| [ LiB ] |   |
Scenarios
This section provides two scenarios of how backup lines can be configured to provide redundancy for primary lines. Each scenario outlines the steps involved in the setup. The results are shown and then verified. Finally, the complete configuration of the routers is shown.
Scenario 10-1: Configuring Dial Backup for Primary Line Failures
In this scenario, Routers R1 and R2 are connected via a serial link. The serial link is the primary link. The two routers are also connected via an ISDN line, which is designated as the backup link. This backup link provides redundancy in case the primary link fails.
The following steps are required to configure dial backup for line failures:
- Step 1. Define the primary interface:
Router(config)#interface type number
- Step 2. While in interface configuration mode on the primary interface, define the backup interface to be used:
Router(config-if)#backup interface type number
- Step 3. Specify how long to wait after the primary link goes down before enabling the backup link:
Router(config-if)#backup delay {enable-delay | never} {disable-delay | never}
NOTE
This assumes that you have already successfully configured both the primary and backup links.
Example 10-1 illustrates the configuration.
Example 10-1. Configuring Dial Backup for Primary Link Failures
R1#config t Enter configuration commands, one per line. End with CNTL/Z. R1(config)#int s0/0 R1(config-if)#backup interface bri0/0 R1(config-if)# 00:39:163208757247: %ISDN-6-LAYER2DOWN: Layer 2 for Interface BRI0/0, TEI 66 changed to down 00:39:158913789952: %ISDN-6-LAYER2DOWN: Layer 2 for Interface BR0/0, TEI 66 changed to down 00:39:37: %LINK-5-CHANGED: Interface BRI0/0, changed state to standby mode R1(config-if)#backup delay 5 10 R1(config-if)#^Z
The commands in Example 10-1 designate BRI0/0 as the backup interface for S0/0. The backup link is set to come up 5 seconds after the primary link goes down and is disabled 10 seconds after the primary link comes back up.
It is noteworthy that the backup interface immediately gets placed in standby mode when the backup interface command is issued.
Example 10-2 shows that the BRI0/0 interface is now in standby mode.
Example 10-2. Backup Interface in Standby Mode
R1#show interface bri0/0 BRI0/0 is standby mode, line protocol is down Hardware is PQUICC BRI with U interface Internet address is 10.0.2.1/24 MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation HDLC, loopback not set Last input 00:05:55, output never, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: weighted fair Output queue: 0/1000/64/0 (size/max total/threshold/drops) Conversations 0/1/16 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 606 packets input, 2497 bytes, 0 no buffer Received 1 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 607 packets output, 2502 bytes, 0 underruns 0 output errors, 0 collisions, 1 interface resets 0 output buffer failures, 0 output buffers swapped out 2 carrier transitions
The process is illustrated in Figure 10-7. The primary link between Routers R1 and R2 fails. The backup ISDN interface is then brought up to restore connectivity.
Figure 10-7. Primary Link Failure Topology
Example 10-3 shows what happens on R1 when a primary line fails.
Example 10-3. Backup Interface Comes Up When the Primary Fails
R1#
02:27:31: %LINK-3-UPDOWN: Interface Serial0/0, changed state to down
02:27:31: %OSPF-5-ADJCHG: Process 111, Nbr 10.0.2.2 on Serial0/0 from FULL to
DOWN, Neighbor Down: Interface down or detached
02:27:32: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed
state to down
02:27:36: %LINK-3-UPDOWN: Interface BRI0/0:1, changed state to down
02:27:36: %LINK-3-UPDOWN: Interface BRI0/0:2, changed state to down
02:27:156792760292: %ISDN-6-LAYER2UP: Layer 2 for Interface BR0/0, TEI 66 changed
to up
02:27:36: %LINK-3-UPDOWN: Interface BRI0/0, changed state to up
02:28:02: %LINK-3-UPDOWN: Interface BRI0/0:1, changed state to up
02:28:03: %LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0/0:1, changed state
to up
02:28:08: %ISDN-6-CONNECT: Interface BRI0/0:1 is now connected to 4082222222
02:28:12: %OSPF-5-ADJCHG: Process 111, Nbr 10.0.2.2 on BRI0/0 from LOADING to
FULL, Loading Done
In Example 10-3, you can see that when the s0/0 link on R1 goes down, the BRI0/0 interface, which is configured as its backup, comes up to take its place. When the BRI0/0 interface comes up, it establishes an OSPF adjacency with R2 so that routing updates can be exchanged.
