Change in IT Practice

Unless there is a Private Branch Exchange (PBX) that already handles the telephony within an established company, a contemporary IT team would not include architecting or managing such a system as part of their core competence. Instead, the team probably leases a bundle of Digital Signal 0 (DS0) lines from the local telephone company and internally sets-up a voice-over-IP (VoIP) network. Calls take the form of packet-switched voice data relayed through a core QoS-enabled switch between endpoints outside the internal network and VOIP phones on the edge of the internal network.

 

What's at the Other End of the Voice-Over-IP Phone?

VOIP phones have a switch port to which the end user can connect a desktop computer, so that behind any VoIP phone there is commonly at least one other device using a separate DHCP lease; and the phone and the device(s) connected to its switch port are treated as directly connected to the network switch. If the device connected through the phone's switch port is a hub, then there may be as many as 6 devices using different DHCP leases. Or, connect a wireless controller to the phone's switch port and a number of wireless access points and SSIDs may be running behind that particular VoIP phone.

 

Monitoring a VoIP-integrated edge network can be challenging in at least two ways: seeing reliable topology information (what is connected to what and at what remove) and seeing devices in terms of their Layer2 (data-link; for example, MAC) and Layer3 (network-link; for example, IP) relationships and activity. Lacking views into these aspects of your network can limit your ability to investigate or troubleshoot unusual events or trends that impact the call quality that your  Quality-of-Service (QoS) monitoring tools (measuring latency, jitter, etc.) are showing you.

 

Since a VoIP network almost always serves other networking purposes within the business you usually cannot resolve disruptions by simple exclusion (for example, of traffic from specific domains like youtube.com).

 

Ports of Call

Applications that monitor your VoIP implementation for call quality (latency, jitter, etc.) usually do not track device port connections. So you may see the results of the staff breaks that involve executing World of Warcraft maneuvers through your network but you won’t be able to figure out who is behind those bursts of bandwidth use that are wreaking occasional havoc on the sales team’s ability to use their phones.

 

Effectively analyzing network events impacting VoIP QoS requires an ability to correlate switch ports with user login data, MAC and IP address bindings, and traffic activity.  SolarWinds User Device Tracker (UDT) is a tool that offers exactly these correlations. Explore its resources in this live demo; and see the administrator's guide for detailed information on how to get things done with UDT.