This lab is based on Lab 4, part 7 on pages 160-164 of the textbook. You will need to refer to the textbook to understand this lab.

First of all, the routers in our lab do not run BGP, so the PCs in this lab will be the only ones running BGP. The routers (router1 and router2) will be used as OSPF routers, RIP routers, and as hosts. On the router, "ping" works almost the same as on the hosts, and "trace" is equivalent to the traceroute command.

The network setup differs from Figure 4.7 -- use this network diagram instead.

Note that any cable connecting two hubs plugs into the uplink port on exactly ONE of the two hubs -- it doesn't really matter which one. Also note that we are using two hubs so we that may disconnect a wire without resetting the interface of the computer.

Exercise 7(A)

1. Configure the interfaces of router1 and router2 according to the diagram.
2. Configure the interfaces of PC1-PC4 according to the diagram.
3. run OSPF on enp4s0 of PC1 and PC2 and on fa0/0 and fa0/1 of router1, in area 1. Use your experience in parts 5 and 6 of Lab four to do this correctly. Use network 10.0.1.0/24 and network 10.0.2.0/24 for OSPF.

   Run the following commands on each router (PC1, PC2, and router1):

   redistribute connected
   redistribute bgp
   redistribute ospf
   redistribute rip
   

   If supported, also repeat these commands adding the word subnet at the end of each command.

4. run RIP on enp4s0 of PC3 and PC4 and on fa0/0 and fa0/1 of router2. Use your experience in parts 1-4 of Lab four to do this correctly. For RIP, use network 10.0.5.0/24 and network 10.0.6.0/24.

   Repeat the redistribute commands on PC3, PC4, and router2.

5. use ping and traceroute to verify that
   1. each router and PC can reach all the other interfaces within the same autonomous system
   2. each PC can reach the PC it is directly connected to in the other AS, but not any other system in the other AS
   3. the two routers cannot reach any system outside of their AS
6. run wireshark on PC1 enp3s0, with a filter to show or capture only BGP traffic.
7. configure bgp on the four PCs, adapting the instructions in the textbook, beginning with the 4th line on pabe 163 ("router bgp" -- lines before the 4th are needed for CISCO routers, but not for the quagga bgpd). Remember to use the correct AS numbers everywhere.

   Repeat the redistribute commands for the BGP routers on PC1, PC2, PC3, and PC4.

8. Verify that the routing tables of the PCs and routers have routes to the entire network. Verify that you can ping from each router to the other router, and from each of PC1 and PC3 to the router in the other AS.
9. Once everything is working, save the output of wireshark, and save the routing tables of one PC and one router.
10. Run on the four bgpd routers the commands shown on p. 163, item 7, and save the output. That is, "show ip route" (which on the PCs is "route -n" or "netstat -rn"), "show ip bgp", and "show ip bgp paths". Also run (and save the output of) "show ip bgp neighbors".

• answer all the questions on p. 163 in the textbook.

  Be sure to describe what kind of BGP messages you observe, that is, list all of them, and for each, give some idea of what each message does.

Exercise 7(B)

1. Using traceroute, discover whether packets from router1 to router2 go through PC3 or PC4 -- call it PCX (X is 3 or 4). PCX is connected through two hubs to PCY, where Y = X-2 (Y is 1 or 2) -- packets from router1 to router2 also go through PCY, as should be seen on the traceroute.

   Start a ping from PCY to the IP address of the nearer interface of router2. Start wireshark on both PC1 and PC2, capturing packets on both interfaces and displaying OSPF, BGP, and ICMP packets.

2. Disconnect the cable linking the two hubs connecting PCX and PCY.
3. Once the ping is successful again, stop the ping and save the output. Record the time it took for the ping to be successful again.
4. Save the wireshark output on PC1 and PC2. On all four routers repeat and save the output of the commands "show ip route" (which again, on the PCs is "route -n" or "netstat -rn"), "show ip bgp", "show ip bgp paths", and "show ip bgp neighbors". Also save the routing tables on all four PCs and on the two routers.

• how long did it take for PCY to be able to ping router2 again?
• find the BGP and OSPF messages, if any, that allowed PCY to figure out that its route to router2 must go through router1. Describe these messages, and what information each of them carries.

If desired, you may repeat exercise 7B but with the faster timers, as described in the book's exercise 7B. If you do so, compare the time it took for the convergence, and also the rate at which BGP keepalive messages are sent.