Running the show interface command on the backup interface tells you that it is now active, as shown in Example 10-4 . Note that it is no longer in standby mode.
Example 10-4. Backup Interface Is Now Active
R1#show interface bri0/0 BRI0/0 is up, line protocol is up (spoofing) Hardware is PQUICC BRI with U interface Internet address is 10.0.2.1/24 MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation HDLC, loopback not set Last input 00:00:00, output never, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: weighted fair Output queue: 0/1000/64/0 (size/max total/threshold/drops) Conversations 0/1/16 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 703 packets input, 2926 bytes, 0 no buffer Received 3 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 704 packets output, 2931 bytes, 0 underruns 0 output errors, 0 collisions, 3 interface resets 0 output buffer failures, 0 output buffers swapped out 5 carrier transitions
When the primary line is restored, the backup again transitions back to standby mode, as shown in Example 10-5. Note in the output of the show ip route command that the remote network 192.168.2.0 /24 is now advertised via the serial link.
The output of the show ip ospf neighbor command, shown in Example 10-5, shows that R2 is visible only via the primary serial link.
Example 10-5. Primary Link Gets Restored
R1# 02:30:03: %LINK-3-UPDOWN: Interface Serial0/0, changed state to up 02:30:04: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed state to up 02:30:13: %ISDN-6-DISCONNECT: Interface BRI0/0:1 disconnected from 4082222222 , call lasted 131 seconds 02:30:13: %LINK-3-UPDOWN: Interface BRI0/0:1, changed state to down 02:30:13: %OSPF-5-ADJCHG: Process 111, Nbr 10.0.2.2 on BRI0/0 from FULL to DOWN, Neighbor Down: Interface down or detached 02:30:55834574848: %ISDN-6-LAYER2DOWN: Layer 2 for Interface BRI0/0, TEI 66 changed to down 02:30:55834574848: %ISDN-6-LAYER2DOWN: Layer 2 for Interface BR0/0, TEI 66 changed to down 02:30:13: %OSPF-5-ADJCHG: Process 111, Nbr 10.0.2.2 on Serial0/0 from LOADING to FULL, Loading Done 02:30:13: %LINK-5-CHANGED: Interface BRI0/0, changed state to standby mode 02:30:14: %LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0/0:1, changed state to down R1# R1# R1#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 10.0.0.0/24 is subnetted, 1 subnets C 10.0.1.0 is directly connected, Serial0/0 C 192.168.1.0/24 is directly connected, FastEthernet0/0 O 192.168.2.0/24 [110/74] via 10.0.1.2, 00:14:57, Serial0/0 R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.0.2.2 1 FULL/ - 00:00:33 10.0.1.2 Serial0/0 R1#
Example 10-6 provides the complete configuration of R1 for backup in the case of a primary link failure.
Example 10-6. R1's Configuration
R1#show running-config Building configuration... Current configuration : 1070 bytes ! version 12.1 hostname R1 ! isdn switch-type basic-net3 ! ! interface FastEthernet0/0 ip address 192.168.1.1 255.255.255.0 no ip redirects speed 100 full-duplex ! interface Serial0/0 backup delay 5 10 backup interface BRI0/0 ip address 10.0.1.1 255.255.255.0 no ip redirects clockrate 512000 ! interface BRI0/0 ip address 10.0.2.1 255.255.255.0 dialer map ip 10.0.2.2 broadcast 4082222222 dialer-group 1 isdn switch-type basic-net3 ! router ospf 111 log-adjacency-changes network 10.0.1.0 0.0.0.255 area 0 network 10.0.2.0 0.0.0.255 area 0 network 192.168.1.0 0.0.0.255 area 0 ip classless dialer-list 1 protocol ip permit end
Example 10-7 provides the complete configuration of R2 for backup in the case of a primary link failure.
