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VoIP and video services: Understanding network architecture and design

VoIP and video services are climbing in popularity. Learn how network architecture and design can help you provide these services to your clients.

Service provider takeaway: Service providers will learn how network architecture can affect the implementation of video and VoIP services.

With the rising popularity of video and VoIP services, it's important to know how providing these services might affect your customers' networks. James McCabe, author of Network Analysis, Architecture, and Design, sat down with to discuss the importance of network architecture and design when implementing VoIP services. Network architecture and design help you determine the need for these services in the network and the impact on existing services and network functions (e.g., routing, performance, management and security), as well as helping you as a service provider make the technology and topology choices for your client's network to support such services.

Q: What is the need for video or VoIP services in the network?
McCabe: People have been trying to integrate voice and video along with data for the last 15 years, ever since the advent of asynchronous transfer mode (ATM). One of the purposes of this was to provide media convergence.

There are a number of reasons why you would want convergence of voice, video and data. There's the economy of scale, the ability to put all services into the same media, the ability to control the services with the same mechanisms, plus the cost savings.

Q: How can voice and video impact existing services and network functions?
McCabe: Bringing voice and video into an existing or a new data network can often have subtle impacts. When you bring voice and video into a data infrastructure, they become reliant on the data infrastructure. There are implications that the enterprise needs to understand.

When the data network has a problem, it could have unintentional consequences on voice and video. Voice and video now depend on several things: the data network itself, the hardware, the software, the protocol and the quality of service. All of these can impact voice and video quality.

My book attempts to understand the need for the service. In a lot of cases, people don't do that. Some people think about video and VoIP services as being exciting and new and they'd love to have it, but without knowing if they need it. People should understand whether or not they really need it. Whenever you make a major change like going to VoIP, there are trade-offs like having the economy to scale, the cost savings of bringing them together and the dependencies of those services on the data network. As you start to understand network architecture and design, those trade-offs become better understood.

Q. How do video and VoIP services affect routing security and network management?
McCabe: The routing protocols may need to accommodate quality-of-service mechanisms to allow voice and video to have higher priority over data services. Your network management needs to have hooks in it so that you can monitor it and resolve problems that are related to voice and video.

Security has to be modified to accommodate voice and video flows through this network. There are definite impacts of having new services in the network and as a result, the traffic flows impact all of the other functions of the network.

Q. What would one do to ensure a smooth implementation?
McCabe: I try to look at things from a traffic flow perspective. All applications and services generate traffic flows through the network. All of the functions of the network (security, network management, routing, addressing, performance), those are all impacted on traffic flows. I look at where the application is going to be provided, what kind of traffic flow is going to be generated and what will need to be done in those various functions to accommodate those traffic flows. I need to make sure those traffic flows don't have a negative impact on the other traffic flows and their services in that network.

Q: What is the channel opportunity when it comes to network architecture for video and VoIP services? What should service providers be wary of?
McCabe: Channel partners have the opportunity to understand the architecture and design of a network and modify it to accommodate new services. Third parties can come in and provide a view into the network regarding architecture and design for the integration of new services.

What we want to avoid is for someone to come in and say, 'We want to provide a video service on your network,' and all they focus on is that service. That video service impacts the rest of the network, and if they don't understand the consequences and what mitigates them, then all they're doing is causing a larger problem elsewhere in the network. In many instances, I've seen people do something to a network in order to achieve a certain result, such as a service user or app, and ending up negatively impacting that network in other areas. In understanding architecture and design, we try to avoid that.

Video can take a lot of bandwidth, and voice is very sensitive. You want to make sure the network is architected and designed to accommodate that in the context of the application beyond that network.

Q. Is it the kind of thing where a provider can launch and walk away? Is there maintenance involved?
McCabe: This depends on what that enterprise has in terms of their own internal resources. A third party could implement this and walk away if the enterprise then has the ability to take up the management. Some environments have that ability, but some don't. What you don't want to do is to implement and then walk away with nobody having the ability to monitor, manage or support that service.

When it comes to introducing a service, voice, video or anything, an enterprise really needs to understand their need for the service. Understanding your need for the service sets the stage for developing an architecture which helps you determine how that service is going to impact -- complement or detriment -- the rest of the enterprise. That lets us determine if we need to implement more security, more storage, a different set of computing functions, etc.

Network architecture sets the stage for these kinds of decisions, which will become the design. Going into a specific router to make a specific change to support the service will become part of the design. This all makes logical sense, but it's surprising how many enterprises will rush to the solution and end up with complications. The right way to go is to understand what you need, how it's going to be impacted and how to support that in your network. In practice, people are much happier going through that practice than going through and implementing VoIP services blindly.


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