Are all SBC solutions equal? Absolutely not.
Session Border Controllers (SBCs) have seen unprecedented growth over the past five years from the rise of SIP trunking, IP peering, VoIP security issues and other factors related to the growth of IP-based communication services. Although the market is in a bit of a lull right now, increased penetration rate of SIP and Voice-over LTE will create another wave of growth for SBCs over the next five years. Because of this, the market for SBC vendors, or at least vendors claiming to be SBCs, has exploded accordingly.
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Are all solutions equal, though? My answer to that is a resounding “no.” I think there are many vendors that claim to be an SBC to try and leverage a hot market or to gain an entry into the space, but they’re not SBCs. From the research I’ve done in this space, here’s my criteria of what makes an SBC.
- It’s an all-IP element. In my mind, this is one of the biggest factors to defining an SBC. There are plenty of products with TDM interfaces and line cards in them that claim to be SBCs but, in my opinion, these are actually gateways, not border controllers. This is similar to the early days of IP PBXs where legacy vendors were trying to claim that IP-enabled PBXs were IP PBXs for market share purposes, but those products were really just legacy devices with IP interfaces. Similarly, simply terminating a SIP session does not make an SBC. The product needs to perform many other functions post-termination.
- Back-to-back session management. The product needs to have the ability to terminate a session and then re-initiate it for packet inspection and manipulation purposes. This makes it possible to read encrypted traffic, decrypt and then re-encrypt the packets.
- A range of session management services. An SBC needs to provide security, quality of service, interoperability and a wide range of other functions. There are many products that provide a single or a couple of functions, but not the whole range. Video border proxies, SIP trunking termination, E-SBCs and VoIP firewalls are useful products but they’re not session border controllers.
- A stand-alone product. This has been one of the more interesting discussion points in the industry. Will the SBC functionality be rolled into another product like a router or IMS solution? In fact, recently Mizuho equity analyst Joanne Makris was quoted as saying that SBCs see “fierce competition in the market from IP multimedia subsystems.” I couldn’t disagree with this statement more. This trend has been talked about for years with many other telco specific functions, such as security. However, for a number of reasons, including division of responsibility and points of failure, most telcos prefer discrete devices. Also, IMS systems are used in the core of networks where SBCs are used primarily at the edge, so I’m not sure how these things would integrate together anyway.
Lastly the SBC needs to have a tight relationship between the signaling and the media. There are numerous media gateways and other similar devices that provide either media control or session control, but to be a full SBC, the product needs to do both.
As communication continues the rapid march to end-to-end IP the session border controller will play an increasingly important role. As this happens, it’s critical that buyers of the technology and the market understand what an SBC is and what it isn’t to allow the IP communication environments to scale with the necessary quality, reliability and scale.