Example 10-7. R2's Configuration
R2#show running-config
Building configuration...
Current configuration : 1295 bytes
version 12.1
hostname R2
!
ip subnet-zero
!
isdn switch-type basic-net3
!
interface Ethernet0/0
ip address 192.168.2.1 255.255.255.0
no ip redirects
!
interface Serial0/0
backup delay 5 10
backup interface BRI1/0
ip address 10.0.1.2 255.255.255.0
no ip redirects
no fair-queue
!
interface BRI1/0
ip address 10.0.2.2 255.255.255.0
dialer map ip 10.0.2.1 broadcast 4081111111
dialer-group 1
isdn switch-type basic-net3
!
router ospf 111
log-adjacency-changes
network 10.0.1.0 0.0.0.255 area 0
network 10.0.2.0 0.0.0.255 area 0
network 192.168.2.0 0.0.0.255 area 0
!
ip classless
!
dialer-list 1 protocol ip permit
!
end
Scenario 10-2: Configuring Dial Backup for Load Sharing
In this scenario, Routers R1 and R2 are connected via a serial line that is designated as the primary link. The two routers are also connected via an ISDN line that is the backup link. This backup link is supposed to be activated when the load on the primary line crosses a set threshold.
The following steps are required to configure dial backup to support high loads on the primary link:
- Step 1. Define the primary interface:
Router(config)#interface type number
- Step 2. While in interface configuration mode on the primary interface, define the backup interface to be used:
Router(config-if)#backup interface type number
- Step 3. Specify the traffic load threshold at which the backup link is to be activated:
Router(config-if)#backup load {enable-threshold | never} {disable-load | never}
This assumes that you have already successfully configured both the primary and backup links.
NOTE
Because load is calculated on an interface basis, the backup load command cannot be used on subinterfaces.
Example 10-8 illustrates the configuration.
Example 10-8. Configuring Dial Backup to Support Primary Links
R1#config t Enter configuration commands, one per line. End with CNTL/Z. R1(config)#interface serial0/0 R1(config-if)#backup interface bri0/0 R1(config-if)# 03:03:206158430208: %ISDN-6-LAYER2DOWN: Layer 2 for Interface BRI0/0, TEI 66 changed to down 03:03:206158430208: %ISDN-6-LAYER2DOWN: Layer 2 for Interface BR0/0, TEI 66 changed to down 03:03:48: %LINK-5-CHANGED: Interface BRI0/0, changed state to standby mode R1(config-if)# R1(config-if)# R1(config-if)#backup load 25 20 R1(config-if)#^Z
In Example 10-8, the S0/0 interface is supported by the BRI0/0 interface. Note that BRI0/0 is again placed in standby mode. Also, the backup load command specifies that the BRI 0/0 interface will be activated when the load on the primary link exceeds 25 percent and will be deactivated when the load drops below 20 percent.
Figure 10-8 illustrates how the ISDN interfaces on Routers R1 and R2 are used to provide backup for the primary serial interfaces.
Figure 10-8. Primary Link Support Topology
When the load on the primary link is below the specified threshold, the backup link is in standby mode. On the primary link you can see the configured parameters, as shown in Example 10-9.
Example 10-9. Primary and Backup Interfaces with Low Traffic
R1#show interface s0/0 Serial0/0 is up, line protocol is up Hardware is PowerQUICC Serial Internet address is 10.0.1.1/24 Backup interface BRI0/0, failure delay 0 sec, secondary disable delay 0 sec, kickin load 25%, kickout load 20% MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation HDLC, loopback not set Keepalive set (10 sec) Last input 00:00:06, output 00:00:01, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: weighted fair Output queue: 0/1000/64/0 (size/max total/threshold/drops) Conversations 0/1/256 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 19 packets input, 1913 bytes, 0 no buffer Received 7 broadcasts, 0 runts, 0 giants, 0 throttles 1 input errors, 0 CRC, 1 frame, 0 overrun, 0 ignored, 0 abort 21 packets output, 3143 bytes, 0 underruns 0 output errors, 0 collisions, 2 interface resets 0 output buffer failures, 0 output buffers swapped out 0 carrier transitions DCD=up DSR=up DTR=up RTS=up CTS=up R1#show interface bri0/0 BRI0/0 is standby mode, line protocol is down Hardware is PQUICC BRI with U interface Internet address is 10.0.2.1/24 MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation HDLC, loopback not set Last input never, output never, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: weighted fair Output queue: 0/1000/64/0 (size/max total/threshold/drops) Conversations 0/0/16 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 0 packets input, 0 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 0 packets output, 0 bytes, 0 underruns 0 output errors, 0 collisions, 4 interface resets 0 output buffer failures, 0 output buffers swapped out 0 carrier transitions
When the load on the primary link exceeds the configured threshold, the backup interface is brought into action, as shown in Example 10-10.
