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

A routing example Router R1 receives 500 packets for destination 192.16.7.14 - how does Router R1 uses it’s routing table ??? Dr. Clincy

Mask Dest. Next Hop I. 255.0.0.0 111.0.0.0 -- m0 255.255.255.224 193.14.5.160 - m2 255.255.255.224 193.14.5.192 - m1 ---------------------------------------------------------------------------255.255.255.255 194.17.21.16 111.20.18.14 m0 ---------------------------------------------------------------------------- 255.255.255.0 192.16.7.0 111.15.17.32 m0 255.255.255.0 194.17.21.0 111.20.18.14 m0 0.0.0.0 0.0.0.0 111.30.31.18 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 192.16.7.14 & 255.0.0.0  192.0.0.0 no match 192.16.7.14 & 255.255.255.224  192.16.7.0 no match 192.16.7.14 & 255.255.255.224  192.16.7.0 no match Dr. Clincy

Mask Dest. Next Hop I. 255.0.0.0 111.0.0.0 -- m0 255.255.255.224 193.14.5.160 - m2 255.255.255.224 193.14.5.192 - m1 ---------------------------------------------------------------------------255.255.255.255 194.17.21.16 111.20.18.14 m0 ---------------------------------------------------------------------------- 255.255.255.0 192.16.7.0 111.15.17.32 m0 255.255.255.0 194.17.21.0 111.20.18.14 m0 0.0.0.0 0.0.0.0 111.30.31.18 m0 U case UGH case UG case Host-specific 192.16.7.14 & 255.255.255.255 192.16.7.14 no match Network-specific 192.16.7.14 & 255.255.255.0 192.16.7.0 match Router stops when match is made Dr. Clincy

Example 2 Make the routing table for router R1 in the Figure U UG Mask Destination Next Hop I. 255.255.0.0 134.18.0.0 -- m0 255.255.0.0 129.8.0.0 222.13.16.40 m1 255.255.255.0 220.3.6.0 222.13.16.40 m1 0.0.0.0 0.0.0.0 134.18.5.2 m0 U UG Dr. Clincy

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 Dr. Clincy

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

Crossbar Switching Fabric Cross Point Dr. Clincy

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 Dr. Clincy

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, 2017 5pm Upload to D2L Dr. Clincy

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) 22-8 D-grade (12 students) 7-0 F-grade (1 student) In getting your grade logged, be sure and pass back the exam after we go over them Dr. Clincy 11