
Roll out Project 2
Go over Exam 2
Dr. Clincy

2. A routing example
Router R1 receives 500 packets for destination how does Router R1 uses it’s routing table ???
Dr. Clincy

3. Mask Dest. Next Hop I. m0 m2 m1 m0 m0 m0 m0
U case
UGH case
UG case
the router applies the masks to the destination address until a match with the second column
Direct delivery
&  no match
&  no match
&  no match
Dr. Clincy

4. Mask Dest. Next Hop I. m0 m2 m1 m0 m0 m0 m0
U case
UGH case
UG case
Host-specific
&  no match
Network-specific
&  match
Router stops when match is made
Dr. Clincy

5. Example 2 Make the routing table for router R1 in the Figure U UG
Mask Destination Next Hop I. m0 m1 m1 m0 U UG
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6. STRUCTURE OF A ROUTER
We represent a router as a black box that accepts incoming packets from one of the input ports (interfaces), uses a routing table to find the departing output port, and sends the packet from this output port.
The topics discussed in this section include:
Components
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7. Router components
Performs layer 1 and 2 functions: signal to bits, packet decapsulated from frame, error control performed on bits, buffers packets before going to the switching fabric
This is where delay is incurred
Performs layer 1 and 2 functions: bits to signal, packet encapsulated into frame, error control overhead added
Dr. Clincy

8. Crossbar Switching Fabric
Cross Point
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9. A banyan switch Uses a binary string to route across the switch
Example
Given a packet came in on port 1 and needed to go out of port 6, the binary string of 110 will be used – explain this
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10. Project 2 Rollout
This project will explore some of the most useful commands in the network administrator's toolkit: ipconfig, ping, traceroute, and whois (nslookup).
Already posted on your website
Due Date: March 27, pm
Upload to D2L
Dr. Clincy

11. CS4622 Exam 2 Results Grading Scaled Used:
Average Score = 30 (Average Grade = 75)
Score SD = 14
Grading Scaled Used:
67-53 A-grade (2 students)
52-38 B-grade (8 students)
37-23 C-grade (12 students)
D-grade (12 students)
F-grade (1 student)
In getting your grade logged, be sure and pass back the exam after we go over them
Dr. Clincy 11