Dicograff Squad

Seni grafis(stencil) adalah cabang seni rupa yang proses pembuatan karyanya menggunakan teknik cetak, biasanya di atas kertas. Kecuali pada teknik Monotype, prosesnya mampu menciptakan salinan karya yang sama dalam jumlah banyak, ini yang disebut dengan proses cetak. Tiap salinan karya dikenal sebagai ‘impression’. Lukisan atau drawing, di sisi lain, menciptakan karya seni orisinil yang unik. Cetakan diciptakan dari permukaan sebuah bahan , secara teknis disebut dengan matrix. Matrix yang umum digunakan adalah: plat logam, biasanya tembaga atau seng untuk engraving atau etsa; batu digunakan untuk litografi; papan kayu untuk woodcut/cukil kayu. Masih banyak lagi bahan lain yang digunakan dalam karya seni ini. Tiap-tiap hasil cetakan biasanya dianggap sebagai karya seni orisinil, bukan sebuah salinan. Karya-karya yang dicetak dari sebuah plat menciptakan sebuah edisi, di masa seni rupa modern masing-masing karya ditandatangani dan diberi nomor untuk menandai bahwa karya tersebut adalah edisi terbatas.
media
Seniman grafis berkarya menggunakan berbagai macam media dari yang tradisional sampai kontemporer, termasuk tinta ber-basis air, cat air, tinta ber-basis minyak, pastel minyak, dan pigmen padat yang larut dalam air seperti crayon Caran D’Ache. Karya seni grafis diciptakan di atas permukaan yang disebut dengan plat. Teknik dengan menggunakan metode digital menjadi semakin populer saat ini. Permukaan atau matrix yang dipakai dalam menciptakan karya grafis meliputi papan kayu, plat logam, lembaran kaca akrilik, lembaran linoleum atau batu litografi. Teknik lain yang disebut dengan serigrafi atau cetak saring (screen-printing) menggunakan lembaran kain berpori yang direntangkan pada sebuah kerangka, disebut dengan screen. Cetakan kecil bahkan bisa dibuat dengan menggunakan permukaan kentang atau ketela.

warna

Pembuat karya grafis memberi warna pada cetakan mereka dengan banyak cara. Seringkali pewarnaannya — dalam etsa, cetak saring, cukil kayu serta linocut — diterapkan dengan menggunakan plat, papan atau screen yang terpisah atau dengan menggunakan pendekatan reduksionis. Dalam teknik pewarnaan multi-plat, terdapat sejumlah plat, screen atau papan, yang masing-masing menghasilkan warna yang berbeda. Tiap plat, screen atau papan yang terpisah akan diberi tinta dengan warna berbeda kemudian diterapkan pada tahap tertentu untuk menghasilkan keseluruhan gambar. Rata-rata digunakan 3 sampai 4 plat, tapi adakalanya seorang seniman grafis menggunakan sampai dengan tujuh plat. Tiap penerapan warna akan berinteraksi dengan warna lain yang telah diterapkan pada kertas, jadi sebelumnya perlu dipikirkan pemisahan warna. Biasanya warna yang paling terang diterapkan lebih dulu kemudian ke warna yang lebih gelap.
Pendekatan reduksionis untuk menghasilkan warna dimulai dengan papan kayu atau lino yang kosong atau dengan goresan sederhana. Kemudian seniman mencukilnya lebih lanjut, memberi warna lain dan mencetaknya lagi. Bagian lino atau kayu yang dicukil akan mengekspos (tidak menimpa) warna yang telah tercetak sebelumnya.
Pada teknik grafis seperti chine-collé atau monotype, pegrafis kadang-kadang hanya mengecat warna seperti pelukis kemudian dicetak.
Konsep warna subtraktif yang juga digunakan dalam cetak offset atau cetak digital, di dalam software vektorial atau bitmap ditampilkan dalam CMYK atau ruang warna lain.

