Preparing Your Data Network for Voice and Video
Videoconferencing has become a popular way for organizations to communicate. However, the high-definition audio and video used by videoconferencing can place huge demand on a network. Many organizations have embraced the technology without knowing whether their network can support it, resulting in poor network performance and unexpected down times.
Polycom, a multinational telecommunications technology provider, released a whitepaper describing how to prepare IP networks for voice and video traffic. We’ll explore some of these techniques and how they can help prepare your own organization’s network for high-definition videoconferencing.
Voice and Video Pose Unique Requirements
Compared to normal network traffic, videoconferencing is highly demanding. Video in particular is extremely bandwidth-intensive, using anywhere from 256 Kbps for standard-definition to 4 Mbps for high-definition. Additionally, any interruptions while transmitting audio or video will cause a noticeable drop in call quality, whereas a document or email can be resent without issues.
Determining Your Requirements
To estimate the demand on your network, you should first determine the level of traffic that voice and video will create. Start by answering the following questions:
• What quality level will users need?
• What are the capabilities of the end users’ devices? Do they support high-bandwidth networking?
• Will most of the traffic originate from a few central locations (e.g. conference rooms) or from many distributed locations (e.g. desktop or workstation computers)?
• How many devices will be transmitting over a single switch or bridge simultaneously?
The answers to these questions will determine how you should begin optimizing your network.
The steps to preparing your network for voice and video data fall under three key categories: prioritizing data as it travels through the network through Quality of Service (QoS), reducing demand on the network through compression, and increasing the capacity of the network by adding bandwidth.
Set Quality of Service Standards
Quality of Service (QoS) is a set of rules used by network devices to determine how different types of data should be treated. QoS can give audio and video traffic priority over normal traffic, preventing call quality from suffering as a result of normal traffic.
A key factor of data networks is that they have to accommodate large bursts in data. During peak use, networks can serve up to 10x the amount of bandwidth as normal use, causing slow downs and potential data packet loss. In cases of congestion, QoS gives priority to real-time streams, preventing jitteriness or latency. QoS can be applied to internal Local Area Networks (LANs), external Wide Area Networks (WANs), and various types of networks such as WiFi.
Shrink the Size of Voice and Video
If you can’t increase the capacity of your network, reduce the size or number of streams. The most direct way of doing this is to manage call volume. By limiting the number of concurrent video calls, you can easily manage the strain placed on your network.
Another option is to shrink the amount of bandwidth used by video traffic through data compression. Scalable Video Coding (SVC) is an extension for H.264 that automatically lowers the size of a video by reducing the frame rate, resolution, quality, or any combination of the three. Some WAN optimizers offer their own compression techniques for further reducing the size of data packets.
Improve Connections Between Locations
Connecting multiple locations in an organization is typically done through a Wide Area Network, or WAN. WANs pose a unique challenge for voice and video, since they have to provide high bandwidth and low latency over potentially global distances. As a result, many service providers offer Multiprotocol Label Switching (MPLS). MPLS is a form of QoS that works by assigning labels to data packets. Network devices determine how to treat a packet by reading the label. This helps the network route packets without having to understand the actual contents of the packet.
For smaller-scale networks, metropolitan-area networks (MANs) connect locations within a city or greater metropolitan area. Many MAN Ethernet providers offer technologies that support high bandwidth traffic, particularly voice and video. Combined with QoS, MAN Layer 2 connections can easily support high-definition videoconferencing.
If your organization has a limited network infrastructure, you can always fall back to the general Internet. The benefit of streaming over the Internet is that the connection is easily accessible by all parties. The downside is that you have no control over the connection. Not only is the transmission more susceptible to latency and bandwidth issues, but it’s also more susceptible to interception from a third party.
One alternative that many organizations use extensively is a Virtual Private Networks (VPN). VPNs create secure tunnels between an organization’s internal network and external computers, such as take-home laptop. VPNs use encryption to secure connections from eavesdropping, but this creates a high overhead. The difficulty in transmitting real-time, high-bandwidth data over a VPN could make voice and video difficult if not impossible.
At Layer Seven, we understand data networks and network performance. Give us a call at 619-473-5600 or simply contact us. We'd be happy to see how we can help!