Is network A an SDH optical transmission network in optical cable communication?

1, a, the optical transmission system consists of 3 parts, optical fiber transmission medium, light source and detector. 2,a3,b4,d,multiple,5,a can be achieved through the port number that does not pass 5,aI wish you a smooth exam.

A fiber optic transport network simply provides a transmission medium on which any Layer 2 protocol can run. SDH is a framed network, on which other Layer 2 protocols can be run, and Layer 3 protocol data can be directly run.

SDH over WDM, WDM is a wavelength division, an optical signal running multiple wavelengths on an optical fiber, the main purpose of which is to increase the bandwidth of transmission.

What is SDH Transport?

SDH (Synchronous Digital Hierarchy) is a comprehensive information transmission network that integrates multiplexing, line transmission and switching functions and is operated by a unified network management system. The International Telegraph Advisory Committee (CCITT) (now ITU-T) accepted the SONET concept in 1988 and renamed it SDH, making it a universal technical regime for not only fiber optics but also microwave and satellite transmission.

What are the basic network elements of SDH?

NE subnet.

The transmission part of the NE--- the multiplexing part, the clock part, and the intersection part.

SDH is suitable for point-to-point transmission and network transmission between multiple points. The topology of the SDH transport network, which is composed of SDH termination equipment (or SDH terminal multiplexerTM), add-drop multiplexing equipment ADM, digital cross-connect equipment DXC and other network elements, as well as the (optical fiber) physical link connecting them.

The main functions of SDH terminals are to multiplex and tap and provide service adaptation, such as multiplexing multiple E1 signals into STM1 signals and completing their reverse process, or realizing adaptation to non-SDH network services. ADM is a special multiplexer that uses tap-and-switch to split the information carried by the input signal into two parts: one directly and the other offloaded to the local user.

Then the information is synthesized and output by the multiplexing function to the ** part and the locally sent part. A DXC is similar to a switch in that it typically has multiple inputs and multiple outputs, providing different end-to-end connectivity when properly configured. The functional block diagrams of TM, ADM, and DXC are shown in Figures (a), (b), and (c), respectively.

1. DDF (digital distribution frame) is a wiring connection equipment between digital multiplexing equipment, between digital multiplexing equipment and other professional equipment such as program-controlled switching equipment or data service equipment. Digital distribution frame, also known as high-frequency distribution frame, is more and more superior in digital communication, it can make the connection of digital code stream of digital communication equipment become a whole, from the rate of 2 MB s 155 MB s signal input, output can be terminated on the DDF rack, which brings great flexibility and convenience for wiring, wire adjustment, transfer, and expansion.

2. ODF (optical distribution frame, optical fiber distribution frame) is used for the ending and distribution of the backbone optical cable in the optical fiber communication system, which can easily realize the connection, distribution and scheduling of optical fiber lines.

3. SDH (Synchronous Digital Hierarchy), defined according to the ITU-T recommendations, is a technical system composed of the transmission of digital signals of different speeds to provide a corresponding level of information structure, including multiplexing methods and mapping methods, as well as related synchronization methods.

ddf digital distribution frame

It seems, for a long time, I forgot, digital patch panel.

odf optical distribution frame

Fiber optic patch panels.

sdh synchronous digital hierarchy

Synchronize digital sequences.

SDH is a synchronous time-division multiplexing device, which converts and multiplexes the 2M signal of the electrical interface into a high-speed signal (155M, 622M, 10G, etc.) of the optical port.

The 2 trillion signal can be jumped on the DDF for easy connection.

The optical path signal is jumped on the ODF and interconnected with the optical interface of the optical cable or other equipment.

The usual use of the network, ** and so on are specific services, their communication distance is limited, generally through the transmission network to carry to expand the communication capacity, extend the communication distance.

SDH is the main equipment of the current transmission network, and DDF and ODF are mainly used for jumpers in the equipment room, which is regarded as the physical interface between the devices.

bts－ddf-sdh-ddf-bsc-odf-msc

or bts-ddf-sdh-odf-bsc-odf-msc

Of course, there may also be a ODF-SDH-ODF between BSC and MSC, depending on the situation.

