voice muxed with data over MultilinkPPP

[dshapin]

I have two point to point T1 leased lines. One is used for data, the other for voice to connect two PBX phone systems. I would like to double the data bandwidth by runnung data over both T1's using MultilinkPPP, and also and multiplex voice to connect the PBX phone systems. Is this possible? Could I use an ADC Kentrok DataSmart Add/Drop to split off 16 channels for voice and bond the other 8 channels with the other T1? Any other options? I have two 3640 routers at each end.

Thanks.

Dan.

[igor.sotelo]

Hi Dan,

The 3640 is a powerful router, and more impotant it's a multiservice router. So it can handle Cisco Systems own VIC's.

In VoIP there are codec's that take as little as 5.3 Kbps. So, 16 voice channels would take 84.8 Kbps, little more with the IP header. T1 for 100 Kbps seems way to much. Even with standard 8 Kbps voice codec that would be 128 Kbps plus something. This codec, allow you to use fax and V.92 modem's over them.

My recommendation is to install both T1 for data communication and to use VoIP. With high density voice interface cards you can connect 16 channels per PBX. In this case you will need to configure QoS for voice use, perhaps for data too.

Best Regards,

Igor Sotelo.

[tepatel]

You can run data and voice togather on both the links. You can use the advantage of ppp multilink using fragmentation and interleaving.

Here is the best url which discuss exactly that VoIP over PPP Links with Quality of Service for voice and data togather

http://www.cisco.com/warp/public/788/voice-qos/voip-mlppp.html

[dshapin]

Hi,

If I combine the voice channels with the data channels then for the two legacy PBX systems (Siemens 9200) wont I need a FXO module in the 3640s at each end of the the T1, which connect to the T1 cards in the PBX?

Will I still have the same functionality, 4 digit dialing between PBX phone systems?

Thanks.

Dan.

[igor.sotelo]

Hi Dan,

Cisco makes T1 Voice/WAN Interface Card (V/WIC). http://www.cisco.com/warp/public/cc/pd/rt/1700/prodlit/t1e1m_ds.pdf

The brochure is for 1700 router, but the card is also compatble with 3600 series routers. This card suppors 5.3 Kbps and 8 Kbps codecs, has two T1 ports, and says that it supports up to 30 voice ports on 1700 with voice support models. I don't have experience with them and there may be some kind of complication.

There are three types of VIC's. FXO used for PSTN and legacy extension PBX ports, FXS used for analogic phones, faxes and modems, also for legacy CO PBX lines, and E&M used for both modern PBX and PSTN systems.

If you want to connect the extension ports of the PBX to the router, and if Siemens says they use FXO ports for extensions you can use FXO modules. You may also need:

* Network Module to support voice application,

* Perhaps additional DSP's dependieng on specified codec's and number of voice ports,

* IOS IP Plus future set, and perhaps additional memory ROM and RAM for the IP Plus.

Also take note, that FXO to FXO connection present disconnection isues. And finaly FXO ports are full functional. They can be programmed for 4 digit dialing, as well as for PLAR connections.

Best Regards,

Igor Sotelo.