Section 4: ISDN (6 Points)


  • Configure ISDN on R3 and R5 using PPP. R3 and R5 should be able to ping each other across the ISDN link.

If you configured this correctly as shown in Example 5-31, you have scored 2 points.

  • Make sure that routing protocols will pass through the ISDN link only when it is up.

If you configured this correctly as shown in Example 5-31, you have scored 2 points.

The key to configuring as requested is to avoid the ISDN to advertise or pass traffic through the link when R5-fa0/0 is up. R3 and R5 are running CLNS, which makes the scenario even more interesting. Remember that your ISDN or BRI interfaces are running IS-IS.

Example 5-31 shows the comfiguration to accomplish the ISDN requirements. To make your ISDN work in some IOS versions, you need to configure the authentication "CHAP" or "PAP"; in other IOS versions, you do not need to configure the authentication to have your ISDN link work (for example, 12.2). IOS Release 12.2 is the assumed version here used to configure an authentication method.

Example 5-31. R3 and R5 ISDN Configuration
 R3#sh run int bri0/0 Building configuration... Current configuration : 340 bytes ! username R5 password 0 cisco ! interface BRI0/0  ip address 160.10.15.3 255.255.255.0  ip router isis  encapsulation ppp  dialer map clns 49.0004.0000.0000.0005.00 name R5 broadcast 2222  dialer map ip 160.10.15.5 name R5 broadcast 2222  dialer-group 1  isdn switch-type basic-ni  isdn spid1 1111  ppp authentication chap  isis circuit-type level-2-only ! ! dialer-list 1 protocol ip permit dialer-list 1 protocol clns permitR3# ________________________________________________________________ R5#sh run int bri0/0 Building configuration... Current configuration : 340 bytes ! username R3 password 0 cisco ! interface BRI0/0  ip address 160.10.15.5 255.255.255.0  ip router isis  encapsulation ppp  dialer map clns 49.0004.0000.0000.0003.00 name R3 broadcast 1111  dialer map ip 160.10.15.3 name R3 broadcast 1111  dialer-group 1  isdn switch-type basic-ni  isdn spid1 2222  ppp authentication chap  isis circuit-type level-2-only end R5# R5#ping 160.10.15.3 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 160.10.15.3, timeout is 2 seconds: 5w1d: %LINK-3-UPDOWN: Interface BRI0/0:1, changed state to up..!!! Success rate is 60 percent (3/5), round-trip min/avg/max = 32/33/36 ms R5# 5w1d: %LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0/0:1, changed state to up 5w1d: %ISDN-6-CONNECT: Interface BRI0/0:1 is now connected to 1111 R3 

  • The ISDN link should pass routing protocols should R5-fa0/0 goes down.

If you configured this correctly as shown in Example 5-32 you have scored 2 points.

