Posts by fibrefool

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).

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...

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...

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:

https://www.ispreview.co.uk/review/top10.php

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...

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...

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).

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?

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...

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.

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.

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).