Lab 15a: Configuring Voice over Frame Relay-Part I

 <  Free Open Study  >  

Lab 13: Configuring Frame Relay Networks and Controlling Frame Relay ARP ”Part II

Lab Walkthrough

Attach the four routers in a back-to-back manner to the Frame Relay network cloud. Use V.35 cables or CSU/DSUs with crossover cables to connect the routers to the Frame Relay switch. Create the four LANs by the use of switches or hubs/MAUs.

When the physical connections are complete, assign IP addresses to all LAN interfaces, as depicted in Figure 5-7. Be sure that you can ping the router's local LAN interface before moving on.

Begin with the sv_lair router, where you can use subinterfaces. Because the scotts_ house, mini_me, and sv_lair routers all have an interface on the same IP subnet, you must create a multipoint interface on sv_lair to accommodate them. There is an additional IP subnet between the sv_lair router and the starbucks_90210 router. For this subnet, you will create an additional point-to-point interface on the Serial 0 interface. With this in mind, you can begin the four-step process for configuring Frame Relay.

First, you define Frame Relay encapsulation on the Serial 0 interface through the encapsulation frame-relay interface command. When the encapsulation is entered, you can define the subinterfaces. You need to configure one as a multipoint and one as a point-to-point subinterface, as previously mentioned. Example 5-20 demonstrates the configuration of Step 1 on the sv_lair router.

Example 5-20 Configuring Frame Encapsulation and Subinterfaces
 sv_lair(config)#  int s0  sv_lair(config-if)#  encapsulation frame-relay  sv_lair(config-if)#  exit  sv_lair(config)#  int s0.1 multipoint  sv_lair(config-subif)#  exit  sv_lair(config)#  int s0.2 point-to-point  sv_lair(config-subif)#  ^Z  sv_lair# 

The next step in configuring Frame Relay is to set the LMI type. In this case, the LMI type is Cisco, and you are using LMI autosense, so there is no need to do any additional configuration for Step 2. This applies to all the routers in the network.

Step 3 requires the specification of dynamic or static address mapping. The EIF will deploy both kinds of addressing. The sv_lair router uses a multipoint network on interface s0.1, which requires static mapping. You will need one frame-relay map statement per protocol per destination site. One frame-relay map statement will point to IP address 10.10.1.10 on DLCI 110, while the other will point to IP address 10.10.1.11 on DLCI 120. Example 5-21 shows the configuration necessary to accomplish this.

Example 5-21 Configuring the Multipoint Interface
 sv_lair(config)#  int s0.1  sv_lair(config-subif)#  ip address 10.10.1.9 255.255.255.248  sv_lair(config-subif)#  frame-relay map ip 10.10.1.10 110 broadcast  sv_lair(config-subif)#  frame-relay map ip 10.10.1.11 120 broadcast  sv_lair(config-subif)#  exit  sv_lair(config)#  int s0.2  sv_lair(config-subif)#  ip address 192.168.1.5 255.255.255.252  sv_lair(config-subif)#  frame-relay interface-dlci 130  sv_lair(config-fr-dlci)#  ^Z  

To configure the point-to-point interface, s0.2, use Inverse ARP to resolve the network address. Therefore, the only configuration that you need to make is to add the interface-dlci command. The starbucks_90210 router requires only an encapsulation frame-relay statement and an interface-dlci 131 statement.

Before you can address any protocol-specific issues, you must finish bringing up the Frame Relay network on all sides. Before trying to configure a routing protocol, you want to get the network to the point at which the router can ping all of its local WAN interfaces, as well as its local LAN interfaces.

scotts_house is not allowed to use subinterfaces or the PVC to mini_me. As soon as both sides of the link between scotts_house and mini_me become active, a dynamic PVC is built by Inverse ARP. To prevent this from happening, you need to shut down the link and disable Inverse ARP. You also need to add two frame-relay map statements for IP. They will use the same DLCI but will point to two different IP addresses; basically, they will tell the router to forward all IP traffic out DLCI 111. Example 5-22 lists the configuration for the scotts_house router.

