[SBE] Some IP Network questions

[Jonstv]

Ed et al-

Bo already talked about CDNs.  That's really the business model right now for public consumption.  However there are many services (or software as services) that can provide similar features for internal consumption.  (Wowza may be the largest back office software provide for this service.)  Where a (tv) business might need to view content for approvals, review or verification, IP can and does play a role.   For that type of content, you will often see MPEG4 content, low bit rate (3-5Mbps) transported across the network in a manner similar to how public consumption works.

So IPTV (Cat5 replacing Coax) operates similar to content distribution to the public.

But for high bit-rate / high bandwidth it is a /very/ different story.  Minimal hops, Jumbo Frames, 10Gb backbones are just the beginning.  What you have to remember though is that "bps" is "bps".  If you have an HD video signal uncompressed over an IP path, you need a 10Gb backbone to get one signal.  But you could get 6 signals on that one 10Gb path.

But it would be rare to move uncompressed video. At the very least JPEG2000 (J2K) would be used.

Video over IP (live video) is a high bit rate / high bandwidth product.  Minimal buffering is required to maintain a steady stream (which means larger packets which means Jumbo Frames). Compared to audio, which has much fewer bits per sample, video over IP needs to be properly managed.  Google TVIPS.

However, video /file/ transfer is different than Video over IP.  It does not need to be real time.  Achieving real time or better is an advantage but may not be required.  

Whatever type of "data" you are moving, you don't want to saturate the "pipe" at the narrowest point.  If you have a 10Gb backbone, but you external access is DSL, you're not going to be able to move any content out of the building.

And again, it's just math.  If your audio signal is 100kbps, that's about the bandwidth you need.

As for QoS, they most desirable way to handle non-computer IP traffic is on a dedicated network.  At my facility, we have a dedicated network(s) that handle our "broadcast" network traffic. Internet, email, etc is handled on a different network.  This insures the best service possible for each application.  No QoS is required because each service is just as important, and there is no "unimportant" traffic being based.

I do hope this makes some sense.  It's been a long few days so... ;)

Jonathan
CBT,CBNT
Sent from my iPad

On Jun 19, 2011, at 2:27 PM, Edwin Bukont <ebukont at msn.com> wrote:


> For both the video and audio folks, questions.

>  

> 1.  A friend, who is usually knowledgeable, made the statement that CNN generates many IP streams, reliably, for public consumption and that my concerns about network infrastructure  (Physical and Layers 1,2 and maybe 3) are overblown.  He claims that the technology has come so far that as long as you buy Cisco, HP, Juniper and focus on proper configuration (Layers 4-7), you can reliably do what you want.  He claims that network issues rarely are at the lower levels and mostly now occur as a function of poor config and management, not poor infrastructure.    My comment to him was that how you handle IP / IPTV for post-production streams is a completely different animal than how you handle IP connectivity concerns inside the plant related to bi-directional workflow for production.   I would tend to think that the integrity of the lower levels matters more for production than for distribution.

>  

>  So I am curious, what is CNN doing and how does their use of IP technology, complexity and network reliability concerns differ between production and distribution?  Is CNN (as my Cisco buddy claims) more concerned now with distribution rather than production because so much production now is ingested from citizen journalism?  I don't believe that the brick and mortar concerns of TV plants have really dimished that far, yet.

>  

> 2.  Anyone tried use of 802.1(Qav et al) enabled switches yet in AOIP or IPTV plants.  Such switches do exist already.  Are there broadcast production devices encorporating these standards?  Anyone have experience at how well these switches handle L3 QoS for packets not bearing AVB?

>  

> 3.  Anyone using a wireless packet sniffer?  If so, what, besides Fluke, are folks using?

>  

> Thanks

>  

> 

> 

> Edwin Bukont CSRE, DRB, CBNT 

> E2 Technical Services LLC

> Tech-Knowledgy for Signal Integrity

> Nashville, Baltimore, Whereever

> V- 240.417.2475; F- 240.368.1265

> 

>  

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