Why do Enterprises Favor Centralized SIP Trunking Topologies?
Distributed or centralized SIP trunks? This is a key question for many large distributed organizations contemplating the move from TDM to SIP trunking access services. There is no doubt that SIP trunking saves money, increases business agility and provides access to a wider range of services than TDM trunks. The question is: Which SIP trunking topology is best for organizations that do business in multiple locations?
Recent research by Acme Packet indicates the market favors centralized SIP trunking topologies. We blindly surveyed over 100 medium to very large enterprises in the US and Europe and learned nearly 60% are planning or implementing a centralized SIP trunking topology. This is no surprise because organizations save the most money when they use their private data network to backhaul traffic to a central location, such as a data center. This topology reduces the number of SIP trunks that must be leased from service providers, simplifies operations and administration and enables better policy control.
Forrester Consulting estimates a 401% ROI for a typical large organization that deploys a centralized SIP trunking topology using Acme Packet E-SBCs. The Total Economic Impact of Acme Packet’s Session Border Controller, which is based on separate and independent research by Forrester, indicates organizations save by eliminating underutilized TDM trunks serving each location as well as lower per-minute rates that apply to VoIP usage. In fact, each of the customers that Forrester interviewed reported a 40%-60% reduction in monthly service fees upon replacing T1/E1 TDM trunk lines with SIP trunks. Obviously, savings is directly proportional to the number of TDM trunks eliminated.
Although there are significant benefits to centralized SIP trunks, there are also many good reasons for sticking with a distributed topology. Approximately 40% of the companies in our survey were planning or implementing distributed SIP trunks and nearly all of them said they had an IP PBX installed in their remote sites. For these companies, swapping a TDM trunk for a SIP trunk through the incumbent service provider in each location is easier than rerouting traffic to a central data center, transferring many DIDs to a new service provider and normalizing feature groups. They can realize many of the same business agility and efficiency benefits of SIP trunking, albeit with a somewhat lower financial pay-off.
Additional reasons cited for sticking with the distributed topology include:
- IP/MPLS VPN does not reach all remote locations or doesn’t provide the requisite QoS
- Country-specific or jurisdictional requirements to maintain local PSTN connections
Survivability and latency are additional considerations when choosing a topology. Organizations that have stringent requirements to maintain local site PSTN connectivity may need to maintain local SIP trunk connections. This requirement has eased considerably in the current age of the cell phone. Generally, the latency added by centralization doesn’t make a noticeable impact on voice quality so long as the backhaul traffic doesn’t cross continents.
All SIP trunking topologies require an E-SBC be deployed in each location where a service provider trunk is terminated. The E-SBC protects communications from security threats and ensures interoperability with the trunking service. Our survey found the majority of organizations prefer to standardize on a single vendor for the communications infrastructure across data center and remote locations. This enables them to simplify everything from purchasing to operations and administration. Acme Packet offers software-based E-SBC models that can be deployed on VMware ESXi, Microsoft HyperV or dedicated x86 server platforms, providing enterprises a cost-effective solution for smaller distributed locations. These software-based E-SBCs complement the capabilities of our larger appliance products.
A hybrid of distributed and centralized trunks may be the optimal choice for many organizations, enabling them to tailor services to the needs of each location. The hybrid approach also decouples the adoption of end-to-end IP communications services from longer term data center consolidation projects. It provides access to IP-based services across the organization while enabling migration to a fully centralized topology.
There is no “wrong answer” when choosing between centralized, distributed or hybrid SIP trunking topologies. Each provides cost savings, business agility and other benefits over TDM trunks. The imperative for most organizations is simply to begin adopting SIP trunks and position themselves to take advantage of the rich services they offer.
Biography: As the director of enterprise product marketing, Carl Blume is responsible for defining and developing market-driven solutions to support the company’s enterprise product line. Prior to joining Acme Packet, Blume held the position of Marketing Strategist for Hewlett Packard’s networking business unit and led the creation and execution of marketing programs to support HP’s successful acquisition of 3Com. Blume’s prior experience includes marketing leadership roles at Colubris Networks, a leading developer of wireless LAN solutions and Paceline Systems, a developer of InfiniBand datacenter networking solutions. Blume received a BS in electrical engineering, an MBA and has been awarded a United States patent.
Total Economic Impact of Acme Packet’s Session Border Controller
Forrester Consulting, a respected independent global research and advisory firm, has identified hard and soft benefits associated with deploying Acme Packet's E-SBCs. The data is based on independent interviews and analysis of six Acme Packet enterprise customers conducted by Forrester as part of a Total Economic Impact study commissioned by Acme Packet.