Section 2: IP IGP Protocols (16 Points)


Configure the IP routing as in Figure 3-13 as directed.

Section 2.1: EIGRP (7 Points)

  • Configure EIGRP AS1 as shown in Figure 3-13. Initial loopback interfaces should be advertised within EIGRP for every router running EIGRP.

You should configure EIGRP AS1 on R1-R2-R3. You could just enable EIGRP with a network 10.0.0.0 statement everywhere. But as you can see in Figure 3-13, R1 does not have all its network 10 interfaces included in EIGRP. You will need to configure an inverse mask for the networks you require advertised and included in EIGRP on R1; preferably, configure R2 and R3 in the same manner although you will not loose marks for this in this case. Do not forget to disable auto summarization on all your routers as a matter of good practice even though strictly speaking this is not required on R3. If you have configured this correctly as shown in Example 3-11 through Example 3-13, you have scored 2 points.

Example 3-11. R1 Initial EIGRP Configuration
 router eigrp 1  network 10.1.1.0 0.0.0.15  network 10.90.90.0 0.0.0.15  no auto-summary 

Example 3-12. R2 Initial EIGRP Configuration
 router eigrp 1  network 10.2.2.0 0.0.0.15  network 10.90.90.0 0.0.0.15  network 172.16.0.0  no auto-summary 

Example 3-13. R3 Initial EIGRP Configuration
 router eigrp 1  network 10.3.3.0 0.0.0.15  network 172.16.0.0  no auto-summary 

  • Authenticate routing updates.

As in Lab 2, a question, which will eat into your time, that is also in preparation for a task within the IOS section. To authenticate the EIGRP updates, you need to configure a key chain with appropriate key-string and enable it on the EIGRP interfaces (with exception to the loopbacks). If you configured this correctly as shown in Example 3-14 through Example 3-15, you have scored 2 points.

Example 3-14. R1 Initial EIGRP Authentication Configuration
 key chain Brussels  key 1   key-string Asterix ! interface Serial0/0  ip authentication mode eigrp 1 md5  ip authentication key-chain eigrp 1 Brussels 

Example 3-15. R2 Initial EIGRP Authentication Configuration
 key chain Brussels  key 1   key-string Asterix ! interface FastEthernet0/0  ip authentication mode eigrp 1 md5  ip authentication key-chain eigrp 1 Brussels ! interface Serial0/0  ip authentication mode eigrp 1 md5  ip authentication key-chain eigrp 1 Brussels 

Example 3-16. R3 Initial EIGRP Authentication Configuration
 key chain Brussels  key 1   key-string Asterix ! interface FastEthernet0/0  ip authentication mode eigrp 1 md5  ip authentication key-chain eigrp 1 Brussels 

  • Allow R3 to only receive routing updates from R2 even if a further EIGRP router is added to VLAN1

Versions of Cisco IOS Software prior to Release 12.2.16 had a neighbor command within EIGRP. Subsequent releases do not. Even though you are running authentication, further EIGRP speakers could be added to VLAN1 and configured with the correct authentication; if this happened, R3 would be able to receive routes from them. R3 can selectively receive routes by configuring a distribute-list with the gateway option enabled; this should contain purely R2's Ethernet address within a prefix-list. If you have configured this correctly as shown in Example 3-17, you have scored 3 points.

Example 3-17. R3 EIGRP Gateway Configuration
 router eigrp 1  distribute-list gateway neighbor-R2 in FastEthernet 0/0 ! ip prefix-list neighbor-R2 seq 5 permit 172.16.0.1/32 

Section 2.2: OSPF (5 Points)

  • Configure OSPF as shown in Figure 3-13 with the process on each router as 1. Ensure that all OSPF routers have their loopback interfaces advertised in the same area as that of the Ethernet interface.

You will need to configure OSPF on R1, R2, R4, R5, R6, R7, and R8 ensuring that all OSPF-only routers have their loopback interfaces advertised within their Ethernet assigned areas. This means network 10.1.1.0/28 will be advertised within both EIGRP and OSPF. You will also need to configure a virtual link between R6 and R5 to extend area 0 out to R5 area 5 via area 4. You can manually configure your router ID within OSPF if you choose to even though it will not change within the lab. If you have configured this correctly as shown in Example 3-18 through Example 3-24, then you have scored 2 points.

