VoIP System Design – Call Flow

Installing a VoIP solution has a wide range of technical issues that need to be addressed, organized and accounted for. From co-coordinating the “porting” of phone numbers from the old telephone carrier to the new carrier; to determining who has responsibility for providing DHCP and Time services to the new phone devices the technical detail is an endless check list. Generally, we always manage to get all of the technical details correctly identified and successfully implemented. The speeds and feeds all seem to work out and the phones come alive with dial tone and PSTN connectivity. The area that we as a professional service organization are always trying to improve, however, is the very important subject of call flow. Exactly what will an incoming caller to your place of business experience? Will there be a live answering point or will an automated attendant be used? How will calls be handled if the intended call processing solution, either the person or the automated solution is unavailable? Are calls received after normal business hours handled differently? If so how? What about holidays? Unfortunately, though the technical details of a new install are generally always successfully negotiated in time for the “go live”, the entire subject of “call flow” is often neglected until post cut over! Personally, I have found this area of a new installation to be the most demanding and least understood aspect of system design. If there is any area of a new system implementation that needs attention this would be it. The scripting of automated attendant and workgroup, contact center queues needs to be carefully crafted. Time needs to be allocated to the recording of these scripts and both on –hours and off-hour call flow testing needs to be accomplished. After all, the creation of a positive, effective and efficient call flow experience for your client base is what the telephone system is suppose to accomplish in the first place!

A VoIP Deployment will only be as good as your Network!

Remember those old SUN Microsystems commercials? “This is my dog, network. He can get you anything you need”. Well, regardless of the vendor, if you have a network that can barely keep up with user demand for internet access, you are definitely not going to have a successful VoIP deployment. This is why a network assessment is absolutely essential to the future success of your VoIP deployment. Let’s start at the lowest level of the OSI model and work up; cable or level 1. It is the 21st century but your company still has CAT3 cable in the office? This is not going to fly if you want to run VoIP do the desktop! How about those Ethernet switches you bought off eBay three years ago? Are they able to provide Power over Ethernet (POE)? Can you enable VLAN’s? How about interVLAN routing (switch many time, route once)? Ethernet switches and the functionality you need at L2 are mission critical in VoIP deployments. How about L3? If you are using your firewall for a router, you will need to know that “deep packet inspection” necessary to the functionality of a firewall, is a major source of latency in VoIP deployments, so find another default gateway! When you set up a WAN between your far flung, geographically dispersed business locations, will you have access to them? Or will you need to call your carrier every time you want to check your egress queue for QOS? At the end of the day it really will not matter if you went with Mitel, ShoreTel, CISCO, Avaya or Trixbox. If you do not have a properly engineered and managed LAN/WAN in place your VoIP deployment will suck and you will irritate your boss and alienate your users. Get both a network assessment and an ongoing monitoring and network plan in place, including an “acceptable use” policy before you deploy a VoIP solution.