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DDR on synchronous serial line - problem with reconnection

Dear Sir!

I've point-to-point link between two routers with such configuration:

R1---R2

R1:

hostname R1

username R2 password cisco

int s0

ip address 1.1.1.1 255.255.255.0

encapsulation ppp

ppp authentication chap

dialer in-band

dialer map ip 1.1.1.2 name R2 broadcast

dialer-group 1

ppp direction callout

dialer-list 1 protocol ip permit

R2:

hostname R2

username R1 password cisco

int s0

ip address 1.1.1.2 255.255.255.0

encapsulation ppp

ppp authentication chap

dialer in-band

dialer map ip 1.1.1.1 name R1 broadcast

dialer-group 1

dialer-list 1 protocol ip permit

Q1: When I no generate any traffic during some time, then DDR disconnects the call (after dialer idle-timeout = 120s default, as I suppose). After that I

can't, for example, ping 1.1.1.2 from R1 or ping 1.1.1.1 from R2.

Why DDR not make the call automatically, even though there are interesting traffic (icmp messages)?

Q2: How can I make the make DDR call manually in this example?

Best regards,

Nick

3 REPLIES
Cisco Employee

Re: DDR on synchronous serial line - problem with reconnection

Ping should re-connect the line again..If not we need to see the following debug

debug dialer

debug ppp authentication

debug ppp negotiation

now you can take the dialer map out from both the sites and just use the the static route like following

On R1

ip route 1.1.1.2 255.255.255.255 serial0

On R2

ip route 1.1.1.1 255.255.255.255 serial0

And ping it after..Router should re-connect the line..

To leave the line connected for more time, just configure "dialer idle-timeout xxx" where xxx is in seconds..

New Member

Re: DDR on synchronous serial line - problem with reconnection

Dear Sir!

I don't know, why to add On R1

ip route 1.1.1.2 255.255.255.255 serial0

On R2

ip route 1.1.1.1 255.255.255.255 serial0

because IOS add it automatically, when I use PPP, nevertheless I did it, and ping 1.1.1.2 from R1 (for example) --> no reaction.

So, I send to you debug dialer, debug ppp authentication & debug ppp negootiation outputs, as you wish:

When I do "no shutdown" on interface Serial0 (router R2), then:

R1# debug ppp negotiation

R1#

%LINK-3-UPDOWN: Interface Serial0, changed state to up

Se0/1 PPP: Using configured call direction

Se0 PPP: Treating connection as a callout

Se0 PPP: Phase is ESTABLISHING, Active Open [0 sess, 1 load]

Se0 LCP: O CONFREQ [Closed] id 66 len 15

Se0 LCP: AuthProto CHAP (0x0305C22305)

Se0 LCP: MagicNumber 0x40330049 (0x050640330049)

Se0 LCP: I CONFREQ [REQsent] id 13 len 15

Se0 LCP: AuthProto CHAP (0x0305C22305)

Se0 LCP: MagicNumber 0x15281E7F (0x050615281E7F)

Se0 LCP: O CONFACK [REQsent] id 13 len 15

Se0 LCP: AuthProto CHAP (0x0305C22305)

Se0 LCP: MagicNumber 0x15281E7F (0x050615281E7F)

Se0 LCP: I CONFACK [ACKsent] id 66 len 15

Se0 LCP: AuthProto CHAP (0x0305C22305)

Se0 LCP: MagicNumber 0x40330049 (0x050640330049)

Se0 LCP: State is Open

Se0 PPP: Phase is AUTHENTICATING, by both [0 sess, 1 load]

Se0 CHAP: O CHALLENGE id 246 len 25 from "R1"

Se0 CHAP: I CHALLENGE id 12 len 25 from "R2"

Se0 CHAP: O RESPONSE id 12 len 25 from "R1"

Se0 CHAP: I SUCCESS id 12 len 4

Se0 CHAP: I RESPONSE id 246 len 25 from "R2"

Se0 CHAP: O SUCCESS id 246 len 4

Se0 PPP: Phase is UP [0 sess, 1 load]

Se0 IPCP: O CONFREQ [Closed] id 29 len 10

Se0 IPCP: Address 1.1.1.1 (0x030614A80141)

Se0 IPCP: I CONFREQ [REQsent] id 12 len 10

Se0 IPCP: Address 1.1.1.2 (0x030614A80142)

Se0 IPCP: O CONFACK [REQsent] id 12 len 10

Se0 IPCP: Address 1.1.1.2 (0x030614A80142)

Se0 IPCP: I CONFACK [ACKsent] id 29 len 10

Se0 IPCP: Address 1.1.1.1 (0x030614A80141)

Se0 IPCP: State is Open

Se0 IPCP: Install route to 1.1.1.2

%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0, changed state to up

R1#<-- & no output after dialer idle-timeout & I ping 1.1.1.2 from R1

R1# debug ppp authentication

%LINK-3-UPDOWN: Interface Serial0, changed state to up

Se0 PPP: Using configured call direction

Se0 PPP: Treating connection as a callout

Se0 CHAP: O CHALLENGE id 247 len 25 from "R1"

Se0 CHAP: I CHALLENGE id 13 len 25 from "R2"

Se0 CHAP: O RESPONSE id 13 len 25 from "R1"

Se0 CHAP: I SUCCESS id 13 len 4

Se0 CHAP: I RESPONSE id 247 len 25 from "R2"

Se0 CHAP: O SUCCESS id 247 len 4

%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0, changed state to up

R1#<--& no output after dialer idle-timeout was ended & I ping 1.1.1.2 from R1

R1#debug dialer

%LINK-3-UPDOWN: Interface Serial0, changed state to up

Se0 DDR: Dialer statechange to up

Se0 DDR: Dialer received incoming call from

Se0 DDR: dialer protocol up

%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0, changed state to up

p1r1#

p1r1# <-- after dialer idle-timeout

Se0 DDR: idle timeout

Se0 DDR: disconnecting call

p1r1#

Se0/1 DDR: re-enable timeout

R1#<--& no output after dialer idle-timeout was ended & I ping 1.1.1.2 from R1

R1 - 2621 with c2600-jk8o3s-mz.122-6.bin installed

R2 - 2611 with c2600-jk8o3s-mz.122-6.bin installed

Q: Why DDR not work at sychronous serial interface upon the whole?

Best regards,

Nick

Cisco Employee

Re: DDR on synchronous serial line - problem with reconnection

The problem you are trying to report is "connection will not re-establised for a ping across" ..So i wnat you to test with the static host routes to see if that fix it or not..

If you don't want that then need to see what happens when you ping again after connection went down after idle-timeout..Turn on

debug ip pack detail

Let's see what you get..

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