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Community Member

ISDN PRI used for backup

i have configured an isdn PRI for backup to a leased line.the remote router dials in my router when LL goes down .a max of 27 channels has been set for the backup.

now backup fires properly when LL goes down and isdn comes up.but prob is first some channels get connected -say 7-8 (from 0 to 7),then they get disconnected suudenly and then next few channels (after 7) come up.same again they will get disconnected and this cycle goes on.in sense backup is not remaining stable .

ne suggestions?

13 REPLIES

Re: ISDN PRI used for backup

The behaviour you describe is typical for a DDR link that is almost idle. In other words: There is too little traffic to keep the lines up continuously.

This may have several causes:

- traffic is not properly routed over the backup link

- incorrect dialer-list permitting no traffic

- dialer load treshold is set too high

You will need to check this at both ends. Stating all this, I presume that dialling and authentication are configured correctly.

Regards,

Leo

Community Member

Re: ISDN PRI used for backup

dialer list is permitting all ip and ipx traffic .load threshold is just 1 %.

and if the load is less,then some channels should get disconnected.but all 8-9 channels get disconnected at the same time .and connection again happens from further channels (not the same).after every 30 secs,1 new channel comes up.but while disconnection all get disconnected immediately.

Re: ISDN PRI used for backup

I suppose there is no data going over the link at all then?

Could you post the output of during connection setup and the subsequent dropping and renewal of the connection?

Leo

Community Member

Re: ISDN PRI used for backup

i m pasting here debug output -i have made it lil shorter by removing redundant stuff and added a few lines in brackets

14w2d: %LINK-3-UPDOWN: Interface Serial1/0:0, changed state to up

14w2d: %DIALER-6-BIND: Interface Se1/0:0 bound to profile Di2

14w2d: %DIALER-6-BIND: Interface Vi2 bound to profile Di2

14w2d: %LINK-3-UPDOWN: Interface Virtual-Access2, changed state to up

14w2d: %LINK-3-UPDOWN: Interface Serial1/0:1, changed state to up

14w2d: %ISDN-6-CONNECT: Interface Serial1/0:0 is now connected to

14w2d: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/0:0, changed stat

e to up

14w2d: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access2, changed

state to up

14w2d: %DIALER-6-BIND: Interface Se1/0:1 bound to profile Di2

14w2d: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/0:1, changed stat

e to up

(like this went till chan 4)

14w2d: %ISDN-6-DISCONNECT: Interface Serial1/0:0 disconnected from (deleted), call lasted 157 seconds

14w2d: %ISDN-6-DISCONNECT: Interface Serial1/0:1 disconnected from , call lasted 156 seconds

14w2d: %ISDN-6-DISCONNECT: Interface Serial1/0:2 , call lasted 126 seconds

14w2d: %ISDN-6-DISCONNECT: Interface Serial1/0:3 disconnected from , call lasted 96 seconds

14w2d: Vi2 Debug: Condition 1, interface Se1/0:3 cleared, count 0

14w2d: %DIALER-6-UNBIND: Interface Vi2 unbound from profile Di2

14w2d: %LINK-3-UPDOWN: Interface Virtual-Access2, changed state to down

14w2d: %LINK-3-UPDOWN: Interface Serial1/0:4, changed state to down

14w2d: %LINK-3-UPDOWN: Interface Serial1/0:1, changed state to down

14w2d: %LINK-3-UPDOWN: Interface Serial1/0:0, changed state to down

14w2d: %LINK-3-UPDOWN: Interface Serial1/0:3, changed state to down

14w2d: Se1/0:3 LCP: State is Closed

14w2d: Se1/0:3 PPP: Phase is DOWN

14w2d: %LINK-3-UPDOWN: Interface Serial1/0:2, changed state to down

14w2d: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/0:4, changed stat

e to down

14w2d: %LINK-3-UPDOWN: Interface Serial1/0:5, changed state to up

14w2d: %DIALER-6-BIND: Interface Se1/0:5 bound to profile Di2

14w2d: %DIALER-6-BIND: Interface Vi3 bound to profile Di2

14w2d: %LINK-3-UPDOWN: Interface Virtual-Access3, changed state to up

14w2d: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/0:5, changed stat

e to up

14w2d: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access3, changed

state to up

14w2d: %LINK-3-UPDOWN: Interface Serial1/0:6, changed state to up

(after some time ) : sh users

Se1/0:5 Sync PPP -

Se1/0:6 Sync PPP -

Se1/0:7 Sync PPP -

Se1/0:8 Sync PPP -

Se1/0:9 Sync PPP -

Se1/0:10 Sync PPP -

Se1/0:11 Sync PPP -

Se1/0:12 Sync PPP -

Se1/0:13 Sync PPP -

Se1/0:14 Sync PPP -

Se1/0:16 Sync PPP -

Se1/0:17 Sync PPP -

Se1/0:18 Sync PPP -

(after that .. )