Example 5-22 Configuration of scotts_house
 scotts_house(config)#  interface s0  scotts_house(config-if)#  encapsulation frame-relay   scotts_house(config-if)#    no frame-relay inverse-arp     graphics/u2190.gif    Disables Inverse-ARP    scotts_house(config-if)#    no arp frame-relay      graphics/u2190.gif    Disables ARP   scotts_house(config-if)#  ip address 10.10.1.10 255.255.255.248  scotts_house(config-if)#  frame-relay map ip 10.10.1.9 111 broadcast  scotts_house(config-if)#  frame-relay map ip 10.10.1.11 111 broadcast  

The configuration of mini_me is similar. It requires two frame-relay map statements pointing at IP addresses 10.10.1.9 and 10.10.1.10 out DLCI 121. Example 5-23 demonstrates the configuration of mini_me.

Example 5-23 Configuration of mini_me
 mini_me(config)#  int s0  mini_me(config-if)#  encapsulation frame-relay  mini_me(config-if)#  no frame-relay inverse-arp  mini_me(config-if)#  no arp frame-relay  mini_me(config-if)#  ip address 10.10.1.11 255.255.255.248  mini_me(config-if)#  frame-relay map ip 10.10.1.10 121 broadcast  mini_me(config-if)#  frame-relay map ip 10.10.1.9 121 broadcast  

Perform a show frame-relay map command on scotts_house and mini_me. Verify that there is not a dynamic PVC on DLCI 151 or 150, as shown in Example 5-24.

Example 5-24 Correct show frame-relay map Command Output with No ARP
 scotts_house#  show frame-relay map   Serial0 (up): ip 10.10.1.9 dlci 111(0x6F,0x18F0), static,  broadcast,               CISCO, status defined, active  Serial0 (up): ip 10.10.1.11 dlci 111(0x6F,0x18F0), static,  broadcast,               CISCO, status defined, active scotts_house# 

If your frame-relay map statement looks like Example 5-25, you are using Inverse ARP.

Example 5-25 Incorrect show frame-relay map , Using Inverse ARP
 scotts_house#  show frame-relay map   Serial0 (up): ip 10.10.1.9 dlci 111(0x6F,0x18F0), dynamic,  broadcast,, status defined, active  Serial0 (up): ip 10.10.1.11 dlci 151(0x97,0x2470), dynamic,  broadcast,, status defined, active 

To test your frame-relay map statements, ping the local routers 10.10.1.9, 10.10.1.10, and 10.10.1.11.

Step 4 of the Frame Relay configuration process (the final step), involves addressing any routing protocol-specific issues. Start by configuring EIGRP on all routers, and use 666 as the Autonomous System ID. On the sv_lair and starbucks_90210 routers, you need to add two network statements under EIGRP. The other routers in the network need only the network 10.0.0.0 and the no auto-summary statements. The configuration for sv_lair looks like Example 5-26. For further information on the EIGRP configuration, see Chapter 11, "Hybrid: Enhanced Interior Gateway Routing Protocol (EIGRP)," later in this book.

Example 5-26 EIGRP Configuration for sv_lair and starbucks_90210
  router eigrp 666   network 10.0.0.0   network 192.168.1.0   no auto-summary   !  

The configuration might appear to be complete at this time ”EIGRP neighbors are formed and routes are being exchanged. However, upon close examination of the routing tables of scotts_house and mini_me in Example 5-27, you'll find that sv_lair is not propagating its routes properly. The sv_lair is not forwarding scotts_house routes to mini_me, and it is not forwarding mini_me routes to scotts_house. But sv_lair is forwarding starbucks_90120 routes and its local routes to scotts_house and mini_me.

