Section 7: IOS and IP Features (14 Points)

• Ensure that when pinging to destination 10.80.80.255 from R3 that R1, R6, R8, and Switch1 reply.

By default, the broadcast ping will be terminated by R1 but it will itself respond to the ping. By configuring R1 with the command ip directed-broadcast on Fast Ethernet0/0, R1 will then forward the ping to the whole destination subnet, which will result in R6, R8, and Switch1 also replying to the ping.

Example 2-72 shows verification of a broadcast ping to 10.80.80.255 initiated from R3 with replies received from R1, R6, R8, and Switch1.

If you have configured this correctly, you have scored 3 points.

Example 2-72. R3 Broadcast Ping Verification

 R3#debug ip icmp ICMP packet debugging is on R3#ping 10.80.80.255 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.80.80.255, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/8 ms R3# 01:35:39: ICMP: echo reply rcvd, src 10.90.90.2, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.90.90.2, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.80.80.2, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.80.80.3, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.80.80.2, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.80.80.8, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.80.80.3, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.90.90.2, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.80.80.2, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.80.80.8, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.80.80.3, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.90.90.2, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.80.80.2, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.80.80.8, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.80.80.3, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.90.90.2, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.80.80.2, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.80.80.8, dst 172.16.0.2 01:35:39: ICMP: echo reply rcvd, src 10.80.80.3, dst 172.16.0.2 

• R7 used to belong to VLAN4 but has been moved to VLAN5 and is now unreachable. Configure the network in such a way that communication can still exist between VLAN4 and just the Ethernet address of R7 without modifying the IP address of R7.

You need to configure LAM on R6 with an access group that only permits host 10.50.50.2. You have to redistribute mobile into OSPF on R6 so your network learns where host 10.50.50.2 is by the more specific host route that R6 will generate. R7 will now be able to communicate only with its home subnet VLAN4. Remember that R7 does not have routing capability at this point. If you have configured this correctly as shown in Example 2-73, you have scored 4 points.

Example 2-73. R6 LAM Configuration and Verification

 interface FastEthernet4/0  ip address 10.60.60.1 255.255.255.248  ip mobile arp access-group 50 ! router ospf 30 redistribute mobile subnets default-metric 4000 ! access-list 50 permit 10.50.50.2 R7#ping 10.50.50.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.50.50.1, timeout is 2 seconds: .!!!! Success rate is 80 percent (4/5), round-trip min/avg/max = 1/3/4 ms 

• Allow R7 to ping the IP addresses assigned to Loopback0 on R1, R4, R5, R6, and R8; do not assign any static, dynamic, or policy routes to achieve this. Perform configuration only on R7.

As mentioned in the previous question, R7 does not have routing capability so you will have to manipulate the router to perform this connectivity. As you cannot use any form of routing to achieve this, you must forward the traffic for the destinations to R6, which has full visibility of the entire network. If you look at the ARP cache of R7, you will find that it already has an ARP entry for 10.50.50.1, which is, in fact, that of R6. Setting up static ARP entries in R7 for the remote destinations pointing to the MAC address of R6 should do the trick; however, it actually requires one further piece of configuration to make this work. As the remote networks are all in different IP subnets to that of R7 Fast Ethernet0/0, the static mappings will not work. By adding a secondary address on R7, which covers all subnets (that is, 10.0.0.1/8), you will find you now have full connectivity to the remote destinations. If you have configured this correctly as shown in Example 2-74 you have scored 5 points. Example 2-75, shows R7 ARP table and ping test results.

Example 2-74. R7 LAM Configuration

 interface FastEthernet0/0 ip address 10.0.0.1 255.0.0.0 secondary ip address 10.50.50.2 255.255.255.248 speed 100 full-duplex ! arp 10.8.8.8 0001.9799.9870 ARPA arp 10.1.1.1 0001.9799.9870 ARPA arp 10.6.6.6 0001.9799.9870 ARPA arp 10.4.4.4 0001.9799.9870 ARPA arp 10.5.5.5 0001.9799.9870 ARPA 

Example 2-75. R7 LAM Testing

 R7#sh arp Protocol  Address          Age (min)  Hardware Addr   Type   Interface Internet  10.8.8.8                -   0001.9799.9870  ARPA Internet  10.50.50.2              -   0008.a3d1.9c20  ARPA   FastEthernet0/0 Internet  10.50.50.1              0   0001.9799.9870  ARPA   FastEthernet0/0 Internet  10.0.0.1                -   0008.a3d1.9c20  ARPA   FastEthernet0/0 Internet  10.1.1.1                -   0001.9799.9870  ARPA Internet  10.6.6.6                -   0001.9799.9870  ARPA Internet  10.4.4.4                -   0001.9799.9870  ARPA Internet  10.5.5.5                -   0001.9799.9870  ARPA R7# R7#ping 10.1.1.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/8 ms R7#ping 10.4.4.4 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.4.4.4, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/8 ms R7#ping 10.5.5.5 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.5.5.5, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms R7#ping 10.6.6.6 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.6.6.6, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms R7#ping 10.8.8.8 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.8.8.8, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms R7#ping 10.50.50.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.50.50.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 1/3/4 ms 

• Configure R4 so that if R1 and R6 both advertised VLAN2 within OSPF in the future that R4 would be able to load share to this destination across both Frame Relay PVCs; do not change the bandwidth statements on your PVCs.

Before R4 would be able to load share for this future advertisement, you must ensure that the metrics for the route are exactly the same. As the network is to be advertised within OSPF and not redistributed with a default-metric cost, the network will be assigned a metric according to the assigned bandwidth statements on the Frame Relay PVCs. As you cannot change the bandwidth statements, you simply adjust the costs on the R4 interfaces to the same value for each PVC. If you have configured this correctly as in Example 2-76, you have scored 2 points. You will not be deducted points if you have not disabled the route caching feature, which is enabled by default.

Example 2-76. R4 Future Load Sharing Configuration

 interface Virtual-Template1  bandwidth 256  ip ospf cost 400 ! interface Virtual-Template2  bandwidth 512  ip ospf cost 400