Does FXO interfaces detect the line protocol going down

[albinashaikh]

hi,

There are 8 FXO interfaces on a router with 8  Trunk/PSTN links terminated on it. This FXO interfaces are grouped  together with the trunk group command. so whenver the first line is busy  automatically the next available link/line will be used.

I  have observed that, if the link is removed from the first FXO port then  the calls are dropped it does not go to the next available link/line in  the trunk group. Then i have to manually shut the interface.

so  is there an option available for the FXO interfaces that whenever the  PSTN/Trunk link goes down it is detected and it starts using the next  available lines in the group.

The way the line protocol status goes up and down with the serial or ethernet interfaces whenever the cable is removed.

From  some of the documents i have come across that the FXO interfaces uses  TIP and Ring mechanism. so basically it only detects the line going  off-hook or on-hook. so does that means that it cannot detect the line  protocol going down?

Regards,

Albina Shaikh

[Anas Abueideh]

Hi,

unfortunately FXO can't detect the line if it goes down. it only send and recive calls.

for your configuration, try to remove trunk config and use dialpeers with precedence. that means your config will become larger. for me I have alot of issuea with trunk especially when there is a line down. you can start with changing one dialpeer and test with removing one line to simulate the line down.

HTH
Anas

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[paolo bevilacqua]

Trunk-group can detect circuit failure and rehunt to next member. Configure a voice class causecode with "no circuit", and apply to the trunk group.

[acampbell]

Albina,

Please read this link to the command

dial-peer outbound status-check pots

no dial-peer outbound status-check pots

http://www.cisco.com/en/US/docs/ios/12_3t/voice/command/reference/vrht_d1_ps5207_TSD_Products_Command_Reference_Chapter.html#wp1459139

Regards,
Alex.
Please rate useful posts.

[albinashaikh]

The Following configuration detects the removal of the cable from the FXO interface:

voice-port 0/0/0

cable-detect

After the cable removal, the operation state changes to "down" instead of "dorm" and the outgoing status changes to "off-hook".. This makes the port to be busy and thus the other available line in the trunk group is used for making calls.

Regards,

Albina Shaikh