Example 10-10. Backup Interface Is Brought Up
R1#
00:08:00: %LINK-3-UPDOWN: Interface BRI0/0:1, changed state to down
00:08:00: %LINK-3-UPDOWN: Interface BRI0/0:2, changed state to down
00:08:00: %LINK-3-UPDOWN: Interface BRI0/0, changed state to up
00:08:4294967295: %ISDN-6-LAYER2UP: Layer 2 for Interface BR0/0, TEI 66 changed
to up
00:08:01: %LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0/0:1, changed state
to down
00:08:01: %LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0/0:2, changed state
to down
R1#
Example 10-11 shows that the load on the primary link has exceeded the specified threshold. Also, when you look at the backup link, you can see that it is now up.
Example 10-11. Primary and Backup Interfaces When the Load Threshold Is Exceeded
R1#show interface s0/0 Serial0/0 is up, line protocol is up Hardware is PowerQUICC Serial Internet address is 10.0.1.1/24 Backup interface BRI0/0, failure delay 0 sec, secondary disable delay 0 sec, kickin load 25%, kickout load 20% MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, reliability 255/255, txload 64/255, rxload 1/255 Encapsulation HDLC, loopback not set Keepalive set (10 sec) Last input 00:00:00, output 00:00:00, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 148 Queueing strategy: weighted fair Output queue: 63/1000/64/148 (size/max total/threshold/drops) Conversations 1/2/256 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 392000 bits/sec, 426 packets/sec 124 packets input, 8885 bytes, 0 no buffer Received 63 broadcasts, 0 runts, 0 giants, 0 throttles 1 input errors, 0 CRC, 1 frame, 0 overrun, 0 ignored, 0 abort 215234 packets output, 24533109 bytes, 0 underruns 0 output errors, 0 collisions, 2 interface resets 0 output buffer failures, 0 output buffers swapped out 0 carrier transitions DCD=up DSR=up DTR=up RTS=up CTS=up R1#show interface bri0/0 BRI0/0 is up, line protocol is up (spoofing) Hardware is PQUICC BRI with U interface Internet address is 10.0.2.1/24 MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation HDLC, loopback not set Last input 00:00:00, output never, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: weighted fair Output queue: 0/1000/64/0 (size/max total/threshold/drops) Conversations 0/1/16 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 20 packets input, 99 bytes, 0 no buffer Received 1 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 22 packets output, 139 bytes, 0 underruns 0 output errors, 0 collisions, 5 interface resets 0 output buffer failures, 0 output buffers swapped out 1 carrier transitions
When the load drops below the specified disable load, the backup interface is again put back in standby mode, as shown in Example 10-12.
Example 10-12. Backup Interface Is Put Back in Standby Mode
R1# 00:11:240518168575: %ISDN-6-LAYER2DOWN: Layer 2 for Interface BRI0/0, TEI 66 changed to down 00:11:236223201280: %ISDN-6-LAYER2DOWN: Layer 2 for Interface BR0/0, TEI 66 changed to down 00:11:55: %LINK-5-CHANGED: Interface BRI0/0, changed state to standby mode R1# R1# R1# R1#show interface bri0/0 BRI0/0 is standby mode, line protocol is down Hardware is PQUICC BRI with U interface Internet address is 10.0.2.1/24 MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation HDLC, loopback not set Last input 00:02:37, output never, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: weighted fair Output queue: 0/1000/64/0 (size/max total/threshold/drops) Conversations 0/1/16 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 83 packets input, 391 bytes, 0 no buffer Received 1 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 90 packets output, 531 bytes, 0 underruns 0 output errors, 0 collisions, 5 interface resets 0 output buffer failures, 0 output buffers swapped out 2 carrier transitions
Example 10-13 provides the complete configuration of R1 for load backup.
