Cannot reach PBX system using data network

[simonator]

Good day Cisco people,

I am Simon and I have a big situation. My company recently expanded to one of our branches. Now this branch houses 100-150 employees. They are using computers and IP phones.

Currently, Our voice and data are integrated into one network.( With no configuration for voice and data vlan on the 5 Cisco switches that distributes the broadcast). We have a Cisco 1941 router used for DHCP for our local data lan and for VPN connection to our Head Office, It's network id is 192.168.65.0/24. Then for the IP Telephony we have Avaya 500 v2 for the PBX, It's network id is 192.168.42.0/24.

Now here is the problem and the questions.

1. I cannot reach the Avaya PBX from the Cisco Router even though I added a static route from the router. ( Do I need to add the route also from the PBX to the router? I want to add that I don't have any experience in voice networking only in data networking.) And is there a way/or is it possible that I could add a route from PBX to router?

2. If I am going to configure two vlans on the switches for the data and voice vlan? Do i need to configure router on the stick on the router? How about the interface that the PBX is connected to? what should I configure it? Should I configure it as a voice vlan only? a trunk port? access port?

3. Lastly, what could be possibly go wrong if ever I configured this on a production environment? And is it that hard to integrate voice with data?

Thank you for your support. I hope you understand. I don't have experience yet in handling both voice and data. Only data networks.

Note: Attached also is a simple network diagram for reference. Thank you.

Have a nice day,

Simon

[mmoulson1]

Hi Simon,

I assume your phones are using static IP addresses to allow them to talk to the PBX?

If your switches have no VLAN configuration then you will have both layer 3 subnets running over the same layer 2 VLAN.

You could do a quick test and put a 192.168.42.X IP address on the interface of the 1941 that connects to your LAN, but use the ‘secondary’ option. This means the router will have both a 192.168.65.X address and a 192.168.42.X address.

You should then be able to PING the PBX from the router.

You will need to configure either a route or default gateway on the PBX of the 192.168.42.X address you have setup on the router to allow it to route packets between the data and voice networks.

A better practice idea as you suggested would be to setup a new VLAN for your voice network. You would need to create a trunk link from the switch to your routers inside interface then configure a sub-interface on the router for both VLANs.

Hope that helps

Matty