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TV a partir de uma rede

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would reach its capacity and<br />

it‘s especially the connection<br />

from the server to the switch<br />

that would need to withstand<br />

enormous amounts of data.<br />

The question often arises<br />

if IP<strong>TV</strong> should be operated<br />

at 100MBPS or would it be<br />

better at 1000MBPS (also<br />

referred to as 1GBPS or<br />

1GBit/s). It‘s not an easy<br />

answer; it <strong>de</strong>pends ultimately<br />

on how you want to<br />

use IP<strong>TV</strong> and the network.<br />

158 TELE-audiovision International — The World‘s Largest Digital <strong>TV</strong> Tra<strong>de</strong> Magazine — 09-10/2013 — www.TELE-audiovision.com<br />

8 9<br />

10<br />

11<br />

When different receivers will<br />

only route single transpon<strong>de</strong>rs<br />

to one or more multiplexers,<br />

then for the most part<br />

a 100MBPS network would<br />

suffice. Quite often professional<br />

receivers only oper-<br />

8. Despite having a perfect<br />

picture, StreamXpert indicates<br />

some errors in PAT and PMT.<br />

Interestingly; these were<br />

already present in the original<br />

DVB-S stream…<br />

9. Useful information provi<strong>de</strong>d<br />

by StreamXpert: the grid<br />

view, where all active services<br />

within the stream are mapped<br />

according to their PID.<br />

10. Meanwhile, we monitor<br />

our Dexing NDS3975 with<br />

the SnmpNMS management<br />

software. This application<br />

gives us remote access to the<br />

internals of this integrated<br />

professional receiver.<br />

11. On the Mux-tab, we can<br />

specify which channels of<br />

the three different incoming<br />

transpon<strong>de</strong>rs (through the<br />

internal tuner, ASI-in and IP<strong>TV</strong>)<br />

we want to output.<br />

ate via a 100MBPS interface;<br />

in view of the fact that the<br />

bandwidth of common DVB-<br />

S/S2 transpon<strong>de</strong>rs transport<br />

data on average at 50MBPS,<br />

this would be sufficient.<br />

All the IP<strong>TV</strong> receivers we<br />

know of also operate on a<br />

100MBPS network interface.<br />

Why then would you want to<br />

upgra<strong>de</strong> to a 1000MBPS infrastructure?<br />

The simplest<br />

explanation is this: if cars<br />

could only drive at 55 MPH,<br />

then in principle single-lane<br />

roads would be good enough.<br />

But if there are a large number<br />

of cars all on the road at<br />

the same time, then a multilane<br />

highway would be much<br />

better even though the cars<br />

would be moving no faster<br />

than 55 MPH. A 100MBPS<br />

switch is <strong>de</strong>signed for this<br />

speed and would fall to its<br />

knees if all the ports would<br />

sud<strong>de</strong>nly <strong>de</strong>mand high data<br />

transfer rates at the same<br />

time. A 1000MBPS switch is

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