optical network

[radix]

My own optical modem is actively filtering out tens or hundreds of gigabytes per second of other users' data right now on this single fiber coming to my home, and yet I still get steady 4ms ping to Cloudflare's DNS server even on Wi-Fi. So why would network cables even matter at all once it works?

There are specialized situations, like the inside of a factory or at a high-density exchange. The far-end noise from a zillion copper cables at an exchange is what limits the upload capacity of copper. That's why ADSL worked, there was very little noise at the home, so one could decode a low power signal, but there's too much interference at the exchange for a good uplink. Several companies made FDM-like DSL boxes that optimized the frequency usage of each pair to minimize interference, but in the end coax or fiber is the only way to get reliable and high-speed bi-directional links in those situations.

Within a home, it does not matter at all. Maybe if you wanted to have that 400' run over your 3 acre property, optical would be a good idea just for the distance.

 

[voodooless]

My own optical modem is actively filtering out tens or hundreds of gigabytes per second of other users' data right now on this single fiber coming to my home

No, it’s not. You only get your data through that fiber, not that of other users.

 

[Palladium]

No, it’s not. You only get your data through that fiber, not that of other users.

Please read up on a passive optical network, at least I know mine does and I worked on it.

 

[voodooless]

Please read up on a passive optical network, at least I know mine does and I worked on it.

Thanks, I wasn’t aware of this madness The filtering though doesn’t seem like a lot of trouble, a simple SFP+ module, and it’s MAC does all the “heavy” work.

 

[antcollinet]

Thanks, I wasn’t aware of this madness The filtering though doesn’t seem like a lot of trouble, a simple SFP+ module, and it’s MAC does all the “heavy” work.

I too would have assumed that the filtering is done upstream somewhere, before the subscribers fibre.

EDIT : And I've just learned that passive is what BT are offering in the UK - But the network is currently based on 2.5Gb/s trunk lines, certainly not 10's or 100's (and that is Gbit /s, not Gbyte /s)

A trunk line is shared by a maximum of 32 users.

 

[audio_tony]

It's reminiscent of old network hub technology where the traffic appeared on every network port.

Ah the joys of broadcast storms etc...

P.S. I realise the technology is somewhat different...

 

[bloodshoteyed]

It's reminiscent of old network hub technology where the traffic appeared on every network port.

if you're thinking of ring topology, it' out of use basicaly anywhere for at least 20 years now...
haven't seen coax networks in use for about 25 years now and the last remnants of IBM's token ring we've thrown out 20+ years ago at my last workplace (and we were CHEAP, holding onto ancient stuff)

 

[antcollinet]

if you're thinking of ring topology, it' out of use basicaly anywhere for at least 20 years now...
haven't seen coax networks in use for about 25 years now and the last remnants of IBM's token ring we've thrown out 20+ years ago at my last workplace (and we were CHEAP, holding onto ancient stuff)

I think he was referring to ethernet, but hub connected rather than switch connected. Where switches actually deliver packets to the correct device, hubs just connected everything to everything else. All the cables carried all the network traffic.

 

[JayGilb]

Please read up on a passive optical network, at least I know mine does and I worked on it.

From Wikipedia passive optical network.

 

[audio_tony]

I think he was referring to ethernet, but hub connected rather than switch connected. Where switches actually deliver packets to the correct device, hubs just connected everything to everything else. All the cables carried all the network traffic.

Precisely what I was referring to, thank you!

I'm not old enough to have worked with the other stuff (AUI I think?) Might be token ring.

 

[radix]

I'm not old enough to have worked with the other stuff (AUI I think?) Might be token ring.

An AUI (formally called a DIX) is an intermediate media-independent interface. One could plug in specific media attachments, like 10bastT or 10base2 or early fiber. Nowadays, one uses SPF ports for a similar concept (pluggable media ports).

Token ring used its own weird hermaphroditic connector before going RJ45.

File:IBM hermaphroditic connector.JPG - Wikipedia

en.m.wikipedia.org

 

[Berwhale]

I think he was referring to ethernet, but hub connected rather than switch connected. Where switches actually deliver packets to the correct device, hubs just connected everything to everything else. All the cables carried all the network traffic.

A hub facilitates a star topology for the physical wiring, but electrically, it's still a bus topology (the same as 'thin' or 'thick' Ethernet) and therefore utilizes Carrier Sense Multiple Access with Collision Detect (CSMA/CD) to mediate terminal access to the network - hence the presence of collision lights on these types of hubs or bridges. It must be almost 30 years since i've encountered anything like this in a commercial installation

With respect to BT OpenReaches FTTP network, this is what the optical splitters look like...

I'm currently planning an upgrade of my 1GbE home network to 2.5GbE with a 10GbE 'backbone'. I borrowed some OM3 LC-LC fibre and a couple of 10GbE SFPs from work to test the cheap Chinese switches i'm going to order from AliExpress...

