* Posts by fibrefool

26 posts • joined 23 Aug 2016

Looking for a great value broadband deal? War-torn Syria will do you proud


Virgin "FTTP"

You do know Virgin is HFC, not FTTP, right?

So fibre to a street cabinet and coax from there.

granted coax beats voice-grade twisted pair (hence their being able to offer faster speeds than OpenReach FTTC and with none of the "up to" malarkey).

Also cable has more upgrades to come. DAA (Distributed Access Architecture) moves the DOCSIS PHY from the head-end to the cabinet and so improves your SNR (so you'll get higher levels of QAM) while making node splits easier (so fewer users share the same bandwidth). And given a "Node+0" setup (no amplifiers between the cabinet and the home) you can do things like full-duplex and/or extended spectrum (both are part of DOCSIS 4.0).

We are absolutely, definitively, completely and utterly out of IPv4 addresses, warns RIPE


Re: Lies, damned lies, and statistics that don't lie.

"IIRC DECNet relied on - or assumed - that the MAC addresses were the subset allocated to DEC. Trying to get HP-UX boxes talking to a VAX with a VAX-oriented management we had to buy a DECNet package for HP-UX. When it was installed it promptly changed the MAC (which was programmable) to look like DEC. That confused all the clients until their caches caught up."

I think you'll find DECnet used locally-assigned MAC addresses rather than addresses "allocated" to DEC. So that's why the MAC changed on you once you fired up DECnet. The locally-assigned MACs encoded the DECnet station ID I think - so you didn't need an ARP equivalent.


cons of CONS

Sure - QoS is great with CONS.

But all the other stuff (scalability etc.) much less so. And any form of "per-call" billing (which connection-orientation tends to lead to) is a disaster.

iPhone price cuts are coming, teases Apple CEO. *Bring-bring* Hello, Apple UK? It's El Reg. You free to chat?


£832.50, not £999

There is this thing in the UK called VAT.

so iPhone prices in the UK are approx 10% higher than the US, not 30%. Can't imagine they'd do anything about that - since a further plunge in the pound could easily wipe out the difference.

and I can't see anything in the near future that could cause instability in the pound. Can you?

Ooh, my machine is SO much faster than yours... Oh, wait, that might be a bit of a problem...


Re: Silly NIC games ...

does anyone else remember Sun Microsystems and their Ethernet cards that were "aggressively compliant" with the CSMA/CD back-off spec?

meant that on any mixed LAN the Sun machines would out-perform everything else in terms of network I/O.

At 900k lines of code, ONOS is getting heavy. Can it go on a diet?


only 900k?

they're 3M LoC behind ODL:


and as usual it all comes down to how you define "SDN" :)

If most punters are unlikely to pay more for 5G, why all the rush?


Re: 5G Alternative to Wi-Fi

surely the stupidest 5G claim is the "remote surgery" one.

no way any remote surgeon gets to operate on me without fully redundant wired paths from surgeon to scalpel. And frankly I'd really rather those paths were called "left arm", and "right arm" (given an ambidextrous surgeon).

Tasty SYN-SYN-ACKs: Juniper gobbles HTBASE, ADTRAN's Oz NBN win and more



header compression?

(micro)flow-based forwarding?

in 2018?

or am I missing something?

Gigabit? More like, you can gigabet the US will fall behind on super-fast broadband access


Gigabit Internet costs

The main cost in providing FTTH is in running the last few metres of fibre into the home (i.e. digging a trench, putting a plastic tube in it, blowing fibre down the tube, and terminating the fibre in the home).


1) it's not about "Huawei kit" vs "US kit".

2) the cost is relative to local labour costs (so much cheaper to do this in China than in the US or UK).

3) the cost is relative to housing density (as that determines how many metres you have to dig).

4) fibre rollouts for FTTH and for mobile fronthaul are only loosely coupled (since those final few metres are required for the former but not the latter)

5) you need to find a way to depreciate the dig over a much longer term than the equipment (since passive assets are immune from Moore's Law)

Budget 2018: Landlords could be forced to grant access for full-fibre connections


Virgin Media and blocks of flats

I got Virgin into the block I used to live in (17 flats). We were redecorating/rewiring the communual areas so I persuaded them to give us the cable and we ran it into the new ducts ourselves. All they had to do was dig into our basement and stick a coax patch panel on the wall - so the cost per sub passed was pretty good.

But yeah - I had to push them to do it...

Form an orderly queue, people: 31,000 BT staff go to Openreach in October


Re: Adastral

of course fibre is cheaper than copper.

once you install it that is. it's all the digging that costs the money - not the chips...

IPv6 growth is slowing and no one knows why. Let's see if El Reg can address what's going on


Re: Internet task force takes IPv4 behind shed...

> I'm all ears for your suggestion.

Suggestion as to how to get to the "universal deployment of IPv6" (in the infamous words of the IETF "Scotch BoF")?

Well - it depends if you think that's a worthwhile goal ;)

To my mind IPv6 is a sad case of "second system syndrome". It will probably get there in the end (all those addresses come in very handy for IoT, container networking etc.) but it has all been so much more painful than it needed to be - but alas it's too late now to do something better.


Re: Internet task force takes IPv4 behind shed...

congratulations - I wondered how long it'd take for someone on the thread to suggest breaking IPv4 so IPv6 would get adopted ;)

Small UK firms laying fibre put BT's Openreach to shame – report



Project Lightning is still HFC, right? Not "full fibre".

Digital minister: We're still talking to BT about sorting crap broadband


Re: re: " just look at the success of LLU (local loop unbundling) for standard adsl."

