Friday, 9 May 2014

ATM NETWORK TECHNOLOGY

ATM (Asynchronous Transfer Mode) is a high speed network technology that has become the standardized solution for the telecommunication industry, teleconferencing, videoconferencing, telemedicine, HDTV, distance learning and where high speed data transfer is required.   ATM technology integrates voice, data and video at the same time. ATM uses fixed size packets called cells of 55 bytes in length. ATM network is a high speed circuit switched network that is capable of transferring one million signals using ATM protocol. ATM is a connection oriented technology in which logical connections are established for the data communication. ATM is implemented in the WAN and telecommunication sectors. Small data cells are used for communication and ATM is designed for high speed and high traffic networks. ATM cells allow voice, data and video transfer at the same time. ATM operates on the data link layer of the OSