There’s this great debate in the IPv6 world about how to chop up your allocation into assignments for your customers. Typically, most ISPs are being handed a /32, and general guidelines say to allow for a /48 per DSL/leased line/cable customer.

However a lot of people are asking, why not a /64?  Quoted below is the sort of answer you’re likely to receive on NANOG, by one Mark Smith:

There are a variety of scenarios where customers, including residential, will benefit from having multiple subnets. They may wish to separate the wired and wireless segments, to prevent multicast IPTV from degrading wireless performance. They may wish to segregate the children/family PC from the adult PC network or SOHO network, allowing the subnet boundary to be an additional Internet access policy enforcement point. They’ll need separate subnets if they wish to use a different link layer technology, such as LoWPAN. They may wish to setup a separate subnet to act as a DMZ for Internet facing devices, such as a local web server for sharing photos with relatives. Game consoles may be put in a separate subnet to ensure file transfers don’t interfere with game traffic latency, using the subnet ID as a QoS classifier.

This answer is quite simply unrealistic. It’s the answer of a typical geek with no sense of perspective as to what the average consumer wants. It’s the opinion of what Mark Smith the network engineer and geek would want.

In the real world, most consumers of domestic internet services have absolutely no concept of IP addresses let alone subnetting, VLANs, segregation or quality of service. Most domestic networks are a single flat subnet with NAT to a single IP address and no servers that would require port forwarding, and rarely an IPTV system, but those are usually setup to use special triple-play routers configured by the ISP. Most domestic users just want to be able to plug stuff in and have it work.

Now, people will argue that there are more IPv6 addresses than there are atoms in the world. However that argument isn’t as good when you are assigning 1,208,925,819,614,629,500,000,000 IP addresses for just 2 or 3 devices. It’s a grossly inefficient waste no matter what you say. Not to mention that if you’re one of the big cable or DSL providers with millions of customers, it makes much more sense. Each barely used /48 that you throw out contains 256 /64′s.

As such, I personally am inclined to go for the default of a /64 per customer, but allow for a /48 should they need it. There is absolutely no point in issuing a /48 subnet to someone who is never ever going to use it… it’s just laziness, which is what got us into the current situation with IPv4 in the first place.

They tried to requote us for their 21CN broadband platform, assuming we take it in London as they wanted to charge us 50p per meter all the way from Manchester to Belfast (totaling some £250k). After carefully examining our current installation they decided that we should replace our pair of 34Mb pipes with a single pipe containing:

• 20 users on 24Mb ADSL sharing just 1Mb of bandwidth.
• All other users sharing 30Mb of bandwidth on old 20CN 8Mb ADSL.
• Added in enhanced care for all users at £8 a go.
• Forgot monthly broadband line rental charges at £7.90 a go.
• Will charge us for bandwidth across the 21CN network, plus charges for 3km of fibre across the London Docklands and we have to provide the BRAS – but yet they still have the balls to charge us £24k a year just for the privilege of doing business with the almighty BT Wholesale. Seriously, noone can explain what this charge is for given that they have separate charges for both bandwidth and fibre.

When I entered the correct figures into their shitty little price sheet, added in all the things they forgot, it came to a whopping £26 per user before any profit margin is added.

By comparison, Be/Fluidata is charging a non-recurring £3k to setup a simple crossconnect in any London Telehouse, and then all we pay are simple line charges depending on the product used, the average one of which is £16 per month.

It’s quite clear that BT Wholesale is not interested in providing any sort of service to other service providers. The ridiculous ordering/faults system, the outright denial of clear area-wide faults and now these ridiculous and quite arbitrary charges for access to their so-called 21st Century Network that still doesn’t properly support IPv6 are all very telling.

More numbers than you can shake a stick at. Just to give you an idea, at the ISP level (/32) that’s 79 septillion IP addresses assigned. That number is so big I had to go look it up on Wikipedia to find out what it’s called. Every home user will have 18 quntillion addresses at his disposal – I don’t have 18 quntillion pieces of lint  in my house, let alone a desire to connect every single one to the internet!

An issue that comes up for me at work time and time again is customers misunderstanding how bandwidth is measured.

Data is traditionally measured in Bytes. A CD contains 650MBytes of data. Bandwidth is measured in bits however, and this is what most customers misunderstand. A CD measured in terms of bandwidth, is 5,200Mbits (there are 8 bits per byte). Note that in writing, you use a capital ‘B’ to denote Bytes, and a lower-case ‘b’ to denote bits.

The issue is that bandwidth is traditionally measured in bits, not bytes. A 1Mbit circuit lets you download at 100KBytes/second. A lot of people make the mistake of thinking that a 1Mbit circuit is the same as downloading at 1MBytes/second.

This becomes a problem when a customer – as has happened today – complains of a slow speed problem. The systems (which I built and maintain) show this customer as downloading up to 32Gbits per day. They dispute this via the phone, proclaiming that they only downloaded “4 gig” (in a 5 hour window, I’ll add). If you do the math: 4*8 = 32. 32Gbits. On a standard ADSL line, that’s a crazy amount of usage – averaging around 1.8Mbit/s for that 5 hour window. During peak hours, an ADSL Max line (due to contention) may only be able to achieve 2Mb/s. It’s a classic case of someone mistaking Bytes for bits… of course, explaining that to them is another matter.