I am often asked the question, “What’s the best Session Border Controller?” To me, that is like asking, “What’s the best place to vacation?” It all depends on what you’re looking for. Do you want to lie on the sand on some tropical beach or is skiing down a mountain slope your idea of a good time? Do you want a four diamond resort or a rustic canoe trip through the Boundary Waters? The same goes for an SBC? Is this for your primary data center or a branch office? Are you looking to bring in hundreds of SIP trunks or thousands of remote SIP users? Is high availability at the top of your list of must-haves or are you willing to risk a few 9’s of up-time in order to save some money? So, as with vacation spots, the answer to “What’s the best SBC?” is once again, “It all depends.”
SBCs can be placed in several classes based on sized, functionality, and resiliency and it’s important to choose the SBC from those classes that best meets your needs. For the rest of this blog I will categorize the SBCs that I most often come in contact with in order to help you in the search for the product of your dreams.
Size Matters
Let’s begin with the size class. At the small to medium end I like the Sonus 1000, Avaya Portwell, the Acme Session Director SE/VME, and the AudioCodes Mediant 1000. These boxes range from 96 sessions on the Sonus 1000 to 500 on the Avaya Portwell. Between those you have the Mediant 1000 at 150 sessions and the Acme at 250. With the exception of the Acme which can be virtualized, all of these boxes come as an appliance. In fact, of all the SBCs I mention today, only the Acme Session Director is delivered as virtual software.
In the medium to large class I work with the Sonus 2000 (600 sessions), the Sonus 5100 (10,000 sessions), the Acme 3820 (8000 sessions), the Avaya SBCAE (2000 sessions), the AudioCodes Mediant 3000 and 4000 (1008 and 4000 sessions, respectively), and the Genband Q10 (6000 sessions).
The big boys of the SBC world are the Sonus 5200 (64,000 sessions), the Acme 4500 (32,000 sessions), and the Genband Q20 (18,000 sessions). It’s no coincidence that these SBCs are manufactured by companies that got their start in the carrier world.
There’s More
The next thing I think about is high availability. The SBCs that offer active / standby resiliency are the Avaya SBCAE, all the Acme products, the Sonus 5100 and 5200, the Mediant 4000, and both the Genband offerings.
Are you looking for an SBC that does both SIP and TDM? If so, you will need the Sonus 1000, the Sonus 2000, the Mediant 1000, or the Mediant 3000. All the other SBCs are SIP only and offer no support for analog or digital trunks.
After that I consider transcoding. Transcoding is the ability to convert from one Codec, or in some cases protocol, to another Codec or protocol. All Sonus boxes, the Mediant 1000 and 3000, the Acme 3820 and 4500, and the Genband Q10 support Codec transcoding. None of the Avaya boxes do.
The next big issue might be SIP endpoints. All SBCs will support SIP endpoints to some extent, but the Avaya SBCAE is the absolute best choice if you are looking to put Avaya branded endpoints outside your enterprise LAN.
Miscellaneous
Last are the odds and ends concerns. Do you want Lync survivability? If so, you will need the Sonus 1000, Sonus 2000, or Mediant 1000. Do you require JITC certification? If so, you need the Acme 3820 or 4500. How about hot-swappable power supplies and fans? I could go on with a number of other features and concerns, but the point is that all SBCs have their strengths and sweet spots. The Sonus 5200 is an extremely powerful SBC, but you would be crazy to buy one for a 20 trunk implementation. On the other hand, you would never use a Mediant 1000 for a large call center although it might be perfect for a branch office. Clearly, the answer really is, “It all depends.”
Tao, Zen, and Tomorrow 
There are indeed lots of good SBC options out there today. One perspective I see a lot from my companies is “we are interested in moving to SIP, but I am not sure we can take the risk of cutting over to SIP all at one time. What options do we have?” Keep in mind there are SBCs that can also function as a PSTN Gateway. This allows for a smoother, more gradual migration to SIP, and this can allow organizations to adopt SIP at their own pace. Further, there may be value for them in splitting their trunking between both TDM (keeping some of their existing DS3 or DS1 lines) and SIP trunks for a DR approach.
I agree. Some companies are ready to move immediately to SIP while others need a step by step approach. SBCs that begin their life as a SIP to TDM gateway before eventually becoming a “real” SBC is an excellent way to start.
[…] For a deeper dive, please read my articles on Practicing Safe SIP and Choosing the Right SBC. […]
Hello Andrew –
Your comment “All SBCs will support SIP endpoints to some extent, but the Avaya SBCAE is the absolute best choice if you are looking to put Avaya branded endpoints outside your enterprise LAN.” Can you provide an explanation as to why? We are planning to implement SIP and one of our top security guys prefer Acme over Avaya SBC, but we will have thousands of SIP endpoints that will reside outside our enterprise network. How is and Avaya SBC going to be a game changer in this feature compared to Acme SBC?
Hi Andrew, what do you think of Sangoma SBCs?
Unfortunately, I have no experience with them.
Do you know a good SIP SBC which runs on Windows OS? All I know is the SBC from Mizutech but it doesn’t have direct support for Lync. Something capable to 5000 simultaneous calls would be fine.
Sorry. I do not. The SBCs I work with all run on Linux (a much better choice than Windows).
We are going to migrate to SIP trunking a little at a time and looking at SBCs now – but why not continue to use the platform we have now for PSTN – ISDN and get a true SBC server and migrate services over slowly while testing……We have an Enterprise Avaya Aura – should we be looking at other SBCs other than AvayaSBCAE? as around 2000 sessions should handle our 160 locations and 12,000 IP phones.
Migrating over time is fine. I can’t recommend an SBC without really understanding your requirements, but if you are talking basic SIP trunks, all the leading vendors (including Avaya) will work for you. If you want to talk further, feel free to email me.