Secara umum, pembuatan graffiti dibuat dengan outlining dulu. Ada banyak buku yang membahas tentang teknik-teknik outlining yang canggih-canggih, tapi dasar dari outlining adalah sebagai berikut.
Saat yang tepat untuk melakukan outlining adalah di awal dan di akhir pembuatan graffiti. Outline di awal adalah sebagai guide untuk memandu flow kita dalam membuat graffiti. Dengan outline awal itu kita jadi tahu dimana filling harus dilakukan. Setelah kita selesai membuat outline awal, tentunya setelah itu kita akan menggarap filling, background, 3D, touch-up dan yang lain-lainnya. Semua itu bukan tidak mungkin akan sedikit menutupi dan mengacaukan outline awal.
Jadi sebaiknya di akhir graffiti, re-trace lagi outline untuk mendapatkan gambar yang maksimal rapihnya. Tapi pastikan dulu semua sudah dilakukan sebelum re-trace. Jadi re-trace benar-benar dilakukan di paling akhir.
Saat melakukan outlining, posisi spray yang terbaik adalah paralel dengan tembok dan kalau bisa sedekat mungkin agar garisnya tegas dan tajam.
Outline yang pertama adalah yang akan paling menggambarkan hasil akhir graffiti kita, jadi jangan ragu untuk menghabiskan banyak waktu di outline awal. Jika salah mengambil garis, buatlah garis baru dan pastikan garis yang salah itu bisa ditutupi dengan filling nantinya,

Grafiti (juga dieja graffity atau graffiti) adalah coretan-coretan pada dinding yang menggunakan komposisi warna, garis, bentuk, dan volume untuk menuliskan kata, simbol, atau kalimat tertentu. Alat yang digunakan pada masa kini biasanya cat semprot kaleng. Sebelum cat semprot tersedia, grafiti umumnya dibuat dengan sapuan cat menggunakan kuas atau kapur.
Sejarah


Grafiti di Pompeii. Grafiti ini mengandung tulisan rakyat yang menggunakan bahasa Latin Rakyat dan bukan bahasa Latin Klasik.
Kebiasaan melukis di dinding bermula dari manusia primitif sebagai cara mengkomunikasikan perburuan. Pada masa ini, grafitty digunakan sebagai sarana mistisme dan spiritual untuk membangkitkan semangat berburu.
Perkembangan kesenian di zaman Mesir kuno juga memperlihatkan aktivitas melukis di dinding-dinding piramida. Lukisan ini mengkomunikasikan alam lain yang ditemui seorang pharaoh (Firaun) setelah dimumikan.
Kegiatan grafiti sebagai sarana menunjukkan ketidak puasan baru dimulai pada zaman Romawi dengan bukti adanya lukisan sindiran terhadap pemerintahan di dinding-dinding bangunan. Lukisan ini ditemukan di reruntuhan kota Pompeii. Sementara di Roma sendiri dipakai sebagai alat propaganda untuk mendiskreditkan pemeluk kristen yang pada zaman itu dilarang kaisar.



Adanya kelas-kelas sosial yang terpisah terlalu jauh menimbulkan kesulitan bagi masyarakat golongan tertentu untuk mengekspresikan kegiatan seninya. Akibatnya beberapa individu menggunakan sarana yang hampir tersedia di seluruh kota, yaitu dinding.
Pendidikan kesenian yang kurang menyebabkan objek yang sering muncul di grafiti berupa tulisan-tulisan atau sandi yang hanya dipahami golongan tertentu. Biasanya karya ini menunjukkan ketidak puasan terhadap keadaan sosial yang mereka alami.
Meskipun grafiti pada umumnya bersifat merusak dan menyebabkan tingginya biaya pemeliharaan kebersihan kota, namun grafiti tetap merupakan ekspresi seni yang harus dihargai. Ada banyak sekali seniman terkenal yang mengawali kariernya dari kegiatan grafiti.
Fungsi grafiti
• Bahasa rahasia kelompok tertentu.
• Sarana ekspresi ketidak puasan terhadap keadaan sosial.
• Sarana pemberontakan.
• Sarana ekspresi ketakutan terhadap kondisi politik dan sosial.
Hukum


Grafiti yang dibuat sebagai bentuk penolakan terhadap RUU APP
Pada perkembangannya, grafiti di sekitar tahun 70-an di Amerika dan Eropa akhirnya merambah ke wilayah urban sebagai jati diri kelompok yang menjamur di perkotaan. Karena citranya yang kurang bagus, grafiti telanjur menjadi momok bagi keamanan kota. Alasannya adalah karena dianggap memprovokasi perang antar kelompok atau gang. Selain dilakukan di tembok kosong, grafiti pun sering dibuat di dinding kereta api bawah tanah.
Di Amerika Serikat sendiri, setiap negara bagian sudah memiliki peraturan sendiri untuk meredam grafiti. San Diego, California, New York telah memiliki undang-undang yang menetapkan bahwa grafiti adalah kegiatan ilegal. Untuk mengidentifikasi pola pembuatannya, grafiti pun dibagi menjadi dua jenis.
Gang grafiti
Yaitu grafiti yang berfungsi sebagai identifikasi daerah kekuasaan lewat tulisan nama gang, gang gabungan, para anggota gang, atau tulisan tentang apa yang terjadi di dalam gang itu.
Tagging graffiti
Yaitu jenis graffiti yang sering dipakai untuk ketenaran seseorang atau kelompok. Semakin banyak graffiti jenis ini bertebaran, maka makin terkenallah nama pembuatnya. Karena itu grafiti jenis ini memerlukan tagging atau tanda tangan dari pembuat atau bomber-nya. Semacam tanggung jawab karya.
Mural

