Introduction to Session Border Controllers

September 25, 2013 by Christopher Isak 1 Comment »

High definition video conferencing is a standard right now. If it will change, it will only change to an ever higher definition such as Ultra HD (involving 4K and 8K). Virtual workplaces, telecommuting and working from home becomes more and more easy and so organisations go expanding, sometimes forgetting about network requirements ending up with new capacity limits or reduced quality of their video communication solution.

A Session Border Controller can help with many problems there might be, but it is not a remedy for every issue ever to occur on your video conferencing network. I wrote this article to give you some more insight into what a Session Border Controller is, what it does and how it can help your corporate communication.

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What is a Session Border Controller?

A Session Border Controller is a network component designed to safely link networks with a different security requirement and setup. They are mostly utilised for VoIP and video conferencing networks to establish secure connection sessions. The Session Border Controller therefore allows control of signaling and transfer of media data in a secure way.

What can I do with a Session Border Controller?

Session management allows service providers to control the session routing, establish interoperability across environments with differentiating standards, enforce bandwidth policies or create an interface to a third party application. To keep it short and simple: A Session Border Controller optimizes solution performance and overall service quality, it allows a rapid service deployment or growth and it protects infrastructure from malicious attacks.

Who develops Session Border Controllers?

Based on Gartner’s Magic Quadrant for Session Border Controllers from October 2012, Acme Packet (recently acquired by Oracle) excels in execution as well as vision scope, making them the leader of the magic quadrant (see graphic). Other competitors are Huawei, Sonus, Genband, Metaswitch Networks, Dialogic, ZTE and Technicolor.

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Magic Quadrant for Session Border Controllers by Gartner Research

Acme Packet is very interesting due to their focus on unified communications networks and even offering solutions especially designed for video conference networks of manufacturers such as Alcatel-Lucent, Avaya / Radvision, Cisco (including former Codian / Tandberg technologies), LifeSize, Polycom and Vidyo. Supporting and enabling interworking these technologies the Acme Packet solution avoids potential for vendor lock-in, protecting the investment made in video conferencing infrastructure and endpoints.

What are the technical functions of a Session Border Controller?

The functional scope of a Session Border Controller can vary, depending on what the individual device is designed to do. However to reflect a maximum of capability information, we would like to list the following functions that can be found in Session Border Controllers:

Connectivity

  • IPv4 / IPv6 interworking
  • SIP manipulation
  • NAT traversal
  • VPN connectivity
  • H.323 / SIP interworking

Quality of Service (QoS)

  • Traffic policies
  • Call admission control
  • ToS / DSCP bit setting
  • Resource allocation
  • Rate limiting

Security

  • Defense against DoS attacks
  • Can prevent toll fraud
  • No topology hiding possible
  • Malformed packet protection
  • Signaling protection via TLS and IPSec
  • Media protection via SRTP

Media processing

  • DTMF delay and interworking
  • Media transcoding
  • Tones and announcements
  • Data and Fax interworking
  • Support for Voice and Video calls

Regulatory

  • Call prioritization (e.g. for VIP usage or emergencies)
  • Auditing functions for internal audit or for law enforcing organisation
  • Business Intelligence, reporting, management information, source for billing information

Summary

Even though not a mandatory part for VoIP or video conferencing networks, Session Border Controllers have a great potential to add value to the communication services of organisations. The relevance increases for service providers companies as the functions described above can significantly increase the quality and performance of a serviced network.

If you have questions, remarks or other types of feedback please drop us a line in the comment section below. Thank you!

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I write about topics like Telepresence, ITSM, Creativity and all that techie things you all love.
 
  • rajz

    fantastic read

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