1721 ATM dialer backup for serial line

Unanswered Question
Jul 18th, 2007

Hi all,

I've been using the following config for ADSL backup to a serial line, however it seems to show strange behaviour.


interface ATM0

no ip address

no ip mroute-cache

no atm ilmi-keepalive

dsl operating-mode auto

hold-queue 224 in

pvc 0/38

encapsulation aal5mux ppp dialer

dialer pool-member 1

!

!

interface FastEthernet0

description Customer LAN

ip address 1.1.1.1 255.255.255.248

speed auto

!

interface Serial0

description Link to ISP

bandwidth 1024

backup interface Dialer1

ip address 2.2.2.2 255.255.255.252

!

interface Dialer1

ip address negotiated

encapsulation ppp

dialer pool 1

ppp chap hostname [email protected]

ppp chap password 0 1234

ppp pap sent-username [email protected] password 0 1234

!

ip classless

ip route 0.0.0.0 0.0.0.0 Serial0

ip route 0.0.0.0 0.0.0.0 Dialer1 254



When the router boots up with both lines connected, the Dialer1 is set to standby state, whilst the serial is working. If the serial line drops, logging shows the Dialer1 go up, but no further authentication/PPP events are logged and the device doesn't log in.


IF the router is booted up with the serial line disconnected, the ATM interface and dialer interface are brought up and the DSL works, and when the serial line is then brought up/dropped the ATM/Dialer will work each time.


Can anyone advise why this would be the case, or what better way to do the configuration.

We have swapped to using:

interface serial0

backup interface ATM0


So that the whole adsl is disabled until required, however this stops us from checking on ADSL sync/monitoring.


Thanks in advance!


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purohit_810 Wed, 07/18/2007 - 05:23

You has to put...


int dialer1

ppp authentication chap (Should both end same)

idle time-out



router(Conf)#dialer-list 1 protocol ip permit

** Without this DDR will not work **



ip route 0.0.0.0 0.0.0.0 Dialer1 150


andybonyx Wed, 07/18/2007 - 06:21

Thanks for that, sorry I should have mentioned that I had the dialer-list statement.


I have tried adding the ppp authentication and I have the same problem. Here is a log of the config and debug output.


When I manually issue an ATM0 clear, it brings the DSL up


interface ATM0

no ip address

no ip mroute-cache

no atm ilmi-keepalive

dsl operating-mode auto

hold-queue 224 in

pvc 0/38

encapsulation aal5mux ppp dialer

dialer pool-member 1

!

!

interface FastEthernet0

description Customer LAN

ip address 1.1.1.1 255.255.255.248

speed auto

!

interface Serial0

description Link to ISP

bandwidth 1024

backup interface Dialer1

ip address 2.2.2.2 255.255.255.252

!

interface Dialer1

ip address negotiated

encapsulation ppp

dialer pool 1

ppp authentication chap

ppp chap hostname [email protected]

ppp chap password 0 1234

ppp pap sent-username [email protected] password 0 1234

!

ip classless

ip route 0.0.0.0 0.0.0.0 Serial0

ip route 0.0.0.0 0.0.0.0 Dialer1 254

no ip http server

!

dialer-list 1 protocol ip permit

!



00:01:48: %LINK-3-UPDOWN: Interface Serial0, changed state to down

00:01:48: BACKUP(Serial0): event = primary interface went down

00:01:48: BACKUP(Serial0): changed state to "waiting to backup"

00:01:48: BACKUP(Serial0): event = timer expired on primary

00:01:48: BACKUP(Serial0): secondary interface (Dialer1) made active

00:01:48: BACKUP(Serial0): changed state to "backup mode"

00:01:49: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0, changed state to down

00:01:49: BACKUP(Serial0): event = primary interface went down

00:01:50: %LINK-3-UPDOWN: Interface Dialer1, changed state to up

00:01:50: BACKUP(Dialer1): event = secondary interface came up

00:01:51: BACKUP(Dialer1): event = secondary interface came up


00:02:21: BACKUP(Serial0): event = primary interface went down


router#ping 64.233.183.103


Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 64.233.183.103, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5)

router#

router#

router#clear int atm0

router#

00:02:47: ATM0 dslsar_1a_reset: PLIM type is 18, Rate is 288Mbps

00:02:47: ATM0 dslsar_1a_shutdown: state=4

00:02:47: dslsar disable ATM0


00:02:47: Resetting ATM0

00:02:47: dslsar_1a_teardown_vc(ATM0): vc:1 vpi:0 vci:38

00:02:47: dslsar_1a_config(ATM0)

00:02:47: dslsar_1a_enable(ATM0)

00:02:47: ATM0: dslsar_init

00:02:47: ATM0 dslsar_MatchSARTxToLineSpeed(): usbw 288, clkPerCell 52013 prev_clkPerCell 9702

00:02:47: ATM0 dslsar_MatchSARTxToLineSpeed(): Changing line speed from fast to slow

00:02:47: ATM0 dslsar_update_us_bandwidth(): upstream bw =288 Kbps

00:02:48: (ATM0)1a_enable: delay activation of vcd=1, vc=0x82C4CFBC

00:02:48: %LINK-3-UPDOWN: Interface Virtual-Access2, changed state to down

00:02:49: dslsar enable ATM0


00:02:49: ATM0: dslsar_bringup_interface: Interface and atm_db flags are UP

00:02:50: dslsar_txRingParamInit_and_tcqSetup(): default tx-ring setting is selected for vpi/vci = 0/38

00:02:50: ATM0:dslsar_init_tx_chan_desc_per_vc, vcd = 1, addr = 0x00011040, size = 64

00:02:50: ATM0 dslsar_vc_setup: vcd 1

00:02:50: CONFIGURING(ATM0) VC 1 (0/38) IN TX SCHEDULE TABLE SET 0

00:02:50: (ATM0)Forcing Peakrate and Avgrate to: 288

00:02:50: (ATM0)Requested QoS: Peakrate = 288, Avgrate = 288, Burstsize =0

00:02:50: (ATM0)Configuring VC 1: slot 0 in TST 5

00:02:50: (ATM0) SUCCESSFUL CONFIGURATION OF VC 1 (0/38), QOS Type 4

00:02:50: dslsar_setup_cos(ATM0): vc:1 wred_name:- max_q:0

00:02:50: ATM0: vcd = 1, max_tx_time = 7450

00:06:47: Vi2 PPP: No authorization without authentication

00:06:47: Vi2 CHAP: I CHALLENGE id 212 len 35 from "ERX3.Sheffield"

00:06:47: Vi2 CHAP: Using hostname from interface CHAP

00:06:47: Vi2 CHAP: Using password from interface CHAP

00:06:47: Vi2 CHAP: O RESPONSE id 212 len 48 from "[email protected]"

00:06:51: Vi2 CHAP: I SUCCESS id 212 len 4

00:06:52: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access2, changed state to up

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