Links to the cheap switches here: https://linktr.ee/berwhale_network

 

[bloodshoteyed]

to test the cheap Chinese switches i'm going to order from AliExpress...

i wouldn't go down that alley, you can go Mikrotik for cheap instead

 

[Berwhale]

i wouldn't go down that alley, you can go Mikrotik for cheap instead

Yeah, but I'm cheap. I can buy...

Two 8x 2.5GbE + 10 GbE SFP+ web managed switches
One 4x 2.5GbE + 2x 10GbE SFP+ web managed switch
Two M.2 2.5GbE cards for my Dell micro PCs
Two 2.5GbE USB 3.0 adapters for my Synology NAS

...from China for the price of one MicroTik CRS310-8G+2S+IN in the UK.

The MicroTik is very nice, but I think the Chinese switches will be fine for my needs. There's a good article on cheap 2.5GbE switches here: https://www.servethehome.com/the-ul...tgear-hasivo-mokerlink-trendnet-zyxel-tp-link

Plus, the MicroTik has a fan in it

 

[bloodshoteyed]

all that for apx, what, 230€/200£?
sure sounds nice but what about security?

a question, tho...you mentioned m.2 2.5gb cards, haven't seen any that come with a breakout cable to a rj45 connector so far...or did you mean the oem/proprietary cards for 1l machines that come assembled, that slot in take up the upgrade cut-out on the back?

 

[Berwhale]

all that for apx, what, 230€/200£?
sure sounds nice but what about security?

a question, tho...you mentioned m.2 2.5gb cards, haven't seen any that come with a breakout cable to a rj45 connector so far...or did you mean the oem/proprietary cards for 1l machines that come assembled, that slot in take up the upgrade cut-out on the back?

Security from what? Almost everything electronic in my house has come from China.

These are the M.2 2.5GbE cards i've ordered: https://www.aliexpress.com/item/100...o.order_list.order_list_main.5.7a7e1802yNgrpd

I currently have a 1GbE card in my Dell Optiplex 7060 Micro proxmox host...

Note: I had to take the retaining clip off the IDC connector on the ribbon cable as it prevented the SATA drive from fitting. The 2.5GbE NIC I have ordered has the connector pins parallel to the M.2 board and should hopefully avoid this issue.

You can buy similar M.2 cards from a French seller on eBay if you are worried about ordering from direct from China (I sourced the 1GbE card from here)... https://www.ebay.co.uk/str/kaleainformatique

The 7060 will soon be replaced by a Dell Optiplex 3090 i3-1010T Micro which I bought for £118 from eBay yesterday. It appears to be in mint condition and still has over a year of the Dell warranty left on it

 

[bloodshoteyed]

nice, like i've said, haven't seen those before
i only knew of the add-on cards for the expandable slot, marked here on your pic:

but those are rare (and pretty costly) to come by

nice find on the Dell, that's about what i paid for my HP PD G4 minis (incl. a CPU upgrade from a pentium G to an i5 6500T) couple years ago

 

[audio_tony]

@Berwhale Have you heard of FS switches? They seem to be good value for money, and have a UK distributor too.

FS.com United Kingdom - HPC, Data Centre, Enterprise, Telecom

FS is a new brand in Data Centre, Enterprise, Telcom Solutions. We make it easy and cost-effective for IT professionals to enable their business solutions.

www.fs.com

 

[somebodyelse]

Security from what? Almost everything electronic in my house has come from China.

From whatever vulnerabilities emerge and need fixing through firmware updates. Something like https://blog.mikrotik.com/security/cve-2023-32154.html. It tends to be an issue for managed switches, APs and the like. Unmanaged switches tend not to have anything you can upgrade. The hope is that the manufacturer will respond to the vulnerability report and release a fix. The well-known manufacturers tend to at least respond, but at the lower end of their range they may point you to the new model instead of releasing a fix. A lot of the others just don't respond to the notifications, and don't ever release any firmware updates anyway.

 

[Berwhale]

From whatever vulnerabilities emerge and need fixing through firmware updates. Something like https://blog.mikrotik.com/security/cve-2023-32154.html. It tends to be an issue for managed switches, APs and the like. Unmanaged switches tend not to have anything you can upgrade. The hope is that the manufacturer will respond to the vulnerability report and release a fix. The well-known manufacturers tend to at least respond, but at the lower end of their range they may point you to the new model instead of releasing a fix. A lot of the others just don't respond to the notifications, and don't ever release any firmware updates anyway.

These switches will be deployed on an internal network with a pfSense firewall between them and the internet. If someone is 'network-adjacent' enough to exploit a vulnerability of the type you link to, then i'm already toast. If anything, I would be more concerned about supply chain vulnerabilities and the insertion of backdoors by the manufacturer or Chinese state.