Example 3-18. R1 Initial OSPF Configuration
 router ospf 30  network 10.1.1.0 0.0.0.15 area 0  network 10.10.10.0 0.0.0.15 area 0  network 10.100.100.0 0.0.0.15 area 0  network 10.80.80.0 0.0.0.255 area 2  network 10.90.90.0 0.0.0.15 area 0 

Example 3-19. R2 Initial OSPF Configuration
 router ospf 1  network 10.90.90.0 0.0.0.15 area 0 

Example 3-20. R4 Initial OSPF Configuration
 router ospf 1  network 10.4.4.0 0.0.0.15 area 1  network 10.10.10.0 0.0.0.15 area 0  network 10.40.40.0 0.0.0.15 area 1  network 10.100.100.0 0.0.0.15 area 0 

Example 3-21. R5 OSPF Configuration
 router ospf 1  router-id 10.5.5.5  area 4 virtual-link 10.6.6.6  network 10.5.5.0 0.0.0.15 area 5  network 10.50.50.0 0.0.0.7 area 5  network 10.99.99.0 0.0.0.7 area 4 

Example 3-22. R6 Initial OSPF Configuration
 router ospf 1  router-id 10.6.6.6  area 4 virtual-link 10.5.5.5  network 10.6.6.0 0.0.0.15 area 6  network 10.60.60.0 0.0.0.7 area 6  network 10.80.80.0 0.0.0.255 area 2  network 10.99.99.0 0.0.0.7 area 4  network 10.100.100.0 0.0.0.15 area 0 

NOTE

R6 loopback network 10.6.6.0/28 can be advertised within either area 2 or 6 because R6 has two Ethernet interfaces, one of which is in area 2 and the other in area 6.


Example 3-23. R7 OSPF Configuration
 router ospf 1  network 10.7.7.0 0.0.0.15 area 6  network 10.60.60.0 0.0.0.7 area 6 

Example 3-24. R8 OSPF Configuration
 router ospf 1  network 10.8.8.0 0.0.0.15 area 2  network 10.80.80.0 0.0.0.255 area 2 

  • Do not use the ip ospf network command over the Frame Relay network.

The Frame Relay network is NBMA; without using the network command and without having broadcast capability within your Frame Relay maps, you will need to statically configure neighbors. You will need to configure neighbor 10.100.100.1 and neighbor 10.100.100.2 under the OSPF process on R4; you could also configure R1 and R6 with neighbor statements pointing to R4 but this could be considered overconfiguration as it is not strictly required to ensure operability. This particular Frame Relay scenario will also introduce a DR (Designated Router), which should be R4 as it is the hub; in fact, because the Router ID being highest, R6 would become the DR if permitted to. The simplest method of ensuring R4 becomes the DR is by not allowing R1 and R6 to enter into the DR negotiations by configuring ip ospf priority 0 under the Frame Relay interfaces of R1 and R6. If you have configured these items correctly as shown in Example 3-25 through Example 3-27, you have scored 2 points.

NOTE

Example 3-25 through Example 3-27 also show the required configuration for the MTU issue, which has previously been discussed in the initial Frame Relay section of the de-brief. Without configuring the command ip ospf mtu-ignore under the physical Frame Relay interfaces on R1 and R6, you will find that your OSPF network will fail over the Frame Relay.


Example 3-25. R1 OSPF Frame Relay and Neighbor Configuration
 interface Serial0/1  ip mtu 950  encapsulation frame-relay  ip ospf priority 0  ip ospf mtu-ignore 

Example 3-26. R4 OSPF Neighbor Configuration
 router ospf 1  neighbor 10.100.100.1  neighbor 10.100.100.2 

Example 3-27. R6 OSPF Frame Relay and Neighbor Configuration
 interface Serial5/0  ip mtu 950  encapsulation frame-relay  ip ospf priority 0  ip ospf mtu-ignore 

  • Ensure that no host routes are propagated throughout the network.

You will need to configure your loopback interfaces on R1, R4, R5, R6, R7, and R8, which are advertised within OSPF with ip ospf-network point-to-point statements to ensure they are advertised with the correct mask as opposed to /32 host routes to your network. You will also need to configure your virtual-template interfaces on R5 and R6 with the command no peer neighbor-route to remove the /32 host routes that are added to the routing table when the PPP links become active over the ATM and on the serial interface connection between R1 and R2.

If you have configured this correctly, you have scored 1 point.

Section 2.3: Redistribution (4 Points)

  • Redistribute OSPF into EIGRP on R2; do not perform mutual redistribution and only allow OPSF routes with a mask greater than 255.255.0.0 into EIGRP.

You are not being requested to perform mutual redistribution here so you are required to redistribute OSPF into EIGRP on R2. To allow only OSPF routes with masks greater than /16, you need to configure a route map and prefix-list accordingly along with a default metric.

You should realize that the majority of your OSPF network will not have visibility of VLAN1 172.16.0.0/16 and R2 loopback0 10.2.2.0/28 as EIGRP has not been redistributed into OSPF. The lab guidelines do state that these networks are exempt from the full IP visibility required between routers and this will become apparent in the BGP section. If you have configured this correctly as shown in Example 3-28, you have scored 4 points.

Example 3-28. R2 OSPF Redistribution Configuration
 router eigrp 1  redistribute ospf 1 route-map eigrp-ospf  default-metric 1000 10 255 1 1500 ! ! ip prefix-list /16 seq 5 permit 0.0.0.0/0 ge 16 ! route-map eigrp-ospf permit 10  match ip address prefix-list /16 




CCIE Routing and Switching Practice Labs
CCIE Routing and Switching Practice Labs
ISBN: 1587051478
EAN: 2147483647
Year: 2006
Pages: 268

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