Example 10-13. R1's Configuration for Load Backup
R1#show running-config Building configuration... Current configuration : 1070 bytes ! version 12.1 ! hostname R1 ! ip subnet-zero ! isdn switch-type basic-net3 ! interface FastEthernet0/0 ip address 192.168.1.1 255.255.255.0 no ip redirects speed 100 full-duplex ! interface Serial0/0 backup interface BRI0/0 backup load 25 20 ip address 10.0.1.1 255.255.255.0 no ip redirects clockrate 512000 ! interface BRI0/0 ip address 10.0.2.1 255.255.255.0 dialer map ip 10.0.2.2 broadcast 4082222222 dialer-group 1 isdn switch-type basic-net3 ! router ospf 111 log-adjacency-changes network 10.0.1.0 0.0.0.255 area 0 network 10.0.2.0 0.0.0.255 area 0 network 192.168.1.0 0.0.0.255 area 0 ! ip classless ! dialer-list 1 protocol ip permit ! end
Example 10-14 provides the complete configuration of R2 for load backup.
Example 10-14. R2's Configuration for Load Backup
R2#show running-config Building configuration... version 12.1 ! hostname R2 ! ip subnet-zero ! isdn switch-type basic-net3 ! interface Ethernet0/0 ip address 192.168.2.1 255.255.255.0 no ip redirects ! interface Serial0/0 backup load 25 20 backup interface BRI1/0 ip address 10.0.1.2 255.255.255.0 no ip redirects no fair-queue ! interface BRI1/0 ip address 10.0.2.2 255.255.255.0 dialer map ip 10.0.2.1 broadcast 4081111111 dialer-group 1 isdn switch-type basic-net3 ! router ospf 111 log-adjacency-changes network 10.0.1.0 0.0.0.255 area 0 network 10.0.2.0 0.0.0.255 area 0 network 192.168.2.0 0.0.0.255 area 0 ! ip classless ! dialer-list 1 protocol ip permit ! end
Scenario 10-3: Configuring Dialer Profiles for Backup
As mentioned, the use of dialer profiles allows the use of a physical interface for both backup and DDR connections to another site. In this scenario, Routers R1 and R2 are connected via a primary serial line. The routers are also connected via an ISDN line, which has been designated as the backup link. This scenario shows the use of dialer profiles to provide backup for the primary link.
The following steps are required to configure the backup using dialer profiles:
- Step 1. Create and configure a dialer interface:
Router(config)#interface dialer number Router(config-if)#encapsulation ppp Router(config-if)#dialer remote-name name Router(config-if)#dialer string string Router(config-if)#dialer pool number Router(config-if)#dialer-group number
- Step 2. Specify the physical interface that will support the backup. Configure it for PPP encapsulation:
Router(config)#interface type number Router(config-if)#encapsulation ppp Router(config-if)#ppp authentication chap
- Step 3. Make the backup interface a member of the dialer pool:
Router(config-if)#dialer pool member number
- Step 4. Specify the primary interface to be backed up. Specify the dialer interface configured in Step 1 to be used for backup:
Router(config)#interface type number Router(config-if)#backup interface dialer number
- Step 5. Specify what kind of backup is required. For primary link failures, use the backup delay command. For load sharing, use the backup load command:
Router(config-if)#backup delay {enable-delay | never} {disable-delay | never} Router(config-if)#backup load {enable-threshold | never} {disable-load | never}
- Step 6. Specify interesting traffic that will bring up the backup interface using the dialer-list command:
Router(config)#dialer-list dialer-group protocol protocol-name {permit | deny | list access-list-number | access-group}
Example 10-15 shows the use of dialer profiles for backup.
