Terry Slattery
Terry Slattery, is a senior network engineer with decades of experience in the internetworking industry. Prior to joining Chesapeake NetCraftsmen as...
Read Full Bio >>

Terry Slattery | January 01, 2013 |


The Twisted Path of Multimedia VDI

The Twisted Path of Multimedia VDI Monitoring and troubleshooting multimedia communications in a VDI environment is much more complex than in a peer-to-peer network model.

Monitoring and troubleshooting multimedia communications in a VDI environment is much more complex than in a peer-to-peer network model.

There is a big push in many organizations to move to Virtual Desktop Infrastructure (VDI). This brings a whole new level of complexity to deploying, managing, and troubleshooting multimedia applications. An audio and/or video application may be operating over multiple paths, each with different types of encoding and operational characteristics, as seen in Figure 1.

Figure 1: Multimedia VDI Communications Path

There are three major flows in each direction for a bi-directional multimedia session to function.

* Client A VDI path to VDI Server 1, using Client A's VDI protocol.
* VDI Server 1 to VDI Server 2, using the native multimedia streaming protocol.
* Client B VDI path to Server 2, which may use a different VDI protocol than Client A's VDI protocol.

In addition, the reverse direction for each of the above paths may be used if a bi-directional multimedia session is in use.

Note that the VDI protocol can be different for each client, depending on the VDI server in use (i.e., Citrix or VMWare) or depending upon the client itself (i.e., computer, thin client, or tablet). And the network infrastructure between each client and its VDI server may be substantially different. For example, one client may be remote, such as at a satellite medical facility that is connected by a T1 access line.

Conferencing between three or more endpoints will require the addition of a Multipoint Control Unit (MCU). Looking only at VDI Server 1 and VDI Server 2 conferencing paths, two additional paths would be added to the infrastructure for communication with the MCU. In this situation, the implementation may be made more complex if the protocol for each VDI server is different, such as when one of the clients is running a low bandwidth codec while another client is running a high bandwidth codec.

The quest for optimum performance and cost savings may further complicate the system. For example, if the organization is doing traffic engineering, asymmetric paths may result. Troubleshooting connectivity or performance problems in this type of environment can drive up the time and effort that it takes to diagnose problems.

The good news is that there are ways to tackle the complex task of diagnosing any potential problems. The bad news is that more advanced diagnostic tools will be needed to perform the troubleshooting within reasonable time frames. Simple packet capture tools can be used to look for specific symptoms, but the time required to perform the necessary analysis may make their use uneconomical.

Identify the Problem
You may learn that there is a multimedia problem because the people using the systems are reporting audio dropouts or jerky video. Proactive monitoring of the systems along the path can allow you to determine that there are problems, potentially heading off poor performance before it gets bad enough to have a big negative impact on the multimedia sessions.

When you are doing proactive systems monitoring, it is useful to configure the multimedia endpoints to report call stats to a central call controller for further analysis; the multimedia endpoints are the VDI Server 1 and VDI Server 2 (not the "Clients"). The ideal is getting RTCP info every 5 seconds, which allows you to determine how frequently the problem occurs. Without RTCP, obtain data about peak jitter and total packet loss from the server's multimedia-client application.

In the case of problems between each VDI client and its server, you'll need to monitor whatever performance measurement points are provided by the VDI software. It also makes sense to monitor network traffic statistics on both the VDI client and VDI server, looking for TCP retransmission counts and things like duplicate ACKs. A good network management product can help with basic network statistics monitoring.

Finally, the new generation of Application Performance Management (APM) products may be able to provide insight into a problem. These systems capture and analyze packet flows to identify application performance problems. They can typically measure jitter, packet loss, and server turnaround time to isolate the problem to the network, or to the server or the application.

Isolate the Path Components
Once you know that a problem exists, you can begin troubleshooting. You will need to isolate the source of the problem to one of the path components: 1) Client A to Server 1; 2) Server 1 to Server 2; or 3) Server 2 to Client B. Remember that the problem can be with the data flowing in one direction and not the other, so treat each direction separately for each path.

