Site to Site Configuration

The 7 characteristics for a successful VoIP implementation

In this post, ‘Site to Site Configuration’, read the seven characteristics to help you prepare VoIP networks and orchestrate any site to site configuration implementation, see the technologies, testing procedures, and how team collaboration improves the entire installation experience.

Recently, I had the opportunity to help a customer integrate a temporary solution, utilizing a channel bank until the ISDN-PRI was delivered. The customer kept getting dropped calls every so often. After deep research and testing we found out the problem was part of antiquated equipment at the Core site where the IP Phones were getting registration and the transcoding from.

To help you avoid future problems follow these 7 characteristics=

1.- The single site deployment approach
2.- What to look for when ready to start
3.- Understand the site to site technology
4.- Pre-testing procedures
5.- Team collaboration
6.- Prepare to fail
7.- Document and improve

1.- The single site deployment approach

Don’t make the same mistake as many, by rushing into deploying a site to site configuration project without testing each site and reassuring that everything works as it should. When you treat each installation this way everything else falls into place, providing both you and the customer a clear idea how each component will be tackled. Here are some ideas=

Hardware and Software – Find out the existing system capacity, ask the customer what is the maximum call volume, how many agents, calls into the an Auto-attendant, etc. Compare those numbers towards the purchased resources.

Site infrastructure – Identify the physical components responsible for handling the day-to-day tasks, as well as server locations, cabling, network switches, and LEC/ISP equipment, etc.

Server locations and environmental requirements – The VoIP equipment should be installed in a secured room with the appropriate temperature, and humidity, and the building ground should be implemented, with surge protectors for the voice equipment, DS1 Trunks, POTS lines, and electrical sources.

2.- What to look for when ready to start

Router and Switching configurations – In your discovery stage ask for a running configuration file for any switches and routers involved in handling the VoIP traffic. Within this file, you are looking for VLAN configurations, DSCP markings, Queue sizes, IP Tables, port speed, and duplex, among other settings.

3.- Understand the site to site technology

MPLS and Metro-E are the two leading MAN and WAN technologies available offered by most Internet Service Providers. Verify it is VoIP complaint and QoS is implemented to help deliver a better voice quality.

4.- Pre-testing procedures

Create a checklist to help you verify all the equipment handling the voice service throughout the VoIP infrastructure. Start by testing the physical wiring and making sure that it is suitable to carry VoIP. Switch-ports and tagging are the next test you want to perform. Confirm VLANs are assigned based on the voice tag, as well as the untagged data packets.

ISP/LEC Trunk Testing – Whether you have POTS, SIP, ISDN-PRI, Dynamic Ts, or Channel Banks, thorough testing must be perform. Here are some techniques I use=

POTS – Loops Start trunks are the most common. When testing POTS you connect the butt-set and make several inbound/outbound calls. Preferably, measure the idle and ring voltages to make sure the readings stays between -48 to 56 volts when on-hook, -8 to -12 volts if idle, and around 90 volts when the line is ringing. On certain occasions, I have seen it go up to 105V. Anything higher than 112, you have to use a line conditioner to avoid future hardware issues.

SIP Trunks – Use a test number to verify that you can authenticate the URI with the ISP STUN and able to make/receive calls.

ISDN-PRI – Check that B-Channels are idle and D-Channel is providing the correct signaling information such as CLID, and other features. Place and receive calls.

Dynamic T1s – These are used to share a single Ethernet Circuit for voice and data. An IAD Router is used to handle these types of circuits. In order to test, you have to have the service provider stress the circuit to find out if there is any dropped packets, CRC errors, etc.

Lastly, connect the ISDN-PRI or SIP Trunk and make test calls.

Channel Bank – A voice T1 is normally use to breakdown the B-Channels into FXO/FXS (POTS Lines) ports to allow the PBX integrate conventional POTS lines. The same rules of POTS lines apply here.

WAN/MAN Testing – Try to have the equipment staged at all sites and generate stress tests as well as making multiple calls.

Network Assessments – These should be done at the customer’s LAN and WAN.

5.- Team collaboration

For best testing results and implementation procedures, it is important to keep constant communication between all parties involved in the project. Start by=

Scheduling Weekly Conf Calls – Use this to bring up any issues and/or concerns such as=

-Server Room Setup – Rack layouts, rack/stack, power outlets layout, HVAC, etc.

ISP/LEC configuration and best practices (Protocols, encryption types, SBCs, etc.)

-LAN Setup – Switch names, Domain controllers, SMTP, LDAP, Network Assessment.

Equipment and phone installation (discuss stages of the implementation)

-Site to Site configuration – Engage the engineers responsible for establishing the connection between all sites and ensure they have all the parameters necessary configured. And if possible, have them test before the VoIP equipment arrives.

6.- Prepare to fail

Keep the customer and everyone else aware of the worse case-scenarios and develop an alternate solution in case the original configuration doesn’t work. Things you can use=

ISP/LEC Redirect – For those sites using a core site as a single point, you can use the service provider to redirect traffic from one site to another bypassing the WAN/MAN network.

7.- Document and improve

Take the project plan, checklist and any other documents and revise them with any updated information. Be sure to add or subtract any parts. This will help improve your data collection for future projects.

Conduct a conference call two weeks after to review the entire project and document anything you would do different in the future, and things you can do to fix the existing design.