Eric Krapf
Eric Krapf is General Manager and Program Co-Chair for Enterprise Connect, the leading conference/exhibition and online events brand in the...
Read Full Bio >>

Eric Krapf | October 09, 2012 |


Video's Impact on the Network: An Update

Video's Impact on the Network: An Update Video can blow up your network, but with careful management and monitoring, it doesn't have to.

Video can blow up your network, but with careful management and monitoring, it doesn't have to.

The issue of video's impact on enterprise IP networks has been growing in importance and has been drawing ever-increasing crowds at Enterprise Connect sessions. So I wasn't entirely surprised that, when we put the subject on the program at last week's Interop New York, the room was pretty full at 9 AM on Friday morning. Terry Slattery of Chesapeake Netcraftsmen consultancy, who does this session for EC in Orlando, presented the Interop session as well, and here's a rundown on a few of the points he made:

* You have to be pretty granular in your understanding of what traffic is really "undesirable". Terry started off with a quiz: Is Skype video acceptable or unacceptable in an enterprise network? What about YouTube traffic? The answer, of course is: It depends. You need to understand your enterprise's policies and practices--are users given permission to use Skype for business? Does the HR department host training videos on YouTube?

Once you understand what you're allowed to block, you can monitor for this traffic, but you still have to be on the alert--"You won't often be told of new video deployments, so look at the network, understand what's going on there," Terry suggested.

Furthermore, even when you identify undesirable traffic, you can't afford to take a broad-brush approach to blocking it.

Terry described a case study in which a company was receiving complaints about application performance across a T3 link. Volume increased on weekday mornings and fell off around the time workers left the office. Analysis found that the applications were TCP/HTTP-based, and half of the traffic was coming from just three sources: Pandora, Akamai, and LimeLight Networks. In other words, a lot of non-business-related traffic. Right?

To a degree, yes. But Terry pointed out that blocking those three sources could have caused real problems: Akamai & LimeLight are content providers, but they don't just serve up nonessential entertainment content. In fact, Microsoft uses them to provide Windows software updates. So you can't just block them--you have to be more specific in blocking traffic types.

* Enterprises need to refine their buffering practices. Terry gave the example of a company that was experiencing dropped packets even after splitting traffic into two classes: Application for business-critical traffic, and Entertainment, for non-business-critical, which would get any leftover bandwidth that the Application queue didn't use.

But the enterprise wound up seeing two-thirds of its packet drops in the Application queue and just one-third in the Entertainment queue. What was going on? It turned out that the enterprise's buffers were the same size in both queues, so that the heavy Application traffic overwhelmed that queue's buffers, dropping packets, whereupon traffic switched over into the Entertainment queue. The solution was to increase the size of the buffers in the Application queue, which reduced drops here and used this bandwidth more efficiently.

One caveat that Terry gave: Don't make buffers too big, or TCP traffic will send retransmissions for packets that are still waiting in queue, since those packets won't have been acknowledged to the sending end during their retransmission window. This eats up bandwidth needlessly.

* Terry also offered up a case study of heavy bandwidth-usage impact on a wireless LAN deployment. Though the actual application in this instance was a data-based medical records app (not video), the application's behavior mimicked that of a big video download, Terry said. Hospital staff found that the app's 15MB patient data downloads slowed the WLAN to a crawl, with round-trip times ballooning from 10 milliseconds to 230 milliseconds--"That's like [the time it takes to go] around the earth and back," just to communicate with a datacenter in the same building, Terry said.

The incident was a reminder that wireless offers the unique challenge that, especially in older networks, the WLAN may back off to the lowest possible speed, and retransmissions may further slow the network down.

The solution was to rewrite the patient records application's download algorithm to transmit the big files incrementally, rather that in a single push.

The bottom line from Terry's session: Video can blow up your network, but with careful management and monitoring, it doesn't have to.


April 19, 2017

Now more than ever, enterprise contact centers have a unique opportunity to lead the way towards complete, digital transformation. Moving your contact center to the cloud is a starting point, quick

April 5, 2017

Its no secret that the cloud offers significant benefits to enterprises - including cost reduction, scalability, higher efficiency, and more flexibility. If your phone system and contact center are

March 22, 2017

As today's competitive business environments push workforces into overdrive, many enterprises are seeking ways of streamlining workflows while optimizing productivity, business agility, and speed.

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.