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Author Topic: Blackbox Switches for Cobranet (was: equipment mounted in ceiling spaces)  (Read 7393 times)

Greg Bellotte

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Re: Blackbox brand switches for Cobranet
« Reply #30 on: August 25, 2007, 11:47:41 am »

Jason Lavoie wrote on Sat, 28 July 2007 18:11

... or does a bundle take up the same amount of network traffic even if it's not full?

Jason


for the most part, a bundle takes the same bandwidth regardless of its content. a bundle with one channel of audio still contains seven channels of silence, repesented by a boatload of digital zeroes.

as for maximum bundles to transmit, i have successfully set up a system with nine broadcast (multicast) bundles for a total of 72 channels of audio (actually we had two parallel systems for 144!). everything was moving in one direction, and we had three sets of units to receive in three different locations. this seems to be about the limit for multicast, as the bandwidth of our 100mbit switch was pretty much at its limit. gigabit switches DO NOT help, as the 100 mbit ports on the cobranet units will still get clogged with multicast traffic.

as for cat5 length, 100m *IS* the number, and existed long before cobranet. longer runs require a repeater, switch, or media converter/fiber extension. the above system was originally on <100m cat5 and worked very reliably. we set up this same system again, with 100mbit fiber links between the sending and receiving units about 3000ft apart. we found we lost enough bandwidth through the media converters to limit us to eight broadcast bundles. still a lot of signals.

as noted before, you should really limit the use of multicast bundles when possible. the switch is required to pass these packets to all rx units, even if they wont be needing them. a unicast bundle will only be passed to the unit that needs it, so you can have many more bundles than 9 if you plan it out right.

Josh Millward

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Re: Blackbox brand switches for Cobranet
« Reply #31 on: August 26, 2007, 01:16:06 am »

Jason Lavoie wrote on Sat, 28 July 2007 18:11

... or does a bundle take up the same amount of network traffic even if it's not full?Jason


This really depends on how you set up your bundles. Like Greg said above, if you set the bundle up as an 8 channel bundle, then use only 2 channels on it, you will still use up a full 8 channel bundle's bandwidth, since you are still transmitting 6 empty channels. However, if you set up that bundle as a 2 channel bundle, it will take up less network bandwidth since the bundle is smaller.

Of course, this depends on having the ability to set up advanced Cobranet mapping. Many devices can not do this. Some can. Actually, if you use the latest version of Disco, you can do advanced mapping with any Cobranet device. However, this is fairly advanced and the manufacturer of the products you are using may not support you in doing this. There are some fun settings to get worked out to enable it to not forget these settings on a reboot and to modify the settings you HAVE to use Disco since you are bypassing the manufacturer's setup.

Greg Bellotte wrote on Sat, 25 August 2007 11:47

as for maximum bundles to transmit, i have successfully set up a system with nine broadcast (multicast) bundles for a total of 72 channels of audio (actually we had two parallel systems for 144!). everything was moving in one direction, and we had three sets of units to receive in three different locations. this seems to be about the limit for multicast, as the bandwidth of our 100mbit switch was pretty much at its limit. gigabit switches DO NOT help, as the 100 mbit ports on the cobranet units will still get clogged with multicast traffic.


Greg, I am stunned that system worked. You must have had some serious network hardware and no other network traffic. I mean, that is just a LOT of network traffic since they are all multicasting! Wow. Very cool. This is awesome information to know! Thanks for sharing!

-Josh
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Josh Millward
Danley Sound Labs

Ron Hebbard

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Re: Blackbox brand switches for Cobranet
« Reply #32 on: August 26, 2007, 06:05:07 am »

Greg Bellotte wrote on Sat, 25 August 2007 16:47

Jason Lavoie wrote on Sat, 28 July 2007 18:11

... or does a bundle take up the same amount of network traffic even if it's not full?

