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This is openretch (openreach) not Virgin so not sure where you get shared medium from I do know people who worked in radio interference and they told me one ti

This is openretch (openreach) not Virgin so not sure where you get shared medium from I do know people who worked in radio interference and they told me one time they traced a fault to a Budgie cage. The Budgie had a swing and when it was in use it caused a short which effected the subs (customer) line.

bayindirh 6y ago
If you're running network over coax alongside cable TV, it's shared medium. I'm not in the UK or US though, so regardless of their name, every ISP is equal and is indeed a bog standard ISP from my vantage point.
- milankragujevic 6y ago
  BT openreach mainly does DSL and FTTH, AFAIK. edit: Just to clarify, FTTH is by definition a shared medium, but the huge capacity in practice means that there is little congestion usually. Also, since glass fiber is a dielectric, it is difficult to get noise in the signal, and it is immune to EMI. DSL is by definition a dedicated medium, having a twisted pair wire from the DSLAM at the central office or street cabinet to the user premises into the [splitter and] modem. One user per twisted pair only. However, the wires are not shielded and thus are susceptible to both crosstalk from other pairs and also EMI given that it's using electrical signals to transfer data. And of course, the speeds are low for most users due to the local loop length and in general VDSL2 35b maxes out at 300/100 Mbps at around ~80 meters, and VDSL2 17a maxes out at 100/50 Mbps at around 100 meters.
  - LargoLasskhyfv 6y ago
    By that you mean GPON, I guess? Not so here, where it is PTP. And an ISP with excellent peering.
    - milankragujevic 6y ago
      Edit: disregard my comment, I mistook PTP to mean Ethernet while in reality it's Point to point Fiber. In any case my point about noise still stands. But PTP Fiber is really rare in the world, given how many people are stuck on coax. Yes, with FTTH (or FTTP) I meant GPON. Refarding PTP, do you mean a residential ethernet network? (Technically FTTB, copper / ethernet to the premises) Branding anything other than FTTH as "Fiber" is misleading. It's like saying DOCSIS 3.0 is Fiber because its a Hybrid Fiber-Coaxial network, while in reality all cable internet networks are HFC, the difference is the number of nodes serviced by a CMTS, which when reduced by a node split will result in higher speeds and more capacity. Or saying DSL is "Fiber" because uplink to the DSLAM is Fiber. All DSLAM uplinks are Fiber, difference is how many street cabinets are there because DSL speed is dictated by the local loop length, and with more street cabinets there is higher chance one gets built closer to you enabling you faster speeds.
      - LargoLasskhyfv 6y ago
        I meant a residential fiber network, where the fiber really goes into the home, and the topology of that network is point-to-point. As in from some POP(point-of-presence) from ISP into the home, not over shared channels like in GPON. My ISP is rolling that out, though with delays. They are a spin-off of a public utility. Already rolled out the CPE looks like this: https://genexis.eu/product/fibertwist/ https://genexis.eu/product/fibertwist/ and in the user-forum of that ISP there are people describing how to directly interface to fiber with a pre-fabricated cable and SFP-transceiver with the right wavelengths, from a self-owned router with SFP-cage. But you still have to connect over PPPoE with a MTU of 1492 bytes. Multiple times actually, on different VLANs for management, VoIP, and public dynamic IPv4(CGNAT)/IPv6(native/64)
        milankragujevic 6y ago
        Understood. Sorry for the confusion. RE: PPPoE - in general most AAA systems already work with PPP and since ISPs generally have to support legacy infrastructure too, and multiple access technologies, they "force" all users to connect with PPPoE for billing and data collection for identification. For example, a national ISP in my country uses PPP for xDSL (which is a dedicated medium) and GPON (which is a shared medium, however the authorization and speed limiting is done by the ONT S/N), none of which "need it". You can also mix GPON and DSL logins and it will work, even between users. The only logical reason for this, from what I can see, is that they are forced to sell access to their infrastructure (being an ILEC) to other ISPs, so they use PPP to route traffic from users of other ISPs from the BRAS to the corresponding network gateway using a MPLS tunnel. For business fiber, not based on xPON, there is no requirement for a PPP session, and instead you get assigned an IP address range that you router should use, and the fiber is connected with a SFP+ module to your router. On the ISP's side, your "port" is limited to accessing their intranet for management and remote control, and your assigned IP address range.
- iso1631 6y ago
  Cable TV? Coax? Most of the UK, especially outside of large towns, is 1) Twisted pair to the cabinet then Twisted pair to the exchange ("Normal DSL", ADSL) 2) Twisted pair to the cabinet then Fibre to the exchange ("Fibre broadband", FTTC) 3) Fibre to the cabinet then Fibre to the exchange (FTTP) Cable TV is a minority thing in the UK, maybe 20% of TV owning households, compared with 50% on satelite of some sort, and 95% on terrestial.
  - tialaramex 6y ago
    > 3) Fibre to the cabinet then Fibre to the exchange (FTTP) FTTP doesn't bother going to a cabinet at all since there would be nothing interesting for it to do there. GPON splitters are low maintenance and so you can just throw one up on a telegraph pole or bury it. Yes this means that an era of street cabinets gives way to an era in which it's just telegraph poles or the network infrastructure disappears entirely, buried in the street. > Cable TV is a minority thing in the UK, maybe 20% of TV owning households. This may well be, however over 50% of UK households could buy their Internet service from Virgin (the Cable TV company) and get DOCSIS over that coaxial cable, they needn't choose to buy television service (although of course Virgin would like them to do so)
- C1sc0cat 6y ago
  coax ? how quaint - there may be a small number of customers on actual coax but this is about Openreach part of BT's plant which will be POTS copper. Unless they actually mean that tv blew away everyone's wifi, which is impressive but unlikely.