Example 5-27 Examining the Routing Tables
 scotts_house#  show ip route  Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP        D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area        N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2        E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP        i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default        U - per-user static route, o - ODR        T - traffic engineered route Gateway of last resort is not set      10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks  D       10.10.2.0/24 [90/2195456] via 10.10.1.9, 00:53:29, Serial0  C       10.10.3.0/24 is directly connected, TokenRing0  D       10.10.6.0/24 [90/2707456] via 10.10.1.9, 00:52:27, Serial0  C       10.10.1.8/29 is directly connected, Serial0      192.168.1.0/30 is subnetted, 1 subnets D       192.168.1.4 [90/2681856] via 10.10.1.9, 00:53:29, Serial0 scotts_house# <<<<<no 10.10.5.0 subnet>>>>> ________________________________________________________________ mini_me#  show ip route  Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP        D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area        N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2        E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP        i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default        U - per-user static route, o - ODR        T - traffic engineered route Gateway of last resort is not set      10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks  D       10.10.2.0/24 [90/2195456] via 10.10.1.9, 00:53:38, Serial0  C       10.10.5.0/24 is directly connected, Ethernet0  D       10.10.6.0/24 [90/2707456] via 10.10.1.9, 00:52:37, Serial0  C       10.10.1.8/29 is directly connected, Serial0      192.168.1.0/30 is subnetted, 1 subnets  D       192.168.1.4 [90/2681856] via 10.10.1.9, 00:53:38, Serial0  mini_me# <<<<<no 10.10.3.0 route>>>>>> ________________________________________________________________ sv_lair#  show ip route  Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP        D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area        N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2        E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP        i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate default        U - per-user static route, o - ODR Gateway of last resort is not set      10.0.0.0/8 is variably subnetted, 5 subnets, 2 masks C       10.10.2.0/24 is directly connected, Ethernet0  D       10.10.3.0/24 [90/2185984] via 10.10.1.10, 00:53:10, Serial0.1   D       10.10.5.0/24 [90/2195456] via 10.10.1.11, 00:53:10, Serial0.1   D       10.10.6.0/24 [90/2195456] via 192.168.1.6, 00:52:08, Serial0.2  C       10.10.1.8/29 is directly connected, Serial0.1      192.168.1.0/30 is subnetted, 1 subnets C       192.168.1.4 is directly connected, Serial0.2 sv_lair# <<<<<all routes present>>>>> 

If you haven't guessed it, the reason for this is because of split horizon. Remember, the rule: A route will not be forwarded back out the same interface or subinterface on which it was received. To resolve this issue, disable split horizon for EIGRP on the sv_lair router. This is accomplished by adding the following command under the s0.1 interface on sv_lair:

 sv_lair(config-subif)#  no ip split-horizon eigrp 666  

Example 5-28 lists the routing table of scotts_house after the change. Notice now that the 10.10.5.0 route appears.

Example 5-28 show ip route Command Output on the scotts_house Router After Disabling Split Horizon
 scotts_house#  show ip route  <<<text omitted>>> Gateway of last resort is not set      10.0.0.0/8 is variably subnetted, 5 subnets, 2 masks D       10.10.2.0/24 [90/2195456] via 10.10.1.9, 00:00:09, Serial0 C       10.10.3.0/24 is directly connected, TokenRing0  D       10.10.5.0/24 [90/2707456] via 10.10.1.9, 00:00:09, Serial0  D       10.10.6.0/24 [90/2707456] via 10.10.1.9, 00:00:09, Serial0 C       10.10.1.8/29 is directly connected, Serial0      192.168.1.0/30 is subnetted, 1 subnets D       192.168.1.4 [90/2681856] via 10.10.1.9, 00:00:09, Serial0 scotts_house# 

Another command that will help verify whether EIGRP is working properly is the show ip eigrp neighbor command. Performing this command on the sv_lair router, you can see three EIGRP neighbors, one for each remote site. Example 5-29 illustrates the output of this command. Chapter 11 discusses this command and EIGRP neighbors in greater detail.