Example 5-32. R5 Routing Backup Output
 R5#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, ia - IS-IS inter area        * - candidate default, U - per-user static route, o - ODR        P - periodic downloaded static route Gateway of last resort is not set O E2 196.1.8.0/24 [110/1] via 160.10.37.2, 03:14:25, Serial0/1 O E2 196.1.10.0/24 [110/1] via 160.10.37.2, 03:14:25, Serial0/1      140.200.0.0/24 is subnetted, 1 subnets O E2    140.200.10.0 [110/1] via 160.10.37.2, 03:14:25, Serial0/1      160.10.0.0/16 is variably subnetted, 16 subnets, 3 masks O IA    160.10.32.0/30 [110/128] via 160.10.37.2, 03:14:35, Serial0/1 i L2    160.10.33.0/24 [115/20] via 160.10.22.3, FastEthernet0/0 O       160.10.38.0/24 [110/128] via 160.10.37.2, 03:14:35, Serial0/1 O       160.10.37.2/32 [110/64] via 160.10.37.2, 03:14:36, Serial0/1 O       160.10.37.1/32 [110/128] via 160.10.37.2, 03:14:36, Serial0/1 C       160.10.37.0/24 is directly connected, Serial0/1 O IA    160.10.11.0/24 [110/138] via 160.10.37.2, 03:14:36, Serial0/1 C       160.10.15.0/24 is directly connected, BRI0/0 O       160.10.2.0/24 [110/65] via 160.10.37.2, 03:14:36, Serial0/1 O IA    160.10.3.0/24 [110/129] via 160.10.37.2, 03:14:36, Serial0/1 O       160.10.1.0/24 [110/129] via 160.10.37.2, 03:14:36, Serial0/1 i L2    160.10.6.0/24 [115/20] via 160.10.22.6, FastEthernet0/0 O       160.10.4.0/24 [110/129] via 160.10.37.2, 03:14:36, Serial0/1 C       160.10.5.0/24 is directly connected, Loopback0 C       160.10.25.0/24 is directly connected, FastEthernet0/1 C       160.10.22.0/24 is directly connected, FastEthernet0/0 O E2 196.1.2.0/24 [110/1] via 160.10.37.2, 03:14:26, Serial0/1      130.200.0.0/24 is subnetted, 1 subnets O E2    130.200.10.0 [110/100] via 160.10.37.2, 03:14:26, Serial0/1 O E2 193.118.1.0/24 [110/100] via 160.10.37.2, 03:14:26, Serial0/1 O E2 193.118.3.0/24 [110/100] via 160.10.37.2, 03:14:26, Serial0/1 O E2 193.118.2.0/24 [110/100] via 160.10.37.2, 03:14:26, Serial0/ R5# R5# R5# R5# ! R5-Fa0/0 goes down 5w1d: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down ! CLNS ping fails R5#ping clns 49.0004.0000.0000.0003.00 Type escape sequence to abort. Sending 5, 100-byte CLNS Echos with timeout 2 seconds CLNS: cannot send ECHO. CLNS: cannot send ECHO. CLNS: cannot send ECHO. CLNS: cannot send ECHO. CLNS: cannot send ECHO. Success rate is 0 percent (0/5) R5# R5#ping 160.10.15.3 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 160.10.15.3, timeout is 2 seconds: 5w1d: %LINK-3-UPDOWN: Interface BRI0/0:1, changed state to up..!!! Success rate is 60 percent (3/5), round-trip min/avg/max = 32/33/36 ms R5# 5w1d: %LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0/0:1, changed state to up 5w1d: %ISDN-6-CONNECT: Interface BRI0/0:1 is now connected to 1111 R3 R5# ! Now ISDN link is up R5# R5# R5#ping clns 49.0004.0000.0000.0003.00 Type escape sequence to abort. Sending 5, 100-byte CLNS Echos with timeout 2 seconds !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 36/38/40 ms R5#sh ip ro 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, ia - IS-IS inter area        * - candidate default, U - per-user static route, o - ODR        P - periodic downloaded static route Gateway of last resort is not set O E2 196.1.8.0/24 [110/1] via 160.10.37.2, 03:20:03, Serial0/1 O E2 196.1.10.0/24 [110/1] via 160.10.37.2, 03:20:03, Serial0/1      140.200.0.0/24 is subnetted, 1 subnets O E2    140.200.10.0 [110/1] via 160.10.37.2, 03:20:03, Serial0/1      160.10.0.0/16 is variably subnetted, 17 subnets, 3 masks O IA    160.10.32.0/30 [110/128] via 160.10.37.2, 03:20:13, Serial0/1 i L2    160.10.33.0/24 [115/20] via 160.10.15.3, BRI0/0 O       160.10.38.0/24 [110/128] via 160.10.37.2, 03:20:13, Serial0/1 O       160.10.37.2/32 [110/64] via 160.10.37.2, 03:20:14, Serial0/1 O       160.10.37.1/32 [110/128] via 160.10.37.2, 03:20:14, Serial0/1 C       160.10.37.0/24 is directly connected, Serial0/1 O IA    160.10.11.0/24 [110/138] via 160.10.37.2, 03:20:14, Serial0/1 C       160.10.15.0/24 is directly connected, BRI0/0 C       160.10.15.3/32 is directly connected, BRI0/0 O       160.10.2.0/24 [110/65] via 160.10.37.2, 03:20:18, Serial0/1 O IA    160.10.3.0/24 [110/129] via 160.10.37.2, 03:20:18, Serial0/1 O       160.10.1.0/24 [110/129] via 160.10.37.2, 03:20:18, Serial0/1 i L2    160.10.6.0/24 [115/30] via 160.10.15.3, BRI0/0 O       160.10.4.0/24 [110/129] via 160.10.37.2, 03:20:18, Serial0/1 C       160.10.5.0/24 is directly connected, Loopback0 C       160.10.25.0/24 is directly connected, FastEthernet0/1 i L2    160.10.22.0/24 [115/20] via 160.10.15.3, BRI0/0 O E2 196.1.2.0/24 [110/1] via 160.10.37.2, 03:20:08, Serial0/1      130.200.0.0/24 is subnetted, 1 subnets O E2    130.200.10.0 [110/100] via 160.10.37.2, 03:20:08, Serial0/1 O E2 193.118.1.0/24 [110/100] via 160.10.37.2, 03:20:08, Serial0/1 O E2 193.118.3.0/24 [110/100] via 160.10.37.2, 03:20:08, Serial0/1 O E2 193.118.2.0/24 [110/100] via 160.10.37.2, 03:20:08, Serial0/1 




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

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