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Comment Re:Why Better than Parachute? (Score 3, Insightful) 206

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.

Comment Re: Record is over a petabit per second (Score 1) 57

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."

Comment Re: So much slower than 100GBase-RZ...? (Score 3, Informative) 57

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.

Comment Re:Practical question for consumers (Score 1) 294

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 /16 (2 bytes) boundaries. It allocates based on whatever is appropriate. The latest allocation was a /12 to ARIN. I don't see that it has ever allocated a /16 either. (a /16 was reserved for 6to4) http://www.iana.org/assignment...

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 /48s which would fit into a /24 quite nicely.

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 /48, as you mentioned, would give each customer 16 bits of subnetting address, so you now have a deficit of 5. Which is why RIRs like APNIC and RIPE assign /56s instead. Each customer that way gets 8 bits of subnetting, instead of 16. Which may or may not be adequate.

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...

Comment Re:Practical question for consumers (Score 1) 294

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 /32, and you had better be a huuuuugge organization - maybe global - w/ millions of SUBNETS to justify that. So now the ISP has 48 bits, down from the 64 - 2001:db8:b10c:abcd::/64.

...

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 /48, as you mentioned, would give each customer 16 bits of subnetting address, so you now have a deficit of 5. Which is why RIRs like APNIC and RIPE assign /56s instead. Each customer that way gets 8 bits of subnetting, instead of 16. Which may or may not be adequate.

A lot of this is incorrect. RIPE by default allocate a /29 to ISPs. Getting something larger than that is super easy, as long as you have the documentation to back it up.

Also RIRs don't assign /56s to customers. The RIR allocates a prefix to a LIR (Your ISP) and the LIR allocates the addresses down to the customer.

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 /48 for end user allocation. (https://www.ripe.net/publications/docs/ripe-655. If you read from section 5.3 onwards you will see that it is up to the ISP to decide what to allocate to a customer. Anything shorter than a /48 requires documentation, but a /48 is just fine if you want. The wording has actually changed on that page recently. It used to be more specific about recommendation of prefix sizes.

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 /48's available. Even with outlandish allocation policies it is unlikely to ever run out. At least not in the useful life of the protocol. We are bound to hit some limitations with IPv6, but it was designed to not be the size of the address space. Why stifle potential innovation?

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.

Comment Re:Practical question for consumers (Score 2) 294

Not giving everyone a /48 is a daft argument. From someone who is a lot smarter than me source

"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 /48s which would require a /24. Let’s give each of those an additional 8 bits for overhead and bad splits and say each of them gets a /16. That’s 2,800 out of
65,536 /16s and we’ve served every customer on the planet with a lot of extra overhead, using approximately 4% of the address space.

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 /28 (100,000 /48s doesn’t fit in a /32, so we bump them up to /28). Adding in bad splits and overhead at a nibble each, we give each of them a /20. 140,000 /20s out of 1,048,576 total of which we used 44,800 for the MEGA ISPS leaves us with 863,776 /20s still available. We’ve now managed to burn approximately 18% of the total address space and we’ve served the entire world twice.

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 /32. Backing that off two nibbles for bad splits and overhead, we give each one a /24.

This will require 2,800,000 /24s. (I realize lots of ISPs server fewer than 5,000 customers, but those ISPs also don’t serve a total of 14 billion end sites,
so I think in terms of averages, this is not an unreasonable place to throw the dart).

There are 16,777,216 /24s in total, but we’ve already used 2,956,800 for the MEGA and LARGE ISPs, bringing our total utilization to 5,756,800 /24s.

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."

Comment Re:Many happy returns, IPv6 (Score 2) 294

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.

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