Example 10-15. Configuring the Dialer Interface for Dialer Profiles
R1(config)#interface dialer 0 R1(config-if)#ip unnumbered loopback0 R1(config-if)#encapsulation ppp R1(config-if)#dialer remote-name R2 R1(config-if)#dialer pool 1 R1(config-if)#dialer string 4082222222 R1(config-if)#dialer-group 1 R1(config-if)#exit R1(config)#dialer-list 1 protocol ip permit R1(config-if)#^Z
In Example 10-15, the dialer interface is configured. You can see how most of the legacy DDR commands that used to be configured on a BRI interface are now configured here. You can also see how the dialer-list command is used to define interesting traffic. The number following the dialer-list command should be the dialer-group number specified under the interface.
Example 10-16 shows the configuration of the physical BRI interface used for backup. Note that the dialer pool-member command is used to match the physical BRI backup interface to the logical dialer interface.
Example 10-16. Configuring the Physical BRI Interface for Dialer Profiles
R1(config)#interface bri0/0 R1(config-if)#encapsulation ppp R1(config-if)#dialer pool-member 1 R1(config-if)#ppp authentication chap R1(config-if)#^Z
Example 10-17 shows the configuration of the primary link to be backed up. Notice that the backup interface specified is the virtual dialer interface instead of the physical BRI interface.
Example 10-17. Configuring the Primary Interface for Dialer Profiles
R1(config)#int serial 0/0 R1(config-if)#backup interface dialer 0 R1(config-if)#backup delay 5 10 R1(config-if)#^Z
As soon as the configuration steps are complete, running show commands on the various interfaces gives the results shown in Example 10-18.
Example 10-18. Output of show interface Commands on the Interfaces
R1#show interface s0/0 Serial0/0 is up, line protocol is up Hardware is PowerQUICC Serial Internet address is 10.0.1.1/24 Backup interface Dialer0, failure delay 5 sec, secondary disable delay 10 sec, kickin load not set, kickout load not set MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation HDLC, loopback not set Keepalive set (10 sec) Last input 00:00:03, output 00:00:03, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: weighted fair Output queue: 0/1000/64/0 (size/max total/threshold/drops) Conversations 0/2/256 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 5458 packets input, 365859 bytes, 0 no buffer Received 2900 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 5472 packets output, 364550 bytes, 0 underruns 0 output errors, 0 collisions, 2 interface resets 0 output buffer failures, 0 output buffers swapped out 5 carrier transitions DCD=up DSR=up DTR=up RTS=up CTS=up R1#show interface dialer0 Dialer0 is standby mode, line protocol is down Hardware is Unknown Interface is unnumbered. Using address of Loopback0 (10.0.3.1) MTU 1500 bytes, BW 56 Kbit, DLY 20000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation PPP, loopback not set DTR is pulsed for 1 seconds on reset Last input never, output never, output hang never Last clearing of "show interface" counters 00:02:55 Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: weighted fair Output queue: 0/1000/64/0 (size/max total/threshold/drops) Conversations 0/0/16 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 0 packets input, 0 bytes 0 packets output, 0 bytes R1#show interface bri0/0 BRI0/0 is up, line protocol is up (spoofing) Hardware is PQUICC BRI with U interface MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec, reliability 254/255, txload 1/255, rxload 1/255 Encapsulation PPP, loopback not set Last input 00:00:00, output never, output hang never Last clearing of "show interface" counters 00:01:58 Input queue: 0/75/1/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: weighted fair Output queue: 0/1000/64/0 (size/max total/threshold/drops) Conversations 0/1/16 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 141 packets input, 570 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 1 input errors, 1 CRC, 0 frame, 0 overrun, 0 ignored, 1 abort 40 packets output, 166 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 output buffer failures, 0 output buffers swapped out 6 carrier transitions
Notice that the serial interface now specifies the dialer interface as its backup. Also note that while the dialer interface is in standby mode, the BRI interface is up.
When the primary link goes down, the dialer interface comes up, as shown in Example 10-19.
