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This chapter is from the book

Section 1: Bridging and Switching (15 Points)

Section 1.1: Frame Relay Configuration (6 points)

  • Configure the Frame Relay portion of the network as shown in Figure 1-8; ensure that DLCIs 110 and 104 between R1-R6 are not used.

The question clearly states that DLCIs 110 and 104 are not to be used; you must, therefore, disable inverse-arp on the routers. It is good practice to ensure that all routers do not rely on inverse-arp so if you have configured no frame-relay inverse-arp under routers R1,R4 and R6 serial interfaces 0/0, you have scored 2 points.

If you experience difficulties and can not clear any dynamic map entries, reload your routers to remove these, a drastic measure but every point counts.

  • The routers are to be on the same subnet and should be configured with subinterfaces.

R4 will need to be a multipoint subinterface to accommodate both R1 and R6 on the same subnet; R1 and R6 only have PVCs to R4, hence, they will require point-to-point subinterfaces. R4 will require manual frame-relay map statements pointing to both R1 and R6 as inverse arp is disabled. The maps require the broadcast keyword as RIP will multicast the routing updates over the PVCs. It should be apparent that when RIP is run over a multipoint interface, split horizon will be enabled by default and routing updates from R6 into R1 will never be propagated by the hub router R4 because of the rule of not advertising a network that was received on the same interface; R4 will, therefore, require no ip split-horizon configured under its Frame Relay interface. If you have configured all items correctly as in Example 1-1 through Example 1-3, you have scored 4 points, unfortunately no marks if you have omitted anything.

NOTE

For clarity only, the required configuration details will be listed to answer the specific questions instead of full final configurations.

Example 1-1 R4 Initial Frame Relay Solution Configuration

interface Serial0/0
 no ip address
 encapsulation frame-relay
 no frame-relay inverse-arp
!
interface Serial0/0.1 multipoint
 ip address 10.100.100.3 255.255.255.240
 no ip split-horizon
 frame-relay map ip 10.100.100.1 100 broadcast
 frame-relay map ip 10.100.100.2 102 broadcast

Example 1-2 R1 Initial Frame Relay Solution Configuration

interface Serial0/1
 no ip address
 encapsulation frame-relay
 no frame-relay inverse-arp
!
interface Serial0/1.101 point-to-point
 ip address 10.100.100.1 255.255.255.240 frame-relay interface-dlci 101

Example 1-3 R6 Initial Frame Relay Solution Configuration

interface Serial5/0
 no ip address
 encapsulation frame-relay
 no frame-relay inverse-arp
!
interface Serial5/0.103 point-to-point
 ip address 10.100.100.2 255.255.255.240
 frame-relay interface-dlci 103

Section 1.2: 3550 LAN Switch Configuration (6 Points)

  • Configure VLAN numbers, VLAN names, and port assignment as per the topology diagram as shown in Figure 1-10.

The switch in this instance is isolated but you can still use the default mode of VTP Server. From the VLAN database, add the required VLANs and name them accordingly; you should note that you can not change the VLAN name of VLAN1. You must ensure that the port speed and duplex is fixed to 100 Mbps and full duplex, if your routers support this; leaving your ports in auto mode could cause connectivity problems. If you have configured these items correctly as in Example 1-4, you have scored 2 points.

Example 1-4 3550 Switch1 Initial Configuration

Switch1#vlan database
Switch1(vlan)#vlan 2 name VLAN2 
VLAN 2 modified:
    Name: VLAN2
Switch1(vlan)#vlan 3 name VLAN3 
VLAN 3 modified:
    Name: VLAN3
Switch1(vlan)#vlan 4 name VLAN4 
VLAN 4 modified:
    Name: VLAN4
Switch1(vlan)#vlan 5 name VLAN5 
VLAN 5 modified:
    Name: VLAN5
Switch1(vlan)#exit
APPLY completed.
Exiting....
interface FastEthernet0/1
 switchport access vlan 2
 switchport mode access
 no ip address
 duplex full
 speed 100
!
interface FastEthernet0/2
 switchport mode access
 no ip address
 duplex full
 speed 100
!
interface FastEthernet0/3
 switchport mode access
 no ip address
 duplex full
 speed 100
!
interface FastEthernet0/4
 switchport access vlan 3
 switchport mode access
 no ip address
 duplex full
 speed 100
!
interface FastEthernet0/5
 switchport access vlan 4
 switchport mode access
 no ip address
 duplex full
 speed 100
!
interface FastEthernet0/6
 switchport access vlan 2
 switchport mode access
 no ip address
 duplex full
 speed 100
!
interface FastEthernet0/7
 switchport access vlan 5
 switchport mode access
 no ip address
 duplex full
 speed 100
!
interface FastEthernet0/8
 switchport access vlan 2
 switchport mode access
 no ip address
 duplex full
 speed 100
!
interface FastEthernet0/9
 switchport access vlan 5
 switchport mode access
 no ip address
 duplex full
 speed 100

