How does a Subscriber’s Internet travel from Service Provider Perspective#

As with everything it depends on the solution provided - Fibre, Adsl and Wireless technology like 3g, 4g and LTE

Looking from a Fibre perspective the flow is:

ONT -> OLT -> ENNI -> RADIUS -> BNG -> PACKET INTROSPECTION - P ROUTER - PEERING/IP TRANSIT

So let us go through what the above are:

  • ONT (Optical Network Terminal) - device at subscriber’s home that converts optical signals into electrical signals
  • OLT (Optical Line Terminal) - convert, frame, and transmit signals for the PON network and to coordinate the optical network terminals multiplexing for the shared upstream transmission
  • ENNI (External Network-to-Network Interface) - The boundary between 2 operators. Layer 2 Vlan is handed off.
  • Radius - Speaks to the BNG to authenticate subscribers
  • BNG (Broadband Network Gateway) - the access point for customers to connect to the broadband network
  • PACKET INTROSPECTION - Inspects all traffic and stores amount of traffic used for subscribers
  • P ROUTER (Provider Router) - Provide reachability between Provider Edge devices
  • PEERING / IP TRANSIT - IP transit is when one entity pays another for the right to transit its upstream network (One entity is higher than the other on the chain). IP peering is a mutual exchange of data between two ISPs.

Sources#