14w2d: %DIALER-6-UNBIND: Interface Se1/0:16 unbound from profile Di2

14w2d: %DIALER-6-UNBIND: Interface Se1/0:17 unbound from profile Di2

14w2d: %DIALER-6-UNBIND: Interface Se1/0:18 unbound from profile Di2

14w2d: %DIALER-6-UNBIND: Interface Se1/0:19 unbound from profile Di2

14w2d: %DIALER-6-UNBIND: Interface Se1/0:5 unbound from profile Di2

14w2d: %DIALER-6-UNBIND: Interface Se1/0:6 unbound from profile Di2

14w2d: %DIALER-6-UNBIND: Interface Se1/0:7 unbound from profile Di2

14w2d: %DIALER-6-UNBIND: Interface Se1/0:8 unbound from profile Di2

14w2d: %DIALER-6-UNBIND: Interface Se1/0:9 unbound from profile Di2

14w2d: %DIALER-6-UNBIND: Interface Se1/0:10 unbound from profile Di2

14w2d: %DIALER-6-UNBIND: Interface Se1/0:11 unbound from profile Di2

14w2d: %DIALER-6-UNBIND: Interface Se1/0:12 unbound from profile Di2

(then again same cycle)

14w2d: %LINK-3-UPDOWN: Interface Serial1/0:23, changed state to up

Community Member

Re: ISDN PRI used for backup

Can you post a debug from "debug ppp authen", "debug ppp neg", and "debug isdn q931"? Maybe your routers are not authenticating correctly with each other.

Silver

Re: ISDN PRI used for backup

What I beleive is happening is the dialer load threshold is kicking in ,

try to use this command and see if the problem continues

'dialer load-threshold 250' THis will allow addtional channels to be brought up when the load on the interface hits 250/255 and not until then , also check the bandwidth statement on the physical interface , this is what determines the load, make sure it matches the size of the pipe.

Community Member

Re: ISDN PRI used for backup

i made max links as 10 and then tried .i m pasting output here .1 thing wht i noted is whe nchannels are getting disconnected the ppp shows missed 5 keepalives .is tht the problem ? and wht does tht mean ?

14w3d: %LINK-3-UPDOWN: Interface Serial0/1, changed state to down

14w3d: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, changed state

to down

14w3d: ISDN Se1/0:15: Incoming call id = 0xDD4

14w3d: %LINK-3-UPDOWN: Interface Serial1/0:0, changed state to up

14w3d: %DIALER-6-BIND: Interface Se1/0:0 bound to profile Di2

14w3d: %DIALER-6-BIND: Interface Vi2 bound to profile Di2

14w3d: %LINK-3-UPDOWN: Interface Virtual-Access2, changed state to up

14w3d: %LINK-3-UPDOWN: Interface Serial1/0:1, changed state to up

14w3d: %ISDN-6-CONNECT: Interface Serial1/0:0 is now connected to

14w3d: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/0:0, changed stat

e to up

14w3d: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access2, changed

state to up

14w3d: %DIALER-6-BIND: Interface Se1/0:1 bound to profile Di2

14w3d: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/0:1, changed stat

e to upp

14w3d: %ISDN-6-CONNECT: Interface Serial1/0:1 is now connected to

14w3d: %ISDN-6-CONNECT: Interface Serial1/0:2 is now connected to

14w3d: ISDN Se1/0:15: Incoming call id = 0xDD7

14w3d: %LINK-3-UPDOWN: Interface Serial1/0:3, changed state to up

14w3d: %ISDN-6-CONNECT: Interface Serial1/0:2 is now connected to

14w3d: Se1/0:3 PPP: Treating connection as a callin

14w3d: Se1/0:3 PPP: Phase is ESTABLISHING, Passive Open

14w3d: Se1/0:3 LCP: State is Listen

14w3d: Se1/0:3 LCP: I CONFREQ [Listen] id 26 len 33

14w3d: Se1/0:3 LCP: AuthProto PAP (0x0304C023)