Mural adalah cara menggambar atau melukis di atas media dinding, tembok atau permukaan luas yang bersifat permanen lainnya.
Berbeda dengan grafiti yang lebih menekankan hanya pada isi tulisan dan kebanyakan dibuat dengan cat semprot maka mural tidak demikian, mural lebih bebas dan dapat menggunakan media cat tembok atau cat kayu bahkan cat atau pewarna apapun juga seperti kapur tulis atau alat lain yang dapat menghasilkan gambar.
Fresko
Fresko adalah teknik melukis pada dinding dengan menimpakan pigmen pada plaster dinding yang baru dilapisi. Kemudian definisi ini sedikit berubah karena Leonardo da Vinci memperkenalkan teknik baru dengan menimpakan pigmen warna kepada lapisan yang telah kering dengan sedikit modifikasi.
Fresko berasal dari frase Italia buon fresco yang berarti "selagi basah". Pigmen yang ditimpakan di atas plaster basah akan melekat sangat kuat sehingga hasil karya bisa dinikmati berpuluh tahun. Adonan ini harus dibuat dengan takaran yang tepat, sebab bila terlalu basah akan menyebabkan timbulnya jamur, dan bila terlalu kering akan menyebabkan pigmen tidak bisa tertempel kuat.
Desain fresko biasanya dibuat pada bagian atas kertas yang kemudian dilubangi, ditempelkan ke atas plaster basah, dan ditaburi pigmen gelap yang kemudian membuat pola desain yang persis sama dengan rancangan semula. Lukisan harus dibuat secepat mungkin sebelum adonan plester mengering sehingga saat sebagian air diserap oleh dinding, pigmen yang ada juga ikut terserap dengan kua