bayindirh 6y ago

If you're running network over coax alongside cable TV, it's shared medium. I'm not in the UK or US though, so regardless of their name, every ISP is equal and is indeed a bog standard ISP from my vantage point.

milankragujevic 6y ago
BT openreach mainly does DSL and FTTH, AFAIK. edit: Just to clarify, FTTH is by definition a shared medium, but the huge capacity in practice means that there is little congestion usually. Also, since glass fiber is a dielectric, it is difficult to get noise in the signal, and it is immune to EMI. DSL is by definition a dedicated medium, having a twisted pair wire from the DSLAM at the central office or street cabinet to the user premises into the [splitter and] modem. One user per twisted pair only. However, the wires are not shielded and thus are susceptible to both crosstalk from other pairs and also EMI given that it's using electrical signals to transfer data. And of course, the speeds are low for most users due to the local loop length and in general VDSL2 35b maxes out at 300/100 Mbps at around ~80 meters, and VDSL2 17a maxes out at 100/50 Mbps at around 100 meters.
- LargoLasskhyfv 6y ago
  By that you mean GPON, I guess? Not so here, where it is PTP. And an ISP with excellent peering.
  - milankragujevic 6y ago
    Edit: disregard my comment, I mistook PTP to mean Ethernet while in reality it's Point to point Fiber. In any case my point about noise still stands. But PTP Fiber is really rare in the world, given how many people are stuck on coax. Yes, with FTTH (or FTTP) I meant GPON. Refarding PTP, do you mean a residential ethernet network? (Technically FTTB, copper / ethernet to the premises) Branding anything other than FTTH as "Fiber" is misleading. It's like saying DOCSIS 3.0 is Fiber because its a Hybrid Fiber-Coaxial network, while in reality all cable internet networks are HFC, the difference is the number of nodes serviced by a CMTS, which when reduced by a node split will result in higher speeds and more capacity. Or saying DSL is "Fiber" because uplink to the DSLAM is Fiber. All DSLAM uplinks are Fiber, difference is how many street cabinets are there because DSL speed is dictated by the local loop length, and with more street cabinets there is higher chance one gets built closer to you enabling you faster speeds.
    - LargoLasskhyfv 6y ago
      I meant a residential fiber network, where the fiber really goes into the home, and the topology of that network is point-to-point. As in from some POP(point-of-presence) from ISP into the home, not over shared channels like in GPON. My ISP is rolling that out, though with delays. They are a spin-off of a public utility. Already rolled out the CPE looks like this: https://genexis.eu/product/fibertwist/ https://genexis.eu/product/fibertwist/ and in the user-forum of that ISP there are people describing how to directly interface to fiber with a pre-fabricated cable and SFP-transceiver with the right wavelengths, from a self-owned router with SFP-cage. But you still have to connect over PPPoE with a MTU of 1492 bytes. Multiple times actually, on different VLANs for management, VoIP, and public dynamic IPv4(CGNAT)/IPv6(native/64)
      - milankragujevic 6y ago
        Understood. Sorry for the confusion. RE: PPPoE - in general most AAA systems already work with PPP and since ISPs generally have to support legacy infrastructure too, and multiple access technologies, they "force" all users to connect with PPPoE for billing and data collection for identification. For example, a national ISP in my country uses PPP for xDSL (which is a dedicated medium) and GPON (which is a shared medium, however the authorization and speed limiting is done by the ONT S/N), none of which "need it". You can also mix GPON and DSL logins and it will work, even between users. The only logical reason for this, from what I can see, is that they are forced to sell access to their infrastructure (being an ILEC) to other ISPs, so they use PPP to route traffic from users of other ISPs from the BRAS to the corresponding network gateway using a MPLS tunnel. For business fiber, not based on xPON, there is no requirement for a PPP session, and instead you get assigned an IP address range that you router should use, and the fiber is connected with a SFP+ module to your router. On the ISP's side, your "port" is limited to accessing their intranet for management and remote control, and your assigned IP address range.
iso1631 6y ago
Cable TV? Coax? Most of the UK, especially outside of large towns, is 1) Twisted pair to the cabinet then Twisted pair to the exchange ("Normal DSL", ADSL) 2) Twisted pair to the cabinet then Fibre to the exchange ("Fibre broadband", FTTC) 3) Fibre to the cabinet then Fibre to the exchange (FTTP) Cable TV is a minority thing in the UK, maybe 20% of TV owning households, compared with 50% on satelite of some sort, and 95% on terrestial.
- tialaramex 6y ago
  > 3) Fibre to the cabinet then Fibre to the exchange (FTTP) FTTP doesn't bother going to a cabinet at all since there would be nothing interesting for it to do there. GPON splitters are low maintenance and so you can just throw one up on a telegraph pole or bury it. Yes this means that an era of street cabinets gives way to an era in which it's just telegraph poles or the network infrastructure disappears entirely, buried in the street. > Cable TV is a minority thing in the UK, maybe 20% of TV owning households. This may well be, however over 50% of UK households could buy their Internet service from Virgin (the Cable TV company) and get DOCSIS over that coaxial cable, they needn't choose to buy television service (although of course Virgin would like them to do so)
C1sc0cat 6y ago
coax ? how quaint - there may be a small number of customers on actual coax but this is about Openreach part of BT's plant which will be POTS copper. Unless they actually mean that tv blew away everyone's wifi, which is impressive but unlikely.