"We've had both LLU and Sub-loop unbundling for years, yet a casual browse of SamKnows will show you that there have been very few takers, most ISPs simply went the BT Wholesale route..."

most ISPs yes. Most subscribers no:


you'll notice of the top 4 here one (BT itself) exclusively uses BT Wholesale. 1 (Virgin) uses its own infrastructure and the other two are LLU providers (I think they use BT Wholesale for exchanges where they don't have their own DSLAMs). Each of the top 4 is bigger than all the smaller ISPs combined.

with FTTC it's easier for the ISP to interconnect to Openreach (no DSLAMs needed any more). But of course true unbundling is harder - nobody's about to build out their own cabinets with VDSL or G.Fast DSLAMs in them. FTTP is that much harder of course - it's hard to imagine multiple operators digging to every home...

Networking vendors are good for free lunches, hopeless for networks


cheesy really is a clown...

...or at least needs to read up on recent developments.

the MSDC crowd have already ditched the IGP and run a pure eBGP environment for their leaf/spine fabrics. Once you have a dense, and regular, topology BGP turns out to be a better choice than an IGP. They've also turned summarisation off (doesn't work out so well if you put all the spines in the same AS but don't connect them to each other).

but for the SP WAN you really do need a link-state IGP (i.e. OSPF or ISIS). The topology is just too sparse and irregular, to do otherwise.

and in terms of "route learning via conversational characteristics" we already figured that out years ago with LISP.

at any rate the guy from EA sounds like he's parroting what the Stanford "SDN" guys were saying a few years back. Had they been right OpenFlow might have taken over the world. Looks like it didn't work out that way...

This many standards is dumb: Decoding 25Gb Ethernet and beyond


Re: Supply and demand

yes, I think this is all being driven by the cloud providers realising demanding 25Gbps.

something to do with switch chipsets being 25Gbps per lane. So 50G is actually cheaper than 40G (no need to rate-adapt between the switch chip and the PHY).

MNOs will lose 5G rewards to new entrants if they will not share networks


Not sure I agree with the article's conclusion that:

"The density of 5G in some areas will absolutely require sharing – a shared or neutral host approach will be the only one possible in locations where hundreds of cells are needed per square kilometre."

Surely sharing is key for rural areas where the cost of building out is high - and the goal is to get coverage (of e.g. 800Mhz 4G or 900Mhz 2G).

in denser areas as long as the reach of each individual cell-site is ok (depends on the frequency used) then there's no great need to share - as what you're after is capacity rather than coverage.

where sharing *might* be needed in dense 5G deployments is if the reach of Mmw radio is too short to enable each operator to build out enough cells.


Re: TLA not defined

yes - Radio Access Network. So the cell-site and its backhaul network towards the mobile core.

Don't rush into 5G until you've got a market, warns GTI chief


Re: 5G

I thought 4G was also more spectrally efficient than 2G or 3G, so while there's an overhead for VoIP you more than get that back from the higher bps/Hz?

YANG: Coming soon to a router near you


Re: Keep is standard, and simple

Not sure that YANG is fancy stuff that "creates vendor lock in". Rather it's the opposite - fancy stuff that makes it easier to manage boxes from multiple vendors (though sure, the nirvana of common data-models is still a ways off - especially given the IETF/OpenConfig fight).

and as for SNMP... well let's just say it's great for monitoring devices if you don't mind the devices' CPUs grinding to a halt as dozens of different management stations poll various overlapping sets of MIBs (the YANG crew intend to fix that using "YANG push") but it's piss-poor for configuration management (hence all those expect scripts that SPs use to manage their devices).

and yes, we've passed the 50 videos mark on YouTube for YANG. Just try searching for e.g. "NETCONF YANG" or "OpenDaylight Project" and you'll see what I mean...


Re: YANG loves YIN...

worth looking at OpenDaylight too as it's free and supports NETCONF/YANG southbound (as well as all the fancy "SDN" stuff like BGP-LS/PCE-P, OpenFlow, etc.), and both NETCONF/YANG and RESTCONF northbound. It also implements the OpenStack Neutron API so you can use it as the network provider in an OpenStack setup.

Swisscom claims world's first G.fast broadband service


4 pairs of Cat 6

it's not just that the copper is better - you also get 4 pairs to play with if you're doing 1000Base-T.

Ireland looks like it's outpacing Britain in the superfast broadband rollout stakes


apartment blocks

the issue comes down to the in-building wiring. It may be that the BT DPs are hung off the outside of the building, so dropping a fibre into the basement isn't much use. In other cases the BT lines may be internal but will be a voice grade pair to each flat rather than a 4-pair Cat-5E cable so you'd be looking at G.Fast rather than Ethernet for the final drop.

OpenFlow controller design killing SDN, say network boffins


SDN != Reactive OpenFlow

Agreed Rob. We've known that reactive flow control is a bad idea since long before SDN controllers were invented. Anyone remember Ipsilon Networks?

It's also worth remembering that SDN isn't just about OpenFlow (reactive or proactive). OpenDaylight, for example, also supports OF-Config, OVSDB, NETCONF/YANG, LISP, BGP, BMP, PCE-P, CAPWAP, OPFLEX, SXP, SNMP, USC (whatever that is), SNBI, HTTP, CoAP, LACP and PCMM/COPS. So expecting it to be the fastest reactive OpenFlow controller in the world is a bit like expecting your swiss army knife to be a better saw than your hacksaw. The real value in "SDN" (IMHO) is in writing apps that use multiple southbound protocols (e.g. learn topology from BGP-LS and program paths using PCE-P).


software switching

This isn't about software switching, it's about the control-plane. The article talks about line speed. But that's line speed relative to a server with 2 x 10GE ports. Nobody is suggesting using an SDN controller for the forwarding plane.

If you want to look at state of the art for general-purpose processor forwarding then take a look at FD.io. Though sure, I don't think anyone's suggesting replacing Ethernet switches with X86 servers with large numbers of 10GigE ports.


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