Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
Switch: it as an intelligent device. it performs switching actions
Bridge: it is not an intelligent device. it only transfers the data from one point to another. It doesnot performs switching actions
Switch is an intelligent device that read the header of the package and determines if the message must be delivered to the outside, if this is the case it put the message outside, if not nothing happends and the message stays inside the subnetwork.
The hub is a device that gives power to the signal and replicates the messages to eevery other output.
Bridge let pass packages only if the destinatary is in the network the bridge is caring, that deppends of the MAC addres, network card address.
The router has all the above functions and can translate between protocols too. Another feature is the router communicates to other routers and retrieve informations of several destinations, so when ine message arrives, the router send it to the best path.
A network bridge connects multiple network segments (network domains) at the data link layer. It is sometimes called a network switch, and it works by using bridging. Traffic from one network is forwarded through it to another network. The bridge simply does what its name entails, by connecting two sides from adjacent networks.
A repeater is a similar device that connects network segments at the physical layer. An Ethernet hub is a type of repeater.
Bridging takes place at the data link layer of the OSI model. Therefore a bridge can only read the Ethernet header which provides the MAC address of the source and destination address. When a broadcast packet is transmitted, the bridge floods all the ports with the broadcast packets. Bridges use two methods to resolve the network segment that a MAC address belongs to.
* Transparent Bridging – This method uses a forwarding database to send packets across network segments. The forwarding database is initially empty and entries in the database are built as the bridge receives packets. If an address entry is not found in the forwarding table, the packet is flooded to all ports of the bridge which sends the packet to all segments except the source address. This type of bridging is common in Ethernet networks.
* Source route bridging – This method is used in Token Ring networks. Two frame types are used in order to find the route, SR (Single-Route) frame and AR (All-Routes) frame.
In Ethernets, the term "bridge" formally means a device that behaves according to the IEEE 802.1D standard - this is most often referred to as a network switch in marketing literature.
Added after 32 seconds:
An Ethernet hub or concentrator is a device for connecting multiple twisted pair or fibre optic Ethernet devices together, making them act as a single segment. It works at the physical layer of the OSI model, repeating the signal received at one port out each of the other ports (but not the original one). The device is thus a form of multiport repeater. Ethernet hubs are also responsible for forwarding a jam signal to all ports if it detects a collision.
Hubs also often come with a BNC and/or AUI connector to allow connection to legacy 10BASE2 or 10BASE5 network segments. The availability of low-priced Ethernet switches has largely rendered hubs obsolete but they are still seen in older installations and more specialist applications.
Added after 37 seconds:
A network switch (or just switch for short) is a networking device that performs transparent bridging (connection of multiple network segments with forwarding based on MAC addresses) at full wire speed in hardware. The use of specially designed hardware also makes it possible to have large numbers of ports (unlike a PC based bridge which is very limited by expansion slot count).
If a network has only switches and no hubs then the collision domains are either reduced to a single link or, if both ends support full duplex, eliminated altogether. The principle of a fast hardware forwarding device with many ports can be extended to higher layers giving the multilayer switch.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
