![]() ![]() Up to 1:64 splits are common, depending on overall fiber length and power budget, up to 1:256 is possible. Each 1:2 split attenuates the signal by (at least) 3 dB. With PON, the splitter is a passive, unpowered unit that optically splits the downstream light into multiple, weaker rays. Technically, there's no copying to the various strands. I would greatly appreciate it if people would please take the time to clarify these points. So the incoming packets arrive at the OLT, and then move onto the optical splitter, where they are first each copied before being sent to the addressed ONT? Is it not inefficient to copy the packets in this way? Would it not be more efficient for the packets to just move directly to the addressed ONT, rather than having to be copied at the optical splitter? And I also wonder if there are encryption issues here: If the packets are encrypted, then how can they be copied precisely? Does copying the packets not necessitate knowing the contents, and therefore breaking the encryption? This is my first exposure to computer networking, so please excuse the elementary nature of my questions. In the PON architecture, all packets sent from OLT to the splitter are replicated at the splitter (similar to a cable head end). It is this part that I found interesting: In the home, users connect a home router (typically a wireless router) to the ONT and access the Internet via this home router. ![]() The OLT, proving conversion between optical and electrical signals, connects to the internet via a telco router. The splitter combines a number of homes (typically less than 100) onto a single, shared optical fibre, which connects to an optical line terminator (OLT) in the telco's CO. Each home has an optical network terminator (ONT), which is connected by dedicated optical fibre to a neighborhood splitter. Figure 1.7 shows FTTH using the PON distribution architecture. Here, we briefly discuss PON, which is used in Verizon's FIOS service. ![]() AON is essentially switched Ethernet, which is discussed in Chapter 6. There are two competing optical-distribution network architectures that perform this splitting: active optical networks (AONs) and passive optical networks (PONs). More commonly, each fibre leaving the central office is actually shared by many homes it is not until the finer gets relatively close to the homes that it is split into individual customer-specific fibres. The simplest optical distribution network is called direct fibre, with one fibre leaving the CO for each home. There are several competing technologies for optical distribution from the CO to the homes. In a chapter on Home Access: DSL, Cable, FTTH, Dial-Up, and Satellite, the authors say the following: I am currently studying the textbook Computer Networking - A Top-Down Approach (7th Edition) by Kurose and Ross. ![]()
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