Here's an interesting case study that I received from a reader and VoiceCon attendee, Todd Vinciguerra, telecommunications analyst at Florida-based Riverside Bank:
Do Not Throw Away That Legacy PBX Yet!
I have been attending VoiceCon and Internet Telephony conferences for the past two years, and have found something very interesting and kind of left out of current discussions. While salesmen and companies need to sell new equipment, I work for a financial institution, and spending the money necessary for a full blown 60 + branch IP PBX conversion is not in the short term plan for us--but as a company we are reaping great rewards from some IP benefits that we can derive today while still using our TDM PBX.
While SIP and IP-PBX implementations have been growing in popularity over the past few years, today's economic climate has slowed down its pace. We should not let the down turn of the economy and diminishing budgets deter companies from benefiting from SIP today.
By combining SIP trunks, a Cisco gateway and T1 connections into your TDM (time-division multiplexing) PBX, companies do not need to forklift their TDM PBX to realize the ROI of SIP for a fraction of the cost of purchasing a new IP PBX! By adding this step in your design process, you are building the infrastructure for the time when the organization can upgrade to an IP PBX.
This particular SIP trunking implementation that we undertook did in fact need the intermediary step of installing the Cisco gateway due to the fact that our legacy PBX is not inherently compatible with the SIP protocol. Depending on the type of PBX in your organization you may not need the gateway for the PBX to connect to the Internet T1s. Also, you may not have clear cut instructions how to make the implementation work. I often joked that I was going to write a book on the topic because I had to draw from so many different informational sources to complete this implementation, I wanted an easier step by step guide that did not exist. Even some provisioning engineers at the NOC wanted my design.
In this implementation, we are using Internet T1s for our inbound 800 service and outbound long distance calling, integrating into a TDM-based PBX;as simple as that. There is a conversion from digital to analog and back. As noted, we are using SIP trunking with a PBX that does not inherently understand SIP, so the implementation needed to include a gateway to interface between the Internet T1s and the Analog signal expecting T1 cards in the PBX to carry the CO type signaling, including framing, clocking and line code to this PBX. We also opted to use two different carriers for the provisioning of the Internet T1 circuits for vendor diversification and to help mitigate against potential outages within one vendor's network.
I have found out many interesting details working with two providers, finding out that some sales teams are just not up to speed on their own company's services, let alone mixing types of services for a more custom approach as this type of conversion. I had to pull the plug on one vendor when I found out that we would have been the first company in Florida to use their service and did not yet have enterprise level references. I tried to convert two year ago with them, now I am using another vendor.
There were many challenges that were faced in this implementation. First off was carrier selection. The carriers have different types of SIP trunking, or business VoIP solutions available. You will need to find out what options work best in your situation. For ours, I wanted to have more control of our 800 numbers and call flow patterns personally. I have the ability to change routing options at will. There are different codec and sampling rates available. Based on your selection, you can receive different amounts of concurrent calls over the Internet T1. Security is a major concern for us at the bank; we need to pay close attention to keeping the gateway secure against unauthorized users. With the different carriers, there are different types of reporting available. You may need to create a custom report to share the information that is desired.
The ROI for this project was within two months. Our savings were in the change in transport method and competitive pricing. With the selected codec and compression from the SIP provider, for every Internet T1 that was turned up, two PRIs or T1s were removed. All inbound 800-traffic; and outbound long distance from the operations center come in and out of this gateway. Load balancing inbound and outbound with multiple failovers for each was designed. For improved total uptime, a second gateway was installed as a high availability failover, handling half of the original gateway's capacity. This high availability gateway is in full production as well. So the design had to be modified on both gateways to include proper load balancing and redundancy over multiple links and interfaces for both inbound and outbound calling.
All is working properly and management is happy. Now the planning has begun for the IP PBX conversion. We experienced some headaches along the way, but the ultimate success helped alleviate that pain. This was a very fun project!
I have been attending VoiceCon and Internet Telephony conferences for the past two years, and have found something very interesting and kind of left out of current discussions. While salesmen and companies need to sell new equipment, I work for a financial institution, and spending the money necessary for a full blown 60 + branch IP PBX conversion is not in the short term plan for us--but as a company we are reaping great rewards from some IP benefits that we can derive today while still using our TDM PBX.
While SIP and IP-PBX implementations have been growing in popularity over the past few years, today's economic climate has slowed down its pace. We should not let the down turn of the economy and diminishing budgets deter companies from benefiting from SIP today.
By combining SIP trunks, a Cisco gateway and T1 connections into your TDM (time-division multiplexing) PBX, companies do not need to forklift their TDM PBX to realize the ROI of SIP for a fraction of the cost of purchasing a new IP PBX! By adding this step in your design process, you are building the infrastructure for the time when the organization can upgrade to an IP PBX.
This particular SIP trunking implementation that we undertook did in fact need the intermediary step of installing the Cisco gateway due to the fact that our legacy PBX is not inherently compatible with the SIP protocol. Depending on the type of PBX in your organization you may not need the gateway for the PBX to connect to the Internet T1s. Also, you may not have clear cut instructions how to make the implementation work. I often joked that I was going to write a book on the topic because I had to draw from so many different informational sources to complete this implementation, I wanted an easier step by step guide that did not exist. Even some provisioning engineers at the NOC wanted my design.
In this implementation, we are using Internet T1s for our inbound 800 service and outbound long distance calling, integrating into a TDM-based PBX;as simple as that. There is a conversion from digital to analog and back. As noted, we are using SIP trunking with a PBX that does not inherently understand SIP, so the implementation needed to include a gateway to interface between the Internet T1s and the Analog signal expecting T1 cards in the PBX to carry the CO type signaling, including framing, clocking and line code to this PBX. We also opted to use two different carriers for the provisioning of the Internet T1 circuits for vendor diversification and to help mitigate against potential outages within one vendor's network.
I have found out many interesting details working with two providers, finding out that some sales teams are just not up to speed on their own company's services, let alone mixing types of services for a more custom approach as this type of conversion. I had to pull the plug on one vendor when I found out that we would have been the first company in Florida to use their service and did not yet have enterprise level references. I tried to convert two year ago with them, now I am using another vendor.
There were many challenges that were faced in this implementation. First off was carrier selection. The carriers have different types of SIP trunking, or business VoIP solutions available. You will need to find out what options work best in your situation. For ours, I wanted to have more control of our 800 numbers and call flow patterns personally. I have the ability to change routing options at will. There are different codec and sampling rates available. Based on your selection, you can receive different amounts of concurrent calls over the Internet T1. Security is a major concern for us at the bank; we need to pay close attention to keeping the gateway secure against unauthorized users. With the different carriers, there are different types of reporting available. You may need to create a custom report to share the information that is desired.
The ROI for this project was within two months. Our savings were in the change in transport method and competitive pricing. With the selected codec and compression from the SIP provider, for every Internet T1 that was turned up, two PRIs or T1s were removed. All inbound 800-traffic; and outbound long distance from the operations center come in and out of this gateway. Load balancing inbound and outbound with multiple failovers for each was designed. For improved total uptime, a second gateway was installed as a high availability failover, handling half of the original gateway's capacity. This high availability gateway is in full production as well. So the design had to be modified on both gateways to include proper load balancing and redundancy over multiple links and interfaces for both inbound and outbound calling.
All is working properly and management is happy. Now the planning has begun for the IP PBX conversion. We experienced some headaches along the way, but the ultimate success helped alleviate that pain. This was a very fun project!