An optical fiber enters the computer room, advanced ODF optical fiber distribution box, and then converts it into electrical signals through the pigtail to SDH photoelectricity, and then through the 2M line in the DDF rack (the DDF rack is used for transfer), and then to the BTS

ODF Optical Distribution Frame.

SDH Synchronous Digital Hierarchy.

The diagram of the communication system in the base station looks like this:

bts--ddf--sdh--odf--- another direction. Downward.

BTS is a 2G base station, a wireless network is composed of N BTS and several BSCs, each BTS needs to access the base station through the transmission network, and the transmission interface is mostly 2M interface.

SDH (Synchronous Digital Hierarchy) is a technical system formulated by the ITU and a transmission technology. The SDH line side (that is, the outgoing optical cable) is 155m, 622m, and optical interfaces. On the branch side (connected to the service network equipment, including the base station), most of them are 2M, FE, GE, and 155M optical interfaces.

DDF and ODF are both patch panels, DDF digital patch panels, ODF fiber optic patch panels. The SDH line is connected to the ODF rack on the side, which is connected to the outbound optical cable, and the DDF rack is connected to the service network equipment, which is connected to the BTS in the base station. The main purpose of setting up the patch panel is for easy maintenance, you can label the patch panel, and the business type of each interface is clear.

The diagram of the communication system in the base station looks like this:

bts--ddf--sdh--odf--- another direction.

A transport network should be a network that provides a service. It's like the relationship between the railroad and the train station that the seniors upstairs said. Railway stations are serviced by rail.

I also started with computer networks and learned about Layer 2 switching and Layer 3 routing. Transport networks are not well understood.

In a computer network, two adjacent routers are connected by a single wire by default. Of course, small networks can be connected in this way, just get a network cable, so the campus network and campus network are built in this way. However, how to achieve the deployment of large networks is a difficult problem of funding and policy.

However, routers can take advantage of the existing network, which is the optical fiber communication network SDH, which has long been widely used throughout the country. The router is a concept in the computer network, which can be used to look up the table according to the IP address, while SDH is a traditional communication network, which was once only built for voice services.

Therefore, the network bearer technology of IP over SDH was proposed.

Therefore, it solves the problem of long-distance transmission between routers with adjacent hops.

Therefore, from the perspective of the OSI model, SDH can be regarded as the line between the two routers, that is, the physical layer technology.

In fact, SDH is a network system with its own hierarchical mechanism, just like SF Express, Router A hands over MAC packets to SDH devices, and then regardless of SDH operations, it can finally hand over MAC packets to Router B.

It is worth noting that this SDH is a system, and it also has its own network layering in the field of telecommunication network, as well as functions such as rapid switchover after the link is broken, which is quite reliable. Of course, for the router of the adjacent hop, SDH is a courier who receives and sends courier.

SDH is composed of ADM and DXC, so its self-healing ability and reorganization function are very powerful, and its network management function is very powerful, forming a unified network management system. DXC is similar to a switch (the router can also be used as a switch) with multiple inputs and multiple outputs, while the router has an additional Internet access distribution function. ADM is the equivalent of its function is to take the signal ** and offload it to the local user.

See the reference material for its connection diagram.

As a simple example, the relationship between a transport network and a router is like that between a train station and a railway. Everyone is on the train station to board the train to go and then take you to where you are going by rail. The railway station is the router, and the railway network is the transmission network.

The transport network is located at the lowest level of the OSI - the physical layer and is only responsible for transmission.

Through this simple analogy, you should be able to understand the relationship between the two.

SDH is between Layer 1 and Layer 2, but routers generally belong to Layer 3.

SDH is equivalent to the train being transported, and Ethernet data, V35 data, E1, etc. are equivalent to boxes loaded on the train.

For example, SDH is the equivalent of the cloud you see on the charts of various textbooks.

Optical fiber communication is from the transmission medium of the network; (It can be Ethernet, Token Network, etc.).

Ethernet is in terms of communication protocols; (It can be optical fiber, it can also be a Category 5 cable, etc.).

Needless to say, fiber optic Ethernet... The media and protocols are there.