Tips

An introduction to SIP verbs: Register, subscribe, invite

Part 2 of a three part series on the Session Initiation Protocol, this article discusses commonly used SIP codes and response verbs, and explains basic SIP operation. Continue Reading
An introduction to SIP and SIP functions

The Session Initiation Protocol (SIP) is the primary protocol that's used by most VoIP and unified communications (UC) products. This is part 1 of a three-part series that will explain how SIP works. Continue Reading
Understanding presence technology

Presence technology is an integral part of unified communications, making it possible to locate and identify a device or user wherever it might be. Learn why presence is important. Continue Reading
Open source PBX: Risk or value?

Open source IP PBX systems like Asterisk have benefits and risks. Learn what they are and assess your readiness for the IP PBX implementation in this tip from Gary Audin. Continue Reading
VoIP security -- Free IP telephony fuzzing tools

Protect your organization's VoIP security with free VoIP security tools designed to test IP telephony vulnerability. Continue Reading

Routing basics -- What VoIP managers need to know

Voice over IP (VoIP) requires that an organization's voice staff understand many of the fundamentals of data networking. Routing is an essential data networking function that also applies to VoIP. In this tip, learn more about the routers and ... Continue Reading
VoIP traffic: Five steps to prepare your network

VoIP traffic is much more sensitive to latency, jitter and packet loss than most network applications. It is crucial that you ensure that your network is ready to handle this new demand. Continue Reading
How silence suppression saves WAN bandwidth

Silence suppression, or voice activation detection (VAD), technology is used to save WAN bandwidth used by VoIP traffic, while comfort noise generation (CNG) counteracts negative affects on VoIP speech quality. Continue Reading
IP PBX: Ten reasons to switch

Should you throw out the old PBX and replace it with a new IP PBX? This tip from WindowsNetworking.com provides ten compelling reasons to do so, along with a brief explanation of what an IP PBX is, how it works in a computer network and how it ... Continue Reading
VoIP bandwidth: Calculate consumption

The bandwidth needed for VoIP transmission depends on compression technology, packet overhead and the network protocol used. In this tip, learn how to calculate how much bandwidth your VoIP implementation will need. Continue Reading
VoIP bandwidth -- Rightsize your WAN for voice traffic

Up-front rightsizing and WAN bandwidth capacity planning are critical aspects of VoIP, and should be done prior to deploying an MPLS network or implementing VoIP. Continue Reading

How voice compression saves bandwidth

Compression of voice traffic can save bandwidth on your IP network, but can cost quality or cause delays. Learn more about the CODECs or standards for voice compression -- and their effect on call quality -- in this tip. Continue Reading
What's in a VoIP packet -- An introduction to bandwidth for VoIP

Learn what makes up a VoIP packet, how headers work, what protocols transport voice traffic over the Internet and how this traffic uses network bandwidth. Continue Reading
VoIP management tools: Calculating ROI

Before purchasing management tools for VoIP, you may need to calculate the return on investment (ROI) to justify the cost of those tools. In this tip, Gary Audin explains how to calculate ROI and provides specific checklists for calculating the ROI ... Continue Reading
VoIP maintenance: Creating a schedule for patches and upgrades

VoIP systems fall under the same type of maintenance guidelines as other networking equipment. In this tip, learn guidelines and best practices for scheduling your VoIP systems maintenance. Continue Reading
Why you need to learn VoIP for your Cisco certification

Because of the increasing importance of VoIP and Cisco's growing emphasis on it, the networking giant has increased the significance of VoIP in its certification exams. In this tip, David Davis looks at the VoIP focus in popular Cisco certifications... Continue Reading
VoIP traffic encryption tools

Securing VoIP traffic remains one of the biggest obstacles to its mainstream enterprise use. VoIP traffic tends to be unencrypted, but that doesn't mean that it has to be. In this tip, Brien Posey explores various options for VoIP encryption, ... Continue Reading
VoIP services overview: Defining VoIP terms

The vast majority of conversations about the convergence of voice and data could benefit greatly from a generally accepted vocabulary. The primary culprits in this smorgasbord of confusion are the terms "VoIP" and "IP telephony," which are used ... Continue Reading
TFTP servers for testing IP phones

Testing a software upgrade on a single IP phone can present a challenge. In this tip, learn how to implement your own TFTP server for testing your phones' configuration information. Continue Reading
Five VoIP security recommendations

Before beginning a successful VoIP rollout across your organization, there are several things you should consider. Continue Reading
SIP interoperability and testing

Session Initiation Protocol (SIP) is a signaling protocol typically used for telephony, instant messaging and Internet conferencing. This article discusses the interoperability and testing being done to support this protocol. Continue Reading
CDP and multi-vendor networks don't mix

Cisco switches and CDP go hand-in-hand, but when non-Cisco switches and CDP meet, interesting things happen. Continue Reading
Defining traffic telecommunications style

There are three types of traffic: voice, data and image -- each with its own set of requirements for transmission. Find out here how these different types of traffic are quantified. Continue Reading
Turning analog phones into VoIP phones

How an ATA or broadband phone works and what kind of features and performance you can expect from them. Continue Reading
IP telephony implementation planning

Expert advice breaks down a successful IP telephony implementation into two distinct and easy to understand steps. Continue Reading
Working with the Layer 2 data link layer in an IP telephony deployment

This IP telephony deployment article provides solutions to performance issues in Layer 2, the data link layer. Continue Reading
Learn IT in 10 easy steps: VoIP

This handy guide to VoIP provides you with an overview of the technology, including key terms, trends, challenges and more. Continue Reading
System components of VoIP

This is the second tip in a series excerpted from a report by Ohio State University. The report analyzes issues and challenges in the evolving VoIP technology. Continue Reading
Policing and shaping within QoS

Learn about the policing and shaping methods within QoS that allow IT professionals to smooth traffic flows for VoIP transmission. Continue Reading
DHCP for VoIP

Learn how to set up DHCP for Voice over IP (VoIP) in this article. Continue Reading
Don't forget to use multicast

The benefits of using multicast. Continue Reading
Survivable remote site telephony

Fault-tolerant telephony solution for smaller remote sites. Continue Reading
A case of the jitters

Testing for specific problems affecting VoIP. Continue Reading
Watch out for asymmetrical routing

Asymmetrical routing can cause trouble that's tough to diagnose. Continue Reading
Enable the hookflash relay

How to enable it. You'll need it. Continue Reading
VoIP user experience questionnaire

VoIP user experience questionnaire Continue Reading
Tune spanning tree for VoIP

Tuning settings to account for the vagaries of spanning tree protocol. Continue Reading
Testing VoIP connectivity on IOS

An undocumented command that makes testing easy. Continue Reading
Private line automatic ringdown

How you can connect two phones to one another exclusively via VoIP. Continue Reading
Check for full duplex capability

How to find out if hardware supports full duplex record and playback. Continue Reading