Comment Re:Why Better than Parachute? (Score 1) 206
I meant bringing them back with parachutes. A burn back is much more controlled.
I meant bringing them back with parachutes. A burn back is much more controlled.
The damage is caused by the salt in the water. Missed that out!
Ditching it in the sea and recovering it causes too much damage to make it viable to refit. This was intended for the boosters on the space shuttle, but it ended up being cheaper to make new ones than fix the old ones.
Of course they could bring them down over land, but I think the unpredictability of exactly where they would land could be marginally terrifying.
Yes, QPSK does send 2 symbols, but DP-QPSK doubles that to 4 symbols.
Multiple cores, multiple fibres. Effectively the same thing. I believe this test was over 1 core. That's the big difference.
That was using multiple wavelengths on multiple fibres. This appears to be one wavelength on one fibre. Different kettle of fish.
"Researchers from the NEC Labs in Princeton, NJ, USA, and from Corningâ(TM)s Sullivan Park Research Center in Corning, NY, successfully demonstrated ultra-high speed transmission with a capacity of 1.05 petabit/s (1015 bits per second) over novel multi-core fiber that contains 12 single-mode and two few-mode cores by employing the advanced space division multiplexing scheme and optical multiple-input multiple-output signal processing technique."
Nope, that is 100Gbase-(L/S/E)R4. ZR uses DP-QSPK.
"The superchannel is an advanced dense wave division multiplexing (DWDM) technique, created by combining multiple coherent optical signals into one channel"
Not quite. Those optics use DP-QPSK, which uses mathematical magic to cram 4 bits worth of information into one symbol. This means the optics only need to operate at 25Gbps to supply a 100Gbps line rate.
DP-QPSK is a whole load of magic I don't understand.
If DP-QPSK can be used with this technology, it seems to imply 200Gbps optics are not too far away.
Google will fix this by updating the ASOP with their fix in the latest version. Possibly even a few previous versions too.
The problem is the handset makers and carriers won't push the updates down to the handsets they support.
So now, you have just the global prefix space. Of this, the first 2 bytes are assigned by the IANA to the RIR - the 2001, the 2400.... It's not a part of what your RIR gets to give you.
I've been trying to work out what you mean by all this.
IANA doesn't allocate to RIRs on
Now, depending on the geographic reach of the ISP, they may need thousands of offices nationwide, and in each office, service several thousands of people. Let us assume that we have 16 million routers serviced that way - that is 2^14. So your 32 bits are now down to 18. So it now comes down to how many people are serviced by a single central office router. Lets assume it's 128, which is 2^7, and you are down to 11.
This really doesn't make sense to me. Firstly 2^14 is around 16k, not 16 million... What are these routers that you are servicing? CPEs? In this scenario you require 16 million
So you are already cutting into the subnet address space of the IPv6 address, since you have only 11 bits to give a customer for subnetting. Giving everyone a
I genuinely don't understand what you are talking about. Maybe a diagram would help? You mention an inherent structure in v6 addresses. Maybe that is where you are getting confused, because other than the 64:64 split, there is none as such...
So now, you have just the global prefix space. Of this, the first 2 bytes are assigned by the IANA to the RIR - the 2001, the 2400.... It's not a part of what your RIR gets to give you. The best your RIR can give you is a
So you are already cutting into the subnet address space of the IPv6 address, since you have only 11 bits to give a customer for subnetting. Giving everyone a
A lot of this is incorrect. RIPE by default allocate a
Also RIRs don't assign
And finally the RIPE policy (and likely others. I live and work in the RIPE region so my knowledge is more relevant to that region) recommends a
There is nothing inherently special about any of the top 64 bits. While they are divvied out to RIRs by reserving so many bits from the top, it doesn't break the maths that there is a fuck tonne of
And splitting the address space any other way was never an option. It was always going to be 64 bits at the top, and there was only ever a question about the size of the bottom part of the address.
Maybe that was the case on some super old Cisco kit. Anything bought in the past 5 years at least has forwarding in hardware for all packets.
Not giving everyone a
"Let’s assume that ISPs come in essentially 3 flavors. MEGA (The Verizons, AT&Ts, Comcasts, etc. of the world) having more than 5 million customers, LARGE (having between 100,000and 5 million customers) and SMALL (having fewer than 100,000 customers).
Let’s assume the worst possible splits and add 1 nibble to the minimum needed for each ISP and another nibble for overhead.
Further, let’s assume that 7 billion people on earth all live in individual households and that each of them runs their own small business bringing the total customer base worldwide to 14 billion.
If everyone subscribes to a MEGA and each MEGA serves 5 million customers, we need 2,800 MEGA ISPs. Each of those will need 5,000,000
65,536
Now, let’s make another copy of earth and serve everyone on a LARGE ISP with only 100,000 customers each. This requires 140,000 LARGE ISPs each of whom will need a
Finally, let us serve every customer in the world using a small ISP. Let’s assume that each small ISP only serves about 5,000 customers. For 5,000 customers, we would need a
This will require 2,800,000
so I think in terms of averages, this is not an unreasonable place to throw the dart).
There are 16,777,216
We have now built three complete copies of the internet with some really huge assumptions about number of households and businesses added in and we still have only used roughly 34% of the total address space, including nibble boundary round-ups and everything else."
Is that the metric that keeps IPv6 adaption capped?
I asked the owner of an ISP how he was going to deal with IPv6. His answer was, "Buy a lot of expensive hardware." That is the metric that keeps IPv6 adoption capped: people don't want to pay for new hardware.
As someone who works for ISPs for a living, that is nonsense. Equipment generally has a lifetime that it is useful for. We typically buy kit with 5 years in mind, but may stretch it further if there is still life in it. Equipment that is 10 years old is probably worthless (This likely is the same for most other areas of IT)
Any equipment you buy today will support IPv6, with all the latest standards. Equipment generally gets firmware upgrades for the duration of its life that adds new features as they come along.
All Cisco and Juniper kit (2 big vendors in the ISP space) have had full feature sets for v6 in the service provider routed world for quite some time now. So long that some of their kit has gone end of life that have v6 support. There may be some enterprise grade products where this doesn't hold true, but it shouldn't be far off.
If your friend claims that the way he is going to deal with v6 is to buy more kit, he is either running outdated equipment, stupid, or lying.
The CPE is the only major space where there is issues. This is getting better now, and the same 5 year rule generally applies here to ageing equipment. You have the luxury of a phased replacement plan in this space too, which makes things a bit simpler.
Top Ten Things Overheard At The ANSI C Draft Committee Meetings: (6) Them bats is smart; they use radar.