14w3d: Se1/0:3 LCP: MagicNumber 0xCE74C0EA (0x0506CE74C0EA)

14w3d: Se1/0:3 LCP: MRRU 1524 (0x110405F4)

14w3d: Se1/0:3 LCP: EndpointDisc 1 Local (0x130F014272697472424C5244617461)

14w3d: Se1/0:3 LCP: O CONFREQ [Listen] id 89 len 30

14w3d: Se1/0:3 LCP: AuthProto PAP (0x0304C023)

14w3d: Se1/0:3 LCP: MagicNumber 0x10242E6F (0x050610242E6F)

14w3d: Se1/0:3 LCP: MRRU 1524 (0x110405F4)

14w3d: Se1/0:3 LCP: EndpointDisc 1 Local (0x130C0162726974616E6E6961)

14w3d: Se1/0:3 LCP: O CONFREJ [Listen] id 26 len 8

14w3d: Se1/0:3 LCP: AuthProto PAP (0x0304C023)

14w3d: Se1/0:3 LCP: I CONFACK [REQsent] id 89 len 30

14w3d: Se1/0:3 LCP: AuthProto PAP (0x0304C023)

14w3d: Se1/0:3 LCP: MagicNumber 0x10242E6F (0x050610242E6F)

14w3d: Se1/0:3 LCP: MRRU 1524 (0x110405F4)

14w3d: Se1/0:3 LCP: EndpointDisc 1 Local (0x130C0162726974616E6E6961)

14w3d: Se1/0:3 LCP: I CONFREQ [ACKrcvd] id 27 len 34

14w3d: Se1/0:3 LCP: AuthProto CHAP (0x0305C22305)

14w3d: Se1/0:3 LCP: MagicNumber 0xCE74C0EA (0x0506CE74C0EA)

14w3d: Se1/0:3 LCP: MRRU 1524 (0x110405F4)

14w3d: Se1/0:3 LCP: EndpointDisc 1 Local (0x130F014272697472424C5244617461)

14w3d: Se1/0:3 LCP: O CONFACK [ACKrcvd] id 27 len 34

14w3d: Se1/0:3 LCP: AuthProto CHAP (0x0305C22305)

14w3d: Se1/0:3 LCP: MagicNumber 0xCE74C0EA (0x0506CE74C0EA)

14w3d: Se1/0:3 LCP: MRRU 1524 (0x110405F4)

14w3d: Se1/0:3 LCP: EndpointDisc 1 Local (0x130F014272697472424C5244617461)

14w3d: Se1/0:3 LCP: State is Open

14w3d: Se1/0:3 PPP: Phase is AUTHENTICATING, by both

14w3d: Se1/0:3 CHAP: I CHALLENGE id 12 len 33 from ""

14w3d: Se1/0:3 CHAP: Waiting for peer to authenticate first

14w3d: Se1/0:3 PAP: I AUTH-REQ id 12 len 26 from ""

14w3d: Se1/0:3 PAP: Authenticating peer

14w3d: Se1/0:3 PAP: O AUTH-ACK id 12 len 5

14w3d: Se1/0:3 CHAP: Processing saved Challenge, id 12

14w3d: %DIALER-6-BIND: Interface Se1/0:3 bound to profile Di2

14w3d: Se1/0:3 CHAP: O RESPONSE id 12 len 30 from ""

14w3d: Se1/0:3 CHAP: I SUCCESS id 12 len 4

14w3d: Se1/0:3 PPP: Phase is VIRTUALIZED

14w3d: Vi2 Debug: Condition 1, interface Se1/0:3 triggered, count 1

14w3d: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/0:3, changed stat

e to up

14w3d: %ISDN-6-CONNECT: Interface Serial1/0:3 is now connected to

(went on till 9 .i.e 10 chan came up)

