Dialer Watch

[Ahmede]

We have 3640 running IOS 12.2.17a, we are using EIGRP. We are using ISDN BRI to backup the main frame circuit. We are using Dialer-watch to initiate the backup link.

For some reason, the backup link comes up and stays up while the main link is up and the route we are watching is still in the routing table. The ISDN stays up till we disable the link. Any idea what could be the reason for that.. When the backup link is up I still can see the watched route in the routing table, known via the frame link.

Here?s the config we are using

interface Dialer1

bandwidth 50

ip address x.x.x.x y.y.y.y

encapsulation ppp

no ip route-cache cef

dialer in-band

dialer idle-timeout 300

dialer wait-for-carrier-time 60

dialer watch-disable 60

dialer string xxxxxxxxxx

dialer hold-queue 75

dialer load-threshold 33 either

dialer watch-group 1

dialer-group 1

ppp authentication chap

ppp multilink

!

access-list 137 deny eigrp any any

access-list 137 permit ip any any

!

dialer watch-list 1 ip x.x.x.x 255.255.255.0

dialer-list 1 protocol ip list 137

!

Thaks fr your help..

[sundar.palaniappan]

Hi,

Can you post the output of 'show dialer' when both the frame and ISDN links are up. Moreover, can you post the ISDN relevant config from the router on the other end.

Sundar

[Ahmede]

That's show dialer that was captured earlier today during the problem. Please note that "the reason for call" source and destination IP address keep changing

router2#sh dialer interface bri 1/2:1

BRI1/2:1 - dialer type = ISDN

Idle timer (300 secs), Fast idle timer (20 secs)

Wait for carrier (60 secs), Re-enable (15 secs)

Dialer state is multilink member

Dial reason: ip (s=x.x.x.x, d=y.y.y.y)

Current call connected 00:03:21

Connected to xxxxxxx (router3)

interface BRI1/2

bandwidth 50

no ip address

encapsulation ppp

dialer rotary-group 1

isdn switch-type basic-net3

no cdp enable

ppp authentication chap

ppp multilink

!

Please note that during the problem the traffic destined to the watched subnet is still using the frame link..

Thanks..

[sundar.palaniappan]

Dial reason: ip (s=x.x.x.x, d=y.y.y.y)

Did you do a show ip route y.y.y.y when you saw this. Was it pointing to the ISDN next-hop?

[Ahmede]

No.. y.y.y.y should follow the defuly route.. And the defualt route is known via EIGRP (via the Frame) and it has not chnaged during the problem..

[sundar.palaniappan]

If you had a specific route (y.y.y.y) via ISDN then the router wouldn't use the default route via frame to forward traffic. Your options are to filter any specific routes via ISDN (or) reconfigure your dialer list to permit only the watched network from bringing up the ISDN link.

HTH

Sundar

[Ahmede]

I ran debug for the DDR, and it seems that two machines are trying to access some IP's from the range used on the Dialer interface and becuase it's connected so it brings up the backup...

Thanks for your help..

[cisco_trouble]

are using a floating static route?