Once you think that you know the paths involved, check them thoroughly to confirm. I've seen a case where the video traffic was going to an MCU located on the Internet instead of to the corporate internal MCU. Traceroute between the two video systems took an entirely different internal path. The path via the Internet experienced a lot of jitter and loss while the internal path was clean. It took weeks of work before someone spotted the discrepancy in the configuration. Packet captures with a network analyzer or with an APM can verify that the endpoint addresses are correct. You may also need to look for network traffic engineering that may route the video traffic via a path that is different than what traceroute tells you.

The benefit of VDI is that all communications in the above scenario is routed through the data center. The installation of packet capture probes (e.g., Gigamon, Anue, etc) in the data center can significantly aid in the capture and analysis of multimedia and VDI flows.

Next Page: Troubleshooting Tips


Check out this recap of Enterprise Connect Orlando 2017, and register now to join us in 2018 and save $200 off or get a Free Expo Plus Pass.

Enterprise Connect Orlando 2018
March 12-15 | Orlando, FL

Connect with the Entire Enterprise Communications & Collaboration Ecosystem

Stay Up-to-Date: Hear industry visionaries in Keynotes and General Sessions delivering the latest insight on UC, mobility, collaboration and cloud

Grow Your Network: Connect with the largest gathering of enterprise IT and business leaders and influencers

Learn From Industry Leaders: Attend a full range of Conference Sessions, Free Programs and Special Events

Evaluate All Your Options: Engage with 190+ of the leading equipment, software and service providers

Have Fun! Mingle with sponsors, exhibitors, attendees, guest speakers and industry players during evening receptions

Register now with code NOJITTEREB to save $200 Off Advance Rates or get a FREE Expo Pass!

February 21, 2018

Business agility has become the strongest driver for enterprises to begin migrating their communications to the cloud-and its a benefit that enterprises are already realizing. To gain this benefit

February 7, 2018

Enterprises are starting to grasp the critical importance of security and compliance in their team collaboration deployments. And once the risks are mitigated, your enterprise can integrate these n

January 24, 2018

Communications, collaboration, and contact center systems are all being delivered from the cloud, to more enterprises each year. With the cloud growing in strategic importance, the question is what