14w3d: %DIALER-6-UNBIND: Interface Se1/0:4 unbound from profile Di2

14w3d: %DIALER-6-UNBIND: Interface Se1/0:5 unbound from profile Di2

14w3d: %DIALER-6-UNBIND: Interface Se1/0:6 unbound from profile Di2

14w3d: %DIALER-6-UNBIND: Interface Se1/0:7 unbound from profile Di2

14w3d: %DIALER-6-UNBIND: Interface Se1/0:8 unbound from profile Di2

14w3d: %DIALER-6-UNBIND: Interface Se1/0:9 unbound from profile Di2

14w3d: %DIALER-6-UNBIND: Interface Se1/0:0 unbound from profile Di2

14w3d: %DIALER-6-UNBIND: Interface Se1/0:1 unbound from profile Di2

14w3d: %DIALER-6-UNBIND: Interface Se1/0:2 unbound from profile Di2

14w3d: Se1/0:3 PPP: Missed 5 keepalives, taking LCP down

14w3d: Se1/0:3 PPP: Phase is DOWN

14w3d: %DIALER-6-UNBIND: Interface Se1/0:3 unbound from profile Di2

14w3d: Se1/0:3 PPP: Phase is ESTABLISHING, Passive Open

14w3d: Se1/0:3 LCP: State is Listen

14w3d: Vi2 Debug: Condition 1, interface Se1/0:3 cleared, count 0

14w3d: %DIALER-6-UNBIND: Interface Vi2 unbound from profile Di2

14w3d: %ISDN-6-CONNECT: Interface Serial1/0:9 is now connected to

14w3d: %ISDN-6-DISCONNECT: Interface Serial1/0:4 disconnected from , call lasted 412 seconds

14w3d: %ISDN-6-DISCONNECT: Interface Serial1/0:5 disconnected from , call lasted 382 seconds

14w3d: %ISDN-6-DISCONNECT: Interface Serial1/0:6 , call lasted 352 seconds

14w3d: %ISDN-6-DISCONNECT: Interface Serial1/0:0 disconnected from call lasted 503 seconds

14w3d: %ISDN-6-DISCONNECT: Interface Serial1/0:1 disconnected from , call lasted 502 seconds

14w3d: ISDN Se1/0:15: Incoming call id = 0xDDE

14w3d: %LINK-3-UPDOWN: Interface Serial1/0:10, changed state to up

14w3d: %DIALER-6-BIND: Interface Se1/0:10 bound to profile Di2

14w3d: %DIALER-6-BIND: Interface Vi3 bound to profile Di2

14w3d: %LINK-3-UPDOWN: Interface Virtual-Access3, changed state to up

14w3d: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/0:10, changed sta

te to up

14w3d: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access3, changed

state to up

ya also did with threshold of 200.only 1 channel came as there was very less load.but even tht got disconnected after some time and next came up.

1 more thing -in debug output,the messages of PPP-LCP come only in s1/0:3.

this time chan 14 had come up.when it got disconnected ,i didnt get any PPP-LCP output.

y is tht so ?

Community Member

Re: ISDN PRI used for backup

How are you initiating the backup, backup interface? floating static? dialer watch?

I believe the call hangs up due to the "dialer idle-timeout". If your not seeing any interesting traffic, the idle-timeout can expire and drop the call. The backup interface command which initiated the call will reconnect if it is still active.

HTH

Community Member

Re: ISDN PRI used for backup

idle timeout is 50 min .and interestig trafffic is entire ip.soi dont think tht should be the reason. baackup delay is 5 5 .but tht will come in to picture when leased line comes up .

Community Member

Re: ISDN PRI used for backup

what is the IOS version you are using? Cant it be also a suspect?

kindly take take the sh tech and output interpreter and chect it against all possible bugs. As every configuration seem to be fine so far.

Regards

WS

Community Member

Re: ISDN PRI used for backup

IOS version is 12.0(10) ,PRI Software version -1.1.remote router has 12.0(5)

can u tell me how to use output interpretor and bug toolkit?

Community Member

Re: ISDN PRI used for backup

and ya -as i had said earlier -in the output of debug,u can see when channels get disconnected the error comes as :

Se1/0:3 PPP: Missed 5 keepalives, taking LCP down.

wht is this error ?

Community Member

Re: ISDN PRI used for backup

Take a look at this link...

Troubleshooting Serial Line Problems

http://www.cisco.com/en/US/partner/tech/tk713/tk628/technologies_troubleshooting_procedures09186a00800a758d.shtml

It looks like you may have a clocking issue between your CSU/DSU and the service provider equipment causing you to miss some keepalives and therefore dropping the link.

HTH

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