Computer network

A computer network, often simply referred to as a network, is a collection of computers and devices connected by communications channels that facilitates communications among users and allows users to share resources with other users. Networks may be classified according to a wide variety of characteristics.
Introduction
A computer network allows sharing of resources and information among devices connected to the network. In the 1960s, the Advanced Research Projects Agency (ARPA) started funding the design of the Advanced Research Projects Agency Network (ARPANET) for the United States Department of Defense. It was the first operational computer network in the world. Development
Purpose
Computer networks can be used for several purposes:
• Facilitating communications. Using a network, people can communicate efficiently and easily via email, instant messaging, chat rooms, telephone, video telephone calls, and video conferencing.
• Sharing hardware. In a networked environment, each computer on a network may access and use hardware resources on the network, such as printing a document on a shared network printer.
• Sharing files, data, and information. In a network environment, authorized user may access data and information stored on other computers on the network. The capability of providing access to data and information on shared storage devices is an important feature of many networks.
• Sharing software. Users connected to a network may run application programs on remote computers.
Network classification
The following list presents categories used for classifying networks.
Connection method
Computer networks can be classified according to the hardware and software technology that is used to interconnect the individual devices in the network, such as optical fiber, Ethernet, Wireless LAN, HomePNA, Power line communication or G.hn.
Ethernet uses physical wiring to connect devices. Frequently deployed devices include hubs, switches, bridges and/or routers. Wireless LAN technology is designed to connect devices without wiring. These devices use radio waves or infrared signals as a transmission medium. ITU-T G.hn technology uses existing home wiring (coaxial cable, phone lines and power lines) to create a high-speed (up to 1 Gigabit/s) local area network.
Wired technologies
• Twisted pair wire is the most widely used medium for telecommunication. Twisted-pair wires are ordinary telephone wires which consist of two insulated copper wires twisted into pairs and are used for both voice and data transmission. The use of two wires twisted together helps to reduce crosstalk and electromagnetic induction. The transmission speed ranges from 2 million bits per second to 100 million bits per second.
• Coaxial cable is widely used for cable television systems, office buildings, and other worksites for local area networks. The cables consist of copper or aluminum wire wrapped with insulating layer typically of a flexible material with a high dielectric constant, all of which are surrounded by a conductive layer. The layers of insulation help minimize interference and distortion. Transmission speed range from 200 million to more than 500 million bits per second.
• Optical fiber cable consists of one or more filaments of glass fiber wrapped in protective layers. It transmits light which can travel over extended distances. Fiber-optic cables are not affected by electromagnetic radiation. Transmission speed may reach trillions of bits per second. The transmission speed of fiber optics is hundreds of times faster than for coaxial cables and thousands of times faster than a twisted-pair wire.
Wireless technologies
• Terrestrial Microwave – Terrestrial microwaves use Earth-based transmitter and receiver. The equipment look similar to satellite dishes. Terrestrial microwaves use low-gigahertz range, which limits all communications to line-of-sight. Path between relay stations spaced approx. 30 miles apart. Microwave antennas are usually placed on top of buildings, towers, hills, and mountain peaks.
• Communications Satellites – The satellites use microwave radio as their telecommunications medium which are not deflected by the Earth's atmosphere. The satellites are stationed in space, typically 22,000 miles (for geosynchronous satellites) above the equator. These Earth-orbiting systems are capable of receiving and relaying voice, data, and TV signals.
• Cellular and PCS Systems – Use several radio communications technologies. The systems are divided to different geographic areas. Each area has a low-power transmitter or radio relay antenna device to relay calls from one area to the next area.
• Wireless LANs – Wireless local area network use a high-frequency radio technology similar to digital cellular and a low-frequency radio technology. Wireless LANs use spread spectrum technology to enable communication between multiple devices in a limited area. An example of open-standards wireless radio-wave technology is IEEE
• Infrared communication , which can transmit signals between devices within small distances not more than 10 meters peer to peer or ( face to face ) without any body in the line of transmitting.
Scale
Networks are often classified as local area network (LAN), wide area network (WAN), metropolitan area network (MAN), personal area network (PAN), virtual private network (VPN), campus area network (CAN), storage area network (SAN), and others, depending on their scale, scope and purpose, e.g., controller area network (CAN) usage, trust level, and access right often differ between these types of networks. LANs tend to be designed for internal use by an organization's internal systems and employees in individual physical locations, such as a building, while WANs may connect physically separate parts of an organization and may include connections to third parties.
Functional relationship (network architecture)
Computer networks may be classified according to the functional relationships which exist among the elements of the network, e.g., active networking, client–server and peer-to-peer (workgroup) architecture.
Network topology
Main article: Network topology
Computer networks may be classified according to the network topology upon which the network is based, such as bus network, star network, ring network, mesh network. Network topology is the coordination by which devices in the network are arranged in their logical relations to one another, independent of physical arrangement. Even if networked computers are physically placed in a linear arrangement and are connected to a hub, the network has a star topology, rather than a bus topology. In this regard the visual and operational characteristics of a network are distinct. Networks may be classified based on the method of data used to convey the data, these include digital and analog networks.
Types of networks based on physical scope
Common types of computer networks may be identified by their scale.
Personal area network
A personal area network (PAN) is a computer network used for communication among computer and different information technological devices close to one person. Some examples of devices that are used in a PAN are personal computers, printers, fax machines, telephones, PDAs, scanners, and even video game consoles. A PAN may include wired and wireless connections between devices. The reach of a PAN typically extends to 10 meters. A wired PAN is usually constructed with USB and Firewire connections while technologies such as Bluetooth and infrared communication typically form a wireless PAN
Local area network
A local area network (LAN) is a network that connects computers and devices in a limited geographical area such as home, school, computer laboratory, office building, or closely positioned group of buildings. Each computer or device on the network is a node. Current wired LANs are most likely to be based on Ethernet technology, although new standards like ITU-T G.hn also provide a way to create a wired LAN using existing home wires (coaxial cables, phone lines and power lines).