February 16, 2018
What trends and technologies should you be up on for your contact center? Sheila McGee-Smith, Contact Center & Customer Experience track chair for Enterprise Connect 2018, gives us the lowdown.
February 9, 2018
Melanie Turek, VP of connected work research at Frost & Sullivan, walks us through key components -- and sticking points -- of customer-oriented digital transformation projects.
February 2, 2018
UC consultant Marty Parker has crunched lots of numbers evaluating UC options; tune in for what he's learned and tips for your own analysis.
January 26, 2018
Don't miss out on the fun! Organizer Alan Quayle shares details of his pre-Enterprise Connect hackathon, TADHack-mini '18, showcasing programmable communications.
December 20, 2017
Kevin Kieller, partner with enableUC, provides advice on how to move forward with your Skype for Business and Teams deployments.
December 20, 2017
Zeus Kerravala, principal analyst with ZK Research, shares his perspective on artificial intelligence and the future of team collaboration.
December 20, 2017
Delanda Coleman, Microsoft senior marketing manager, explains the Teams vision and shares use case examples.
November 30, 2017
With a ruling on the FCC's proposed order to dismantle the Open Internet Order expected this month, communications technology attorney Martha Buyer walks us through what's at stake.
October 23, 2017
Wondering which Office 365 collaboration tool to use when? Get quick pointers from CBT Nuggets instructor Simona Millham.
September 22, 2017
In this podcast, we explore the future of work with Robert Brown, AVP of the Cognizant Center for the Future of Work, who helps us answer the question, "What do we do when machines do everything?"
September 8, 2017
Greg Collins, a technology analyst and strategist with Exact Ventures, delivers a status report on 5G implementation plans and tells enterprises why they shouldn't wait to move ahead on potential use ....
August 25, 2017
Find out what business considerations are driving the SIP trunking market today, and learn a bit about how satisfied enterprises are with their providers. We talk with John Malone, president of The Ea....
August 16, 2017
World Vision U.S. is finding lots of goodness in RingCentral's cloud communications service, but as Randy Boyd, infrastructure architect at the global humanitarian nonprofit, tells us, he and his team....
August 11, 2017
Alicia Gee, director of unified communications at Sutter Physician Services, oversees the technical team supporting a 1,000-agent contact center running on Genesys PureConnect. She catches us up on th....
August 4, 2017
Andrew Prokop, communications evangelist with Arrow Systems Integration, has lately been working on integrating enterprise communications into Internet of Things ecosystems. He shares examples and off....
July 27, 2017
Industry watcher Elka Popova, a Frost & Sullivan program director, shares her perspective on this acquisition, discussing Mitel's market positioning, why the move makes sense, and more.
July 14, 2017
Lantre Barr, founder and CEO of Blacc Spot Media, urges any enterprise that's been on the fence about integrating real-time communications into business workflows to jump off and get started. Tune and....
June 28, 2017
Communications expert Tsahi Levent-Levi, author of the popular blog, keeps a running tally and comprehensive overview of communications platform-as-a-service offerings in his "Choosing a W....
June 9, 2017
If you think telecom expense management applies to nothing more than business phone lines, think again. Hyoun Park, founder and principal investigator with technology advisory Amalgam Insights, tells ....
June 2, 2017
Enterprises strategizing on mobility today, including for internal collaboration, don't have the luxury of learning as they go. Tony Rizzo, enterprise mobility specialist with Blue Hill Research, expl....
May 24, 2017
Mark Winther, head of IDC's global telecom consulting practice, gives us his take on how CPaaS providers evolve beyond the basic building blocks and address maturing enterprise needs.
May 18, 2017
Diane Myers, senior research director at IHS Markit, walks us through her 2017 UC-as-a-service report... and shares what might be to come in 2018.
April 28, 2017
Change isn't easy, but it is necessary. Tune in for advice and perspective from Zeus Kerravala, co-author of a "Digital Transformation for Dummies" special edition.
April 20, 2017
Robin Gareiss, president of Nemertes Research, shares insight gleaned from the firm's 12th annual UCC Total Cost of Operations study.
March 23, 2017
Tim Banting, of Current Analysis, gives us a peek into what the next three years will bring in advance of his Enterprise Connect session exploring the question: Will there be a new model for enterpris....
March 15, 2017
Andrew Prokop, communications evangelist with Arrow Systems Integration, discusses the evolving role of the all-important session border controller.
March 9, 2017
Organizer Alan Quayle gives us the lowdown on programmable communications and all you need to know about participating in this pre-Enterprise Connect hackathon.
March 3, 2017
From protecting against new vulnerabilities to keeping security assessments up to date, security consultant Mark Collier shares tips on how best to protect your UC systems.
February 24, 2017
UC analyst Blair Pleasant sorts through the myriad cloud architectural models underlying UCaaS and CCaaS offerings, and explains why knowing the differences matter.
February 17, 2017
From the most basics of basics to the hidden gotchas, UC consultant Melissa Swartz helps demystify the complex world of SIP trunking.
February 7, 2017
UC&C consultant Kevin Kieller, a partner at enableUC, shares pointers for making the right architectural choices for your Skype for Business deployment.
February 1, 2017
Elka Popova, a Frost & Sullivan program director, shares a status report on the UCaaS market today and offers her perspective on what large enterprises need before committing to UC in the cloud.
January 26, 2017
Andrew Davis, co-founder of Wainhouse Research and chair of the Video track at Enterprise Connect 2017, sorts through the myriad cloud video service options and shares how to tell if your choice is en....
January 23, 2017
Sheila McGee-Smith, Contact Center/Customer Experience track chair for Enterprise Connect 2017, tells us what we need to know about the role cloud software is playing in contact centers today.