Example 10-19. Backup Using Dialer Profiles
R1#
07:50:04: %LINK-3-UPDOWN: Interface Serial0/0, changed state to down
07:50:04: %OSPF-5-ADJCHG: Process 111, Nbr 192.168.2.1 on Serial0/0 from FULL to
DOWN, Neighbor Down: Interface down or detached
07:50:05: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed
state to down
07:50:11: %LINK-3-UPDOWN: Interface Dialer0, changed state to up
07:50:49411108400: %LINK-3-UPDOWN: Interface BRI0/0:1, changed state to up
07:50:51539607551: %DIALER-6-BIND: Interface BR0/0:1 bound to profile Di0
07:50:14: %LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0/0:1, changed state to up
07:50:17: %ISDN-6-CONNECT: Interface BRI0/0:1 is now connected to 4082222222 R2
07:50:31: %OSPF-5-ADJCHG: Process 111, Nbr 192.168.2.1 on Dialer0 from LOADING to
FULL, Loading Done
R1#
In Example 10-19, you can see that when the primary serial link goes down, the dialer interface comes up. Also, you can see that OSPF reconverges to run over the dialer interface. This is demonstrated via the output of the show ip route command, as shown in Example 10-20.
Example 10-20. Output of show ip route After the Backup Link Is Up
R1#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 10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C 10.0.3.0/24 is directly connected, Loopback0 C 10.0.3.2/32 is directly connected, Dialer0 C 192.168.1.0/24 is directly connected, FastEthernet0/0 O 192.168.2.0/24 [110/1795] via 10.0.3.2, 00:01:08, Dialer0 R1#ping 192.168.2.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 192.168.2.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 32/33/36 ms R1#
The output of show ip route reveals that the remote Ethernet segment 192.168.2.0 /24 can now be reached via the dialer interface. Pinging R2's Ethernet interface 192.168.2.1 via the backup link shows that the link is up, as shown in Example 10-20.
The complete configuration of R1 for dialer profiles is shown in Example 10-21.
Example 10-21. R1's Configuration for Dialer Profiles
R1#show running-config
Building configuration...
!
version 12.1
!
hostname R1
!
username R2 password 0 cisco
!
isdn switch-type basic-net3
!
interface Loopback0
ip address 10.0.3.1 255.255.255.0
!
interface FastEthernet0/0
ip address 192.168.1.1 255.255.255.0
no ip redirects
speed 100
full-duplex
!
interface Serial0/0
backup delay 5 10
backup interface Dialer0
ip address 10.0.1.1 255.255.255.0
no ip redirects
clockrate 512000
!
interface BRI0/0
no ip address
encapsulation ppp
dialer pool-member 1
isdn switch-type basic-net3
ppp authentication chap
!
interface Dialer0
ip unnumbered Loopback0
encapsulation ppp
dialer pool 1
dialer remote-name R2
dialer string 4082222222
dialer-group 1
!
router ospf 111
log-adjacency-changes
network 10.0.1.0 0.0.0.255 area 0
network 10.0.2.0 0.0.0.255 area 0
network 10.0.3.1 0.0.0.0 area 0
network 192.168.1.0 0.0.0.255 area 0
!
ip classless
!
dialer-list 1 protocol ip permit
!
end
The complete configuration of R2 for dialer profiles is shown in Example 10-22.
Example 10-22. R2's Configuration for Dialer Profiles
R2#show running-config
version 12.1
!
hostname R2
!
username R1 password 0 cisco
!
isdn switch-type basic-net3
!
interface Loopback0
ip address 10.0.3.2 255.255.255.0
!
interface Ethernet0/0
ip address 192.168.2.1 255.255.255.0
no ip redirects
!
interface Serial0/0
backup delay 5 10
backup interface Dialer0
ip address 10.0.1.2 255.255.255.0
no ip redirects
no fair-queue
!
interface BRI1/0
no ip address
encapsulation ppp
dialer pool-member 1
isdn switch-type basic-net3
ppp authentication chap
!
interface Dialer0
ip unnumbered Loopback0
encapsulation ppp
dialer pool 1
dialer remote-name R1
dialer string 4081111111
dialer-group 1
!
router ospf 111
log-adjacency-changes
network 10.0.1.0 0.0.0.255 area 0
network 10.0.2.0 0.0.0.255 area 0
network 10.0.3.2 0.0.0.0 area 0
network 192.168.2.0 0.0.0.255 area 0
!
ip classless
!
dialer-list 1 protocol ip permit
!
end
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