NOTE

The VLAN configuration is completed under vlan database.

  • There is to be a host connected on interface 0/16 in the future; the network administrator requires that this host is authenticated by a radius server before access to the switch is granted. The radius server is to be located on the IP address 172.16.100.100 with the key radius14.

This question calls for 802.1X Authentication before a port is granted access to the switch and network. If configured correctly as in Example 1-5, you have scored 3 points.

Example 1-5 802.1X Switch Configuration

aaa new-model
aaa authentication dot1x default group radius
!
interface FastEthernet0/16
 
 switchport mode access
 no ip address
 dot1x port-control auto
!
radius-server host 172.16.100.100 auth-port 1812 key radius14

  • Ensure the switch is reachable via Telnet to the IP address of 10.80.80.8/24.

Configure VLAN2 with the IP address of 10.80.80.8 255.255.255.0. The switch will also need a default-gateway configured; you could use 10.80.80.2 or 10.80.80.1 here. The previous question requires that you enable AAA. Enabling AAA prompts you for a username when you telnet to the switch from one of your routers. To ensure typical access to the preconfigured line and to ensure that the enable password is used for telnet access to the switch, you should add the aaa authentication login default enable authentication configuration onto the switch.

Example 1-6 Switch1 Management IP Configuration

aaa authentication login default enable 
enable password cisco 
!
interface Vlan2
 ip address 10.80.80.8 255.255.255.0
!
ip default-gateway 10.80.80.2
!
line con 0
 password cisco
line vty 0 15
 password cisco

Section 1.3: ATM Configuration (3 Points)

  • Configure the ATM network as shown in Figure 1-12.

  • Use a subinterface on R6 for the ATM matching the VCI number and ensure the latest method of PVC configuration is used on this router. For R5 ATM, use the physical interface and legacy PVC configuration; after you have configured your Layer 2 information, you may then add the Layer 3 addresses.

  • Do not rely on inverse ARP.

R6 requires a point-to-point subinterface named ATM1/0.99 with the PVC details configured under the separate PVC; R5 requires the legacy style with the map-list to achieve the PVC connectivity in this back-to-back configuration. The map-list, ip 10.99.99.1 atm-vc 1 broadcast, and protocol ip 10.99.99.2 commands ensure that inverse-arp is not relied upon.

You can use whichever encapsulation suits the three tasks in Section 1.3 as it has not been defined which type must be used.

If you have successfully configured all items as in Example 1-7 and Example 1-8, you have scored 3 points.

Example 1-7 R6 ATM Configuration and Map Verification

interface ATM1/0
 no ip address
 no atm ilmi-keepalive
!
interface ATM1/0.99 point-to-point
 ip address 10.99.99.1 255.255.255.248
pvc 0/99
  protocol ip 10.99.99.2  broadcast 
  encapsulation aal5snap
R6#show atm map
Map list ATM1/0.99pvc1 : PERMANENT
ip 10.99.99.2 maps to VC 1, VPI 0, VCI 99, ATM1/0.99
        , broadcast

Example 1-8 R6 ATM Configuration and Map Verification

interface ATM3/0
 ip address 10.99.99.2 255.255.255.248
 map-group atm
 atm pvc 1 0 99 aal5snap
 no atm ilmi-keepalive
!
map-list atm
 ip 10.99.99.1 atm-vc 1 broadcast

R5#show atm map
Map list atm : PERMANENT
ip 10.99.99.1 maps to VC 1
        , broadcast

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