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ISDN BRI dial-peer (busy tone)

tonypearce1
Level 3
Level 3

I've been told that sometimes when a user tries to make an outgoing call they receive a busy signal. There are two ISDN BRI, so four channels. Both are up. I noticed that there are two pots dial-peers, each referencing an ISDN BRI port. Am I correct in thinking that it is possible that a call could randomly pick dial-peer 3000 even if both channels on port 0/1/0 are in use (i.e. busy) with the below configuration?

There is no trunk group configured.

There is the following config on the system:

dial-peer voice 3000 pots

description ##Outgoing Dial-peer##

translation-profile outgoing OUTGOING_TRANSLATION_PROFILE

preference 1

destination-pattern 9T

port 0/1/0

no sip-register

!

dial-peer voice 3001 pots

description ##Outgoing Dial-peer###

translation-profile outgoing OUTGOING_TRANSLATION_PROFILE

preference 1

destination-pattern 9T

port 0/1/1

no sip-register


Show isdn status:

UC520-01#sh isdn status

Global ISDN Switchtype = basic-net3

ISDN BRI0/1/0 interface

        dsl 2, interface ISDN Switchtype = basic-net3

    Layer 1 Status:

        ACTIVE

    Layer 2 Status:

        TEI = 0, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED

    Layer 3 Status:

        0 Active Layer 3 Call(s)

    Active dsl 2 CCBs = 0

    The Free Channel Mask:  0x80000003

ISDN BRI0/1/1 interface

        dsl 3, interface ISDN Switchtype = basic-net3

    Layer 1 Status:

        ACTIVE

    Layer 2 Status:

        TEI = 0, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED

    Layer 3 Status:

        1 Active Layer 3 Call(s)

        CCB:callid=8041, sapi=0, ces=1, B-chan=1, calltype=VOICE

    Active dsl 3 CCBs = 1

    The Free Channel Mask:  0x80000002

    Total Allocated ISDN CCBs = 1

I am thinking it would be better to add both BRI to the trunk group and reference the trunk group in the dial-peer config.

If I were to change the preference of dial-peer 3000 to zero (0), would a third call roll over to dial-peer 3001?

How does the system know when port 0/1/0 is busy when it has two channels?

Thanks,

1 Accepted Solution

Accepted Solutions

It would, but then should re-hunt to the other DP, so that the call only fails when all channels on all ports are in use.

View solution in original post

5 Replies 5

paolo bevilacqua
Hall of Fame
Hall of Fame

Both methods should work. The trunk group is preferred.

Hi Paolo, thanks for replying.

Am I correct with what I think regarding the BRI port and the currently configured dial-peers? i.e the system will occasionally pick the dial-peer with both BRI channels in use, then giving the busy tone?

It would, but then should re-hunt to the other DP, so that the call only fails when all channels on all ports are in use.

I tried to enter the command "no huntstop" but this is default on POTS dial-peers.

I'll have to run some tests to see what is going on. It seems as though the user should not have had any trouble dialing out. Thanks for clarifying!

Appreciated.

Thank you for the nice rating and good luck!