A firewall is a vital component of any enterprise network. But, it can also wreak havoc on the operation of VoIP implementations. In this article, we address the most common problems a firewall can introduce to an IP telephony network, as well as best practices for avoiding or remedying them.

Part 2 of 2

When it comes to VoIP signaling, SIP is by far the most widely-used protocol. But, there are other protocols, as well, and being familiar with them is helpful when establishing interoperability between systems or deploying specialized installations. In this article, we’ll discuss the H.323 protocol suite and the media gateway control protocol (MGCP), and look at applications for which they are best suited.

IP Telephony features are not always “plug-and-play.” Rather, they must be configured to function properly. This is equally true when dealing with quality of service (QoS) on a network that transmits both data and voice (i.e., a converged network).

Companies commonly find that when they install their VoIP system on a preexisting data network, it works great at first. Days or weeks later, however, users complain of poor voice quality and intermittent disconnections. The network has not changed, so what’s going on?

In this article, we’ll see why QoS is a fundamental part of your network design for voice, and examine five configurations that should always be employed to achieve high-quality voice on a converged network.

Your customer using a legacy phone system decides to switch to voice over internet protocol (VoIP). They install an IP PBX and buy some IP phones. Great, they’re all set, right? Wrong. Without configuring their data network for quality of service (QoS), they will experience a severe deterioration in voice quality and may regret making the decision to switch. Yes, the IP PBX and the IP endpoints will already be configured for QoS. But what about other parts of the network like the pre-existing routers, switches and firewall? All it takes is one missing link for the whole system to be compromised.

QoS is a big topic. In this article, we’ll look at two main approaches to QoS: IntServ and DiffServ, their strengths and limitations, and when to use which one.

Over the past few weeks we’ve looked at different ways to structure multisite VoIP deployments. The truth is, each business is unique and sometimes a customized architecture is needed. In this article we look at a hybrid solution. A hybrid call processing deployment allows you to craft a solution that is perfectly tailored to a specific customer’s needs.

Last week, we discussed centralized call processing and its benefits and potential pitfalls. In this article, we’ll examine another type of telephony infrastructure design for multisite enterprises: distributed call processing.

Enterprises with multiple sites have a variety of options when it comes to their IP telephony infrastructure. Which setup will best meet their needs depends on the answers to questions such as:

• Where should the call processing take place?
• Where should calls to the PSTN exit the network?
• Where should incoming calls connect to the corporate network?

These decisions depend on the nature of the underlying network infrastructure that will carry the IP telephony services, as well as other considerations such as the location of the remote sites, the dial plan, and cost.

In this article, we discuss the centralized call processing model and how to avoid common complications with its deployment.

Implementing telephony solutions in an enterprise environment can be daunting. The level of difficulty and complexity usually escalates with the number of end users. Implementing a telephony solution in a multisite environment takes the complexity to a different level altogether.

In this article we offer up some tips for streamlining the implementation of a multisite VoIP deployment so the company can derive the maximum benefit from the solution.

Product Review

Netgear, a company with a heritage spanning over 22 years (an eternity in the telecom market), is steadily gaining prestige and recognition for the quality of its products and their attractive quality/price ratio (QPR). 

In this article we review Netgear's Insight Managed Gigabit Ethernet/10G SFP+ Smart Cloud Switches, which are incredibly feature-rich considering their affordable price point!

...Especially if they have lousy internet service

Because of its name, most people think of SD-WAN as being relevant only for companies with multiple sites. But SD-WAN can do wonders for many types of companies – even a single-site business located in a remote area with an unreliable internet connection. If you work with a company that fits this description, SD-WAN can resolve a lot of their VoIP issues.