A/D and D/A: we're using an external RF front end that provides over 90 dB spurious free dynamic range. The poster who said these are big and hot was right; it's a little smaller than a PC case all by itself, with a hefty fan to dissipate the heat of the power amp. It covers 25 MHz worth of spectrum and costs a lot more than the HP server that does the signal processing.
Aye. Here's the rub. Big, hot, expensive, and the most critical piece of the puzzle. It's big, which is a problem for BST real-estate, often a very expensive part of the overall system. It's hot, which is a HUGE reliability problem in the real world (fans & thermal effects). It's expensive, because it's essentially a custom device with no commodity leverage. It's critical because the Vanu architecture digitizes & backhauls RF, which is a critical path function (note that this probably requires upwards of 400Mbps between antenna & controller... whew!!).
In other words, to make this type of system "carrier grade" and "highly available" (errrm... 6+ nines), this A/D-D/A subsystem will have to be at least doubly redundant on a per-base-station basis. So, instead of concentrating the high-value, high-sensitivity components at the core of the network, they're concentrated at the edge, which is counterintuitive at the very least. Without significant improvements in (a) speed, (b) reliability, (c) cost/form-factor, and (d) commodity leverage for the converter technology, this sort of system architecture is facing a very steep uphill battle. IMHO.
What kind of moron is running any version of Outlook?
Re:Break through technology.... or same thing ?
on
Roaming WLAN / GPRS
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· Score: 2, Interesting
yah, right. like mobile IP (v4) fixes everything.
how about triangle routing to the correspondent node... this will make big fun for anti-spoofing filters. you can always reverse tunnel, but what if your home agent is miles away and you're talking to somebody close by? and what about somebody spoofing your binding updates? and you can forget about dynamic handoffs. blag. i don't like MIPv4.
and good luck trying to use ipUnplugged stuff without their Roaming Server, or with home agent and mobile node behind different NAT devices, or trying to maintain advertised functionality without end-to-end ipU boxes.
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Ummm. This isn't "free" ... you paid for those minutes, and they're getting used faster while you waste your time with a 14.4 connection.
A/D and D/A: we're using an external RF front end that provides over 90 dB spurious free dynamic range. The poster who said these are big and hot was right; it's a little smaller than a PC case all by itself, with a hefty fan to dissipate the heat of the power amp. It covers 25 MHz worth of spectrum and costs a lot more than the HP server that does the signal processing.
Aye. Here's the rub. Big, hot, expensive, and the most critical piece of the puzzle. It's big, which is a problem for BST real-estate, often a very expensive part of the overall system. It's hot, which is a HUGE reliability problem in the real world (fans & thermal effects). It's expensive, because it's essentially a custom device with no commodity leverage. It's critical because the Vanu architecture digitizes & backhauls RF, which is a critical path function (note that this probably requires upwards of 400Mbps between antenna & controller ... whew!!).
In other words, to make this type of system "carrier grade" and "highly available" (errrm ... 6+ nines), this A/D-D/A subsystem will have to be at least doubly redundant on a per-base-station basis. So, instead of concentrating the high-value, high-sensitivity components at the core of the network, they're concentrated at the edge, which is counterintuitive at the very least. Without significant improvements in (a) speed, (b) reliability, (c) cost/form-factor, and (d) commodity leverage for the converter technology, this sort of system architecture is facing a very steep uphill battle. IMHO.
What kind of moron is running any version of Outlook?
how about triangle routing to the correspondent node ... this will make big fun for anti-spoofing filters. you can always reverse tunnel, but what if your home agent is miles away and you're talking to somebody close by? and what about somebody spoofing your binding updates? and you can forget about dynamic handoffs. blag. i don't like MIPv4.
and good luck trying to use ipUnplugged stuff without their Roaming Server, or with home agent and mobile node behind different NAT devices, or trying to maintain advertised functionality without end-to-end ipU boxes.
now, MIPv6 is another story entirely ... ;)