A session border controller (SBC) is not required for a WebRTC gateway. That might be a strange statement considering most of the industry has assumed an SBC is necessary for successful WebRTC scenarios. Why would the industry make that mistake? Because an SBC is basically an IP-to-IP translation node, and the WebRTC and SIP worlds are both in the IP realm. So, it’s natural to assume that in order to properly handle WebRTC services, one must leverage the SBC’s IP fluency.
But let’s look at the core functions of an SBC. A key function of an SBC is SIP interworking. It’s good at translating one version of SIP to another version of SIP. My SIP is not always your SIP. And it’s always going to be like that, so SIP interworking will always be required. But as you see from the picture below, WebRTC signaling is not typically SIP. The signaling is from the Web realm. So, the key function of the SBC being a SIP interworking node is not really at play, is it? You don’t need an SBC to be the base of a WebRTC gateway.
Let’s take it another step further. Another key function of an SBC is to provide NAT traversal. In other words: protect the border, yet provide secure traversal. WebRTC provides inherent NAT traversal. So this key function of the SBC is also not really all that useful in providing a WebRTC gateway. Again, this demonstrates you don’t need an SBC to be the base of a WebRTC gateway.
Put those two together and you conclude rightly that you don’t need an SBC if you want a WebRTC gateway.
So what do you need for a WebRTC gateway? Well, the media plane transport is essential, as is transcoding. This can be provided by a software-based media server. You also need signaling conversion, what is referred to as H2S (or HTTP to SIP) signaling. But that is not necessarily an SBC. It can be a software module that does that conversion but has nothing to do with, nor necessarily needs to have any roots from SBC land.
You don’t need an SBC for a WebRTC gateway. The industry needs WebRTC gateways to support transcoding and signaling conversion, but they don’t necessarily need to be supplied by SBC vendors.
Want to know the best practices for getting the most out of WebRTC? Check out this WebRTC Best Practices slideshow and ask us your questions.