SBC vs. SIP Server – What is the difference?

by Alan Percy, Senior Director of Product Marketing at TelcoBridges

The question came early and often during our participation at Astricon 2018 in Orlando.  “What’s the difference between an SBC and a SIP Server like Kamailio or OpenSIPs?”   Reminding us that in our world of telecom jargon, sometimes we need to stop and explain what we are talking about.

Let’s step back for a moment to look at the big picture.  When deploying SIP-based applications like Asterisk or FreeSWITCH, at some point, there is a need to divide the call load amongst multiple servers (physical or virtual).  Possibly because of traffic or simply to hedge bets against outages from a server crash, spreading traffic across multiple physical servers is a wise strategy.  The next challenge is routing incoming traffic from one or more service providers to those SIP applications.  Both SIP servers and SBCs can route traffic based on a range of programmable criteria including: dialed number, originating number, randomly, round-robin, availability and more.

Both SIP Servers and SBCs can also handle some of the interoperability and security services, but this is where the differences start to be more apparent.

So, what is an SBC and how does it differ from a SIP Server like Kamailio or OpenSIPs?

The simplest explanation is – SIP Servers manipulate and route SIP messages, never touching the media path.   However, SBCs broker SIP messages and media, acting as an intermediary between two networks, applying complex manipulations, security and routing rules on both the signaling and media.

SIP Server Functional Architecture

SIP message and media brokering within an SBC is accomplished via a Back-to-Back User Agent (or B2BUA for short), essentially terminating the SIP session on one network and re-initiating a new session on another network.  This can be between a WAN and LAN, between two WANs or two LANs.   The most common use case for SBCs puts them in the DMZ, putting one side on the WAN and the other side on a private (and secure) LAN with SIP applications (Asterisk, FreeSWITCH or other) on the protected LAN.  In this role, the SBC protects and distributes the traffic load across the various SIP applications.

Session Border Controller Functional Architecture

Using a B2BUA is more resource intensive than a simple SIP Server, but this is balanced by the additional functionality and security provided.

Beyond greater control over security policies, SBC’s B2BUA capabilities have other benefits, including:

  • Real Topology Hiding – of both SIP messages and media, ensuring the internal network topology of your network is not exposed to the outside world.
  • DOS and DDOS Protection – Intelligent security that stops DOS attacks in their tracks before they can get into your network.
  • Registration Flood Detection and Protection – preventing “network probing” and attempts to overload Asterisk servers with bogus registration attempts.
  • Media conversion and transcoding
  • Advanced call routing and traffic management capabilities across multiple networks.
  • Multi-application support – distributing and adapting SIP traffic between dissimilar applications from different vendors.

Beyond that, there are many other reasons to use commercial SBCs like FreeSBC for scaling Asterisk and FreeSWITCH implementations:

  • Ease of configuration – with FreeSBC’s easy to use web portal, there are no cryptic script languages to learn!  Most configurations can be completed in a few minutes with a web browser.   Want to see how it’s done?  Take a tour of the web portal and learn how to configure FreeSBC for SIP Trunking on YouTube at:   https://youtu.be/GvfKSw1H6gU
  • Low cost subscription-based pricing that allows “pay as you grow” $1/session/year/server for FreeSBC Pro Edition
  • Carrier-grade – with scaling up to 60,000 sessions per server with 1+1 redundancy for High Availability
  • Platform choices – with versions for bare-metal, VMware, KVM and Amazon AWS
  • 24/7 Technical support availability
  • Regular software updates without having to wade through forum recommendations and Github branches

Understanding the difference between these two important network elements gives network designers the tools to build more efficient and secure solutions.

You can learn more by attending the upcoming webinar “What is an SBC?” at:  https://www2.telcobridges.com/WhatIsAnSBC

Download your free evaluation copy of FreeSBC TODAY at: www.FreeSBC.com

 

The State of Robocalling – a discussion with Eric Burger, FCC

by Harry Wakefield, Marketing Communications, TelcoBridges

TelcoBridges executives were in Chicago this week for the 2018 IIT RTC Conference and Expo. Our own Alan Percy sat down and recorded a podcast with FCC Chief Technology Officer Eric Burger, discussing one of our favourite subjects, robocalling fraud and actions the FCC is taking to protect consumers.


Listen at: https://youtu.be/nUTA2m1Chnk

Our conversation touched on several aspects:

  • how it’s the #1 consumer protection issue right now for the FCC
  • it’s also personal, Mr. Burger’s phone actually rang with a robocall during his presentation! (not planned)
  • says he, it’s a “real problem with real impacts”
  • how to handle fraudulent robocalling vs legitimate uses by automated dialling systems
  • neighbourhood spoofing and related legislation
  • recent actions by the FCC including very large fines
  • the more than $200 million dollars in fines levied so far this year (a record)
  • new technologies that can help like STIR/SHAKEN
  • a progress report on that technology
  • the parts, the goals, and the implementation of STIR/SHAKEN
  • the roles of the vendors and carriers and a timeline for the deployment
  • and last thoughts, “there’s hope!”

Learn more about STIR/SHAKEN during a webinar TelcoBridges hosted with TransNexus at: https://freesbc.telcobridges.com/video-library/#Robo

Battling Robocallers – Round 3

by Alan Percy, Senior Director of Product Marketing

This last month, a telemarketing firm hawking health insurance was fined $82 million for their role in 21 million illegal unsolicited robocalls.  Are the legal consequences enough to put an end to the nuisance calls?

As reported by the Washington Post, the Federal Communications Commission imposed an $82 million fine against a telemarketer who made more than 21 million unsolicited calls to consumers to try to sell health insurance and generate leads.

Despite this stiff penalty against one firm, the phones of Americans continue to ring with offers of bogus credit card protection offers, free vacations and fake IRS scams.

A root of the problem is the ease at which bulk phone calls can be made with spoofed caller-ID information, tricking unsuspecting victims to answer call they think are from friends or neighbors.  While there are legitimate reasons to substitute caller-ID information (Doctors office reminders, school notifications, etc) fraudulent abuse continues to be an industry-wide problem.

Meanwhile, progress is being made in the standards bodies with further refinement of the STIR/SHAKEN framework that will allow service providers to “certify” that the originating caller and communications service provider owns the rights to the calling number.

In August, the ATIS and SIP Forum announced the release of two key specifications needed to standardize the user experience and APIs needed for implementation of SHAKEN.  The first specification Technical Report on a Framework for Display of Verified Caller ID (ATIS-1000081) defines a standard user experience for calls from known callers, likely SPAM callers, suspect and potential fraudulent callers with color icons and information on screen-based devices.  The second specification Technical Report on SHAKEN API for a Centralized Signing and Signature Validation Server provides a proposed RESTful API for the implementation of the SHAKEN specification

This next couple weeks will see two industry speaking sessions addressing the issues, including:

Battling Robocallers – a Tutorial on STIR/SHAKEN presented by yours truly at Astricon in Orlando on Tuesday, October 9th at 10:00 AM

Comprehensive Approach to Illegal Robocalls presented by Eric Burger, CTO at the Federal Communications Commission at the Illinois Institute of Technology Real-Time Communications Conference on Tuesday October 16th at 9:00 AM

Later in December, the SIPNOC event has a dedicated Robocall Summit track specifically addressing the problem, including a number of industry thought leaders.

However, questions do remain on the timeframe and motivation of the service provider community as to when they plan to implement any or all of the recommendations, giving consumers a break from the fraudulent robocallers.