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Challenges in Deploying IP Video based Applications – Part 3: Quality

November 24, 2010 at 8:27 am PST

Higher quality in video is obtained by using higher resolutions, more colors (increased bits per pixel), spatial audio (multiple audio channels and higher sampling rates), and multiple displays. All of these parameters increase demand for bandwidth — in turn increasing the sensitivity to degraded network conditions.

With video, when the impairments become apparent, the experience of the session deteriorates very quickly. Users are easily disturbed by poor video quality — and the bandwidth burden of video means that even slight deterioration of services within the network can significantly affect the video experience. Similarly, with video, the accompanying audio experience must be satisfactory and synchronization with the video must be consistent — and even more stringent requirement.

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Challenges in Deploying IP Video based Applications – Part 2: Performance

November 23, 2010 at 8:17 am PST

Video applications can be very sensitive to aspects of network performance. After the video has been packetized for IP transport, the network’s contribution to the video stream’s performance is generally limited to delay, jitter, and loss.

Delays arise from physical limits (speed of light) as well as queuing mechanisms in routers and gateways that the packets traverse along the way. When delay increases above 400 milliseconds (camera to display), people become aware of it and the delay starts to impede interactive communications.

Jitter is the variability of delay. Buffers can be used to smooth out variations in delay. However, too much buffering adds delay and prevents effective interactive video.

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Smart Access to Borderless Networks

I guess it’s a bit natural to feel a sense of pride when you are a part of the team that has innovated the vast majority of LAN Access switch features in the market. I joined this group about 2 years ago and have been in awe ever since. If innovation and the sheer brilliance of simplicity excites you then this should be a fun read.

It is probably obvious that every single endpoint connects to the network ONLY through an access switch. Even the wireless ones.. through the access point that is plugged into the access switch. So no endpoint can get into the network without going through an access switch.

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Challenges in Deploying IP Video based Applications – Part 1: Introduction and Predictability

November 19, 2010 at 9:27 am PST

The deployment of network video applications presents several challenges for the network and application administrator. These challenges can be categorized into having predictability, offering performance, and delivering quality.

The deployment and integration of voice into the network was relatively simple compared to the challenges being brought by multi-faceted IP video applications. As with Voice over IP (VoIP), video over IP allows the reuse and convergence of communications infrastructure. Where different types of delivery mechanisms (satellite, DVDs, taps, and coax) were needed for the various types of video, a single transport system can now be used. With VoIP, there was concern regarding some aspects of network characteristics such as delay and jitter. If the video application is an interactive one like video conferencing, then delay and jitter do remain important. However, in other types of video applications (for example video surveillance), the amount of raw bandwidth to deliver high quality video can also be a limiting factor. Additionally, unlike voice, minute network degradations can result in easily noticeable impairments that remain on screen for a longer amount of time.

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All Applications and No Performance makes Work a Dull Boy: Part 2

In my earlier blog, I introduced the concept of Application Velocity and how Cisco is addressing the application performance issue as a holistic approach under Borderless Networks Architecture. I touched upon one of the key components – Visibility – under this concept and the need for it.

Let’s focus on the other two components under Application Velocity starting with Optimization…

Optimization: The second component to Application Velocity addresses the traditional role of application and network optimization. This includes compression, caching and protocol optimizations like Wide Area Application Services (WAAS) as well as quality of service (QoS) based controls to deliver speedier responses to endpoints.

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