Jason


for the most part, a bundle takes the same bandwidth regardless of its content. a bundle with one channel of audio still contains seven channels of silence, repesented by a boatload of digital zeroes.

as for maximum bundles to transmit, i have successfully set up a system with nine broadcast (multicast) bundles for a total of 72 channels of audio (actually we had two parallel systems for 144!). everything was moving in one direction, and we had three sets of units to receive in three different locations. this seems to be about the limit for multicast, as the bandwidth of our 100mbit switch was pretty much at its limit. gigabit switches DO NOT help, as the 100 mbit ports on the cobranet units will still get clogged with multicast traffic.

as for cat5 length, 100m *IS* the number, and existed long before cobranet. longer runs require a repeater, switch, or media converter/fiber extension. the above system was originally on <100m cat5 and worked very reliably. we set up this same system again, with 100mbit fiber links between the sending and receiving units about 3000ft apart. we found we lost enough bandwidth through the media converters to limit us to eight broadcast bundles. still a lot of signals.

as noted before, you should really limit the use of multicast bundles when possible. the switch is required to pass these packets to all rx units, even if they wont be needing them. a unicast bundle will only be passed to the unit that needs it, so you can have many more bundles than 9 if you plan it out right.



Hello Greg;

May I ask what you were using this for?

Toodleoo!
Ron Hebbard
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Karl P(eterson)

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Re: Blackbox brand switches for Cobranet
« Reply #33 on: August 26, 2007, 10:53:42 am »

Jason Lavoie wrote on Sun, 05 August 2007 17:24


I'm confused though because we're still moving the same quantity of data, just encoding and decoding faster right?
maybe I'm missing something here..


It would seem like that would be the case, doesn't it? - Unfortunately though, it isn't. By lowering the latency, you are actually sending the data more frequently, hence increasing the data transfer traffic flow, thus a higher network saturation.

Help?

Karl P
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Karl P(eterson)

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Re: Blackbox brand switches for Cobranet
« Reply #34 on: August 26, 2007, 11:31:01 am »

Greg Bellotte wrote on Sat, 25 August 2007 11:47

we set up this same system again, with 100mbit fiber links between the sending and receiving units about 3000ft apart. we found we lost enough bandwidth through the media converters to limit us to eight broadcast bundles. still a lot of signals.


In order to have gotten that much signal on the net in the first place, I will assume that  you needed to use pro level switching (HP, Cisco) to start with. If that is the case, you should have used gigabit fiber cards in the switches and this would have given you enough inter-switch bandwidth to tolerate the loss from the conversion process. Since you would be using internal switch cards on both sides, the latency in the line itself would have been much more conducive to (safely) running the system on the limits of its capabilities than with media converters.

Karl P
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Greg Bellotte

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Re: Blackbox brand switches for Cobranet
« Reply #35 on: August 26, 2007, 02:57:10 pm »

@josh-we always setup cobranet on it's own physical network, with *NO* other traffic. in this case we actually had two networks, one for each half of the system. wish i could say we had some serious switch hardware, but the equipment vendor thought since the cobranet boxes had two rj-45 ports that they could all be daisy chained. we bought a bunch of 8 port switches at office depot ($29 each!) to get us through show #1. still using them... Surprised

@ron-the system mentioned was audio distribution for network television coverage of several major golf events. the origination of signals and the first receive point was for the domestic coverage, the secondary receive points were international broadcast units.

@karl-as mentioned above, no, we are not using pro level switching hardware of any kind so we don't have any internal uplinking ports. I do think that gigibit fiber would have helped. once again, the equipment vendor kind of killed us. they sent evertz wdm media converters, but sent units of the same kind-not ones with reciprocal tx/rx so nothing talked to each other. i ended up using some of my own MC's that i usually just use to grab some internet. apparently they are of the "store and forward" design and the latency was just enough to kill the ninth bundle. curiously, it's the last bundle to check in that gets hammered. the problem wasn't terrible, but audio at this level must be perfect.

my future specs will call for managed switches and gigibit fiber links. we can then split the switches into vlans and use one physical cat5 system for even more channels than we use now. i'm shooting for 256 channels on a single fiber run!

Karl P(eterson)

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Re: Blackbox brand switches for Cobranet
« Reply #36 on: August 26, 2007, 07:43:09 pm »

Greg Bellotte wrote on Sun, 26 August 2007 14:57


my future specs will call for managed switches and gigibit fiber links. we can then split the switches into vlans and use one physical cat5 system for even more channels than we use now. i'm shooting for 256 channels on a single fiber run!


With proper use of VLAN's and trunking architecture, the sky is (almost) the limit. It would not be crazy to assume that you could get 640 channels on a single fiber run with proper VLAN isolation techniques. Of course, assuming that the hardware cooperated and the layout was conducive, you could theoretically have 13 thousand channels running on a system comprised of a core 10Gigabit ring network with smart VLANS and real time in-switch routing.

Karl P
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