[cisco-voip] Modem PassThrough

[Ramiz Sardar]

Friends,

I configured routers with for modem passthrough. When my modem dial RAS
number, It starts negotiation with RAS but keep negotiate and not connected.
Means repeat negotiation again and again till timeout. Once it surprisingly
connected but within 30 sec it disconnected. Network Topology below:

RAS--------PBX-----Rt-A--------------------Rt-B----PBX-----------DialupUser

And Configuration below:

hostname Rt-B

isdn switch-type primary-qsig

voice service voip
 modem passthrough nse codec g711alaw



controller E1 0/0/0
 channel-group 0 timeslots 1-31

controller E1 0/1/0
 pri-group timeslots 1-31

interface Serial0/0/0:0
 ip address 10.0.0.2 255.255.255.252

interface Serial0/1/0:15
 no ip address
 encapsulation hdlc
 isdn switch-type primary-qsig
 isdn overlap-receiving
 isdn incoming-voice voice
 isdn bchan-number-order ascending
 no cdp enable

router ospf 100
network 0.0.0.0 255.255.255.255 area 0

dial-peer voice 786 voip
  destination-pattern 786$
  modem passthrough nse codec g711alaw
 session target ipv4:10.0.0.1
 no vad
!
dial-peer voice 785 pots
 incoming called-number 786$
 direct-inward-dial
 port 0/1/0:15


-------- Router A ---------

 hostname Rt-A
isdn switch-type primary-qsig
!

voice service voip
 modem passthrough nse codec g711alaw
!
controller E1 0/0/0
 channel-group 0 timeslots 1-31

controller E1 0/1/0
 pri-group timeslots 1-31

interface Serial0/0/0:0
 ip address 10.0.0.1 255.255.255.252

router ospf 100
 network 0.0.0.0 255.255.255.255 area 0

dial-peer voice 786 pots
 destination-pattern 786$
 direct-inward-dial
 port 0/1/0:15
 forward-digits 3
!
dial-peer voice 785 voip
 modem passthrough nse codec g711alaw
 incoming called-number 786$
 no vad

Waiting for your immediate response.......

Best Regards


On Jan 9, 2008 9:42 PM, Scott Voll <svoll.voip at gmail.com> wrote:

> Modem pass through is just like Fax passthrough.  both need to run over a
> G711 codec.
>
> config is pretty simple.  just add the following commands:
>
> H323 looks like this:
>  voice service voip
>  h323
>  modem passthrough nse codec g711ulaw
>
> Also make sure you have VAD turned off on the dial peer(s)
>
> MGCP looks like this:
>
> mgcp modem passthrough voip mode nse
>
> Scott
>
>
> On Jan 9, 2008 7:15 AM, Ramiz Sardar <ramizchaudhary at gmail.com> wrote:
>
> > Friends,
> >
> > I am currently working on voip setup. With the existing tdm network,
> > dialup users from different sites dial Remote Access Server in central site.
> > When i will put routers into that network, can users be able to connect
> > again via voip setup. Topology includes cisco 3800 routers that connect with
> > Ericson MD110 pbx through E1 (Pri Qsig). Routers are connected point to
> > point through E1. RAS is non-cisco.
> >
> > Existing Topology:
> >
> > IP Network
> > ---------RAS------------PBX--------------------------------------------PBX--------------Dialup
> > User (Modem)
> >
> > Topology after voip setup:
> >
> > IP Network
> > ---------RAS------------PBX---------Router-----------------------------Router--------PBX--------------Dialup
> > User (Modem)
> >
> > With some study i come to know that there is concept of modem
> > passthrough that can be used but someone please explain it briefly. And if
> > someone currently using it, please write down a sample configuration
> > according to my voip topology.
> >
> > Best Regards
> >
> > _______________________________________________
> > cisco-voip mailing list
> > cisco-voip at puck.nether.net
> > https://puck.nether.net/mailman/listinfo/cisco-voip
> >
>
>
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