Example 5-29 show ip eigrp neighbor Command Output
 sv_lair#  show ip eigrp neighbors  IP-EIGRP neighbors for process 666 H   Address                 Interface   Hold Uptime   SRTT   RTO  Q  Seq                                         (sec)         (ms)       Cnt Num 0   192.168.1.6             Se0.2        128 00:04:34   32   200  0  8 2   10.10.1.10              Se0.1        179 00:08:19   33   200  0  7 1   10.10.1.11              Se0.1        161 00:08:54   24   200  0  7 sv_lair# 

Example 5-30 lists the relevant portions of all router configurations for this lab.

Example 5-30 Complete Configuration Listings
  hostname sv_lair   !   interface Ethernet0   ip address 10.10.2.1 255.255.255.0   media-type 10BaseT   !   <<<text omitted>>>   !   interface Serial0   no ip address   encapsulation frame-relay   no ip mroute-cache   !   interface Serial0.1 multipoint   ip address 10.10.1.9 255.255.255.248   no ip split-horizon eigrp 666   frame-relay map ip 10.10.1.10 110 broadcast   frame-relay map ip 10.10.1.11 120 broadcast   !   interface Serial0.2 point-to-point   ip address 192.168.1.5 255.255.255.252   frame-relay interface-dlci 130   !   <<<text omitted>>>   !   router eigrp 666   network 10.0.0.0   network 192.168.1.0   no auto-summary   !  ________________________________________________________________  hostname scotts_house   !   ip subnet-zero   !   interface Serial0   ip address 10.10.1.10 255.255.255.248   no ip directed-broadcast   encapsulation frame-relay   no ip mroute-cache   no arp frame-relay   frame-relay map ip 10.10.1.9 111 broadcast   frame-relay map ip 10.10.1.11 111 broadcast   no frame-relay inverse-arp   !   interface TokenRing0   ip address 10.10.3.3 255.255.255.0   no ip directed-broadcast   ring-speed 16   !   router eigrp 666   network 10.0.0.0  ________________________________________________________________  hostname mini_me   !   ip subnet-zero   !   interface Ethernet0   ip address 10.10.5.5 255.255.255.0   no ip directed-broadcast   !   interface Serial0   ip address 10.10.1.11 255.255.255.248   no ip directed-broadcast   encapsulation frame-relay   no ip mroute-cache   no arp frame-relay   frame-relay map ip 10.10.1.9 121 broadcast   frame-relay map ip 10.10.1.10 121 broadcast   no frame-relay inverse-arp   !   interface Serial1   no ip address   no ip directed-broadcast   shutdown   !   interface BRI0   no ip address   no ip directed-broadcast   shutdown   !   router eigrp 666   network 10.0.0.0  ________________________________________________________________  hostname mini_me   !   ip subnet-zero   !   interface Ethernet0   ip address 10.10.5.5 255.255.255.0   no ip directed-broadcast   !   interface Serial0   ip address 10.10.1.11 255.255.255.248   no ip directed-broadcast   encapsulation frame-relay   no ip mroute-cache   no arp frame-relay   frame-relay map ip 10.10.1.9 121 broadcast   frame-relay map ip 10.10.1.10 121 broadcast   no frame-relay inverse-arp   !   router eigrp 666   network 10.0.0.0  ________________________________________________________________  hostname starbucks_90210   !   interface Ethernet0   ip address 10.10.6.6 255.255.255.0   !   interface Serial0   ip address 192.168.1.6 255.255.255.252   encapsulation frame-relay   frame-relay interface-dlci 131   !   <<text omitted>>>   !   router eigrp 666   network 10.0.0.0   network 192.168.1.0   no auto-summary  
 <  Free Open Study  >  


CCIE Practical Studies, Volume I
CCIE Practical Studies, Volume I
ISBN: 1587200023
EAN: 2147483647
Year: 2001
Pages: 283
Authors: Karl Solie

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net