Typical library network, in a branching tree topology and controlled access to resources
All interconnected devices must understand the network layer (layer 3), because they are handling multiple subnets (the different colors). Those inside the library, which have only 10/100 Mbit/s Ethernet connections to the user device and a Gigabit Ethernet connection to the central router, could be called "layer 3 switches" because they only have Ethernet interfaces and must understand IP. It would be more correct to call them access routers, where the router at the top is a distribution router that connects to the Internet and academic networks' customer access routers.
The defining characteristics of LANs, in contrast to WANs (Wide Area Networks), include their higher data transfer rates, smaller geographic range, and no need for leased telecommunication lines. Current Ethernet or other IEEE 802.3 LAN technologies operate at speeds up to 10 Gbit/s. This is the data transfer rate. IEEE has projects investigating the standardization of 40 and 100 Gbit/.
Home area network
A home area network (HAN)is a residential LAN which is used for communication between digital devices typically deployed in the home, usually a small number of personal computers and accessories, such as printers and mobile computing devices. An important function is the sharing of Internet access, often a broadband service through a CATV or Digital Subscriber Line (DSL) provider. It can also be referred as Office area network(OAN).
Campus network
A campus network is a computer network made up of an interconnection of local area networks (LANs) within a limited geographical area. The networking equipments (switches, routers) and transmission media (optical fiber, copper plant, Cat5 cabling etc.) are almost entirely owned (by the campus tenant / owner: an enterprise, university, government etc.).
In the case of a university campus-based campus network, the network is likely to link a variety of campus buildings including; academic departments, the university library and student residence halls.
Wide area network
A wide area network (WAN) is a computer network that covers a large geographic area such as a city, country, or spans even intercontinental distances, using a communications channel that combines many types of media such as telephone lines, cables, and air waves. A WAN often uses transmission facilities provided by common carriers, such as telephone companies. WAN technologies generally function at the lower three layers of the OSI reference model: the physical layer, the data link layer, and the network layer.
Global area network
A global area network (GAN) is a network used for supporting mobile communications across an arbitrary number of wireless LANs, satellite coverage areas, etc. The key challenge in mobile communications is handing off the user communications from one local coverage area to the next. In IEEE Project 802, this involves a succession of terrestrial WIRELESS local area networks (WLAN).
Enterprise private network
An enterprise private network is a network build by an enterprise to interconnect various company sites, e.g., production sites, head offices, remote offices, shops, in order to share computer resources.


Sample EPN made of Frame relay WAN connections and dialup remote access.
Virtual private network


Sample VPN used to interconnect 3 office and Remote users
A virtual private network (VPN) is a computer network in which some of the links between nodes are carried by open connections or virtual circuits in some larger network (e.g., the Internet) instead of by physical wires. The data link layer protocols of the virtual network are said to be tunneled through the larger network when this is the case. One common application is secure communications through the public Internet, but a VPN need not have explicit security features, such as authentication or content encryption. VPNs, for example, can be used to separate the traffic of different user communities over an underlying network with strong security features.
A VPN may have best-effort performance, or may have a defined service level agreement (SLA) between the VPN customer and the VPN service provider. Generally, a VPN has a topology more complex than point-to-point.
Internetwork
An Internetwork is the connection of two or more private computer networks via a common routing technology (OSI Layer 3) using routers. The Internet is an aggregation of many internetworks, hence its name was shortened to Internet.
Internet
The Internet is a global system of interconnected governmental, academic, corporate, public, and private computer networks. It is based on the networking technologies of the Internet Protocol Suite. It is the successor of the Advanced Research Projects Agency Network (ARPANET) developed by DARPA of the United States Department of Defense. The Internet is also the communications backbone underlying the World Wide Web (WWW).
Participants in the Internet use a diverse array of methods of several hundred documented, and often standardized, protocols compatible with the Internet Protocol Suite and an addressing system (IP Addresses) administered by the Internet Assigned Numbers Authority and address registries. Service providers and large enterprises exchange information about the reachability of their address spaces through the Border Gateway Protocol (BGP), forming a redundant worldwide mesh of transmission paths.
Intranets and extranets
Intranets and extranets are parts or extensions of a computer network, usually a local area network.
An intranet is a set of networks, using the Internet Protocol and IP-based tools such as web browsers and file transfer applications, that is under the control of a single administrative entity. That administrative entity closes the intranet to all but specific, authorized users. Most commonly, an intranet is the internal network of an organization. A large intranet will typically have at least one web server to provide users with organizational information.
An extranet is a network that is limited in scope to a single organization or entity and also has limited connections to the networks of one or more other usually, but not necessarily, trusted organizations or entities—a company's customers may be given access to some part of its intranet—while at the same time the customers may not be considered trusted from a security standpoint. Technically, an extranet may also be categorized as a CAN, MAN, WAN, or other type of network, although an extranet cannot consist of a single LAN; it must have at least one connection with an external network.
Overlay network
An overlay network is a virtual computer network that is built on top of another network. Nodes in the overlay are connected by virtual or logical links, each of which corresponds to a path, perhaps through many physical links, in the underlying network.


A sample overlay network: IP over SONET over Optical
For example, many peer-to-peer networks are overlay networks because they are organized as nodes of a virtual system of links run on top of the Internet. The Internet was initially built as an overlay on the telephone network .
Overlay networks have been around since the invention of networking when computer systems were connected over telephone lines using modem, before any data network existed.
Nowadays the Internet is the basis for many overlaid networks that can be constructed to permit routing of messages to destinations not specified by an IP address. For example, distributed hash tables can be used to route messages to a node having a specific logical address, whose IP address is not known in advance.
Overlay networks have also been proposed as a way to improve Internet routing, such as through quality of service guarantees to achieve higher-quality streaming media. Previous proposals such as IntServ, DiffServ, and IP Multicast have not seen wide acceptance largely because they require modification of all routers in the network.[citation needed] On the other hand, an overlay network can be incrementally deployed on end-hosts running the overlay protocol software, without cooperation from Internet service providers. The overlay has no control over how packets are routed in the underlying network between two overlay nodes, but it can control, for example, the sequence of overlay nodes a message traverses before reaching its destination.
For example, Akamai Technologies manages an overlay network that provides reliable, efficient content delivery (a kind of multicast). Academic research includes End System Multicast and Overcast for multicast; RON (Resilient Overlay Network) for resilient routing; and OverQoS for quality of service guarantees, among others.
Basic hardware components
All networks are made up of basic hardware building blocks to interconnect network nodes, such as Network Interface Cards (NICs), Bridges, Hubs, Switches, and Routers. In addition, some method of connecting these building blocks is required, usually in the form of galvanic cable (most commonly Category 5 cable). Less common are microwave links (as in IEEE 802.12) or optical cable ("optical fiber").
Network interface cards
A network card, network adapter, or NIC (network interface card) is a piece of computer hardware designed to allow computers to communicate over a computer network. It provides physical access to a networking medium and often provides a low-level addressing system through the use of MAC addresses.
Repeaters
A repeater is an electronic device that receives a signal, cleans it of unnecessary noise, regenerates it, and retransmits it at a higher power level, or to the other side of an obstruction, so that the signal can cover longer distances without degradation. In most twisted pair Ethernet configurations, repeaters are required for cable that runs longer than 100 meters. Repeaters work on the Physical Layer of the OSI model.
Hubs
A network hub contains multiple ports. When a packet arrives at one port, it is copied unmodified to all ports of the hub for transmission. The destination address in the frame is not changed to a broadcast address.It works on the Physical Layer of the OSI model.
Bridges
A network bridge connects multiple network segments at the data link layer (layer 2) of the OSI model. Bridges do send broadcasts to all ports except the one on which the broadcast was received. However, bridges do not promiscuously copy traffic to all ports, as hubs do, but learn which MAC addresses are reachable through specific ports. Once the bridge associates a port and an address, it will send traffic for that address to that port only.
Bridges learn the association of ports and addresses by examining the source address of frames that it sees on various ports. Once a frame arrives through a port, its source address is stored and the bridge assumes that MAC address is associated with that port. The first time that a previously unknown destination address is seen, the bridge will forward the frame to all ports other than the one on which the frame arrived.
Bridges come in three basic types:
• Local bridges: Directly connect local area networks (LANs)
• Remote bridges: Can be used to create a wide area network (WAN) link between LANs. Remote bridges, where the connecting link is slower than the end networks, largely have been replaced with routers.
• Wireless bridges: Can be used to join LANs or connect remote stations to LANs.
Switches
A network switch is a device that forwards and filters OSI layer 2 datagrams (chunk of data communication) between ports (connected cables) based on the MAC addresses in the packets is distinct from a hub in that it only forwards the frames to the ports involved in the communication rather than all ports connected. A switch breaks the collision domain but represents itself as a broadcast domain. Switches make forwarding decisions of frames on the basis of MAC addresses. A switch normally has numerous ports, facilitating a star topology for devices, and cascading additional switches.[9] Some switches are capable of routing based on Layer 3 addressing or additional logical levels; these are called multi-layer switches. The term switch is used loosely in marketing to encompass devices including routers and bridges, as well as devices that may distribute traffic on load or by application content (e.g., a Web URL identifier).
Routers
A router is an internetworking device that forwards packets between networks by processing information found in the datagram or packet (Internet protocol information from Layer 3 of the OSI Model). In many situations, this information is processed in conjunction with the routing table (also known as forwarding table). Routers use routing tables to determine what interface to forward packets (this can include the "null" also known as the "black hole" interface because data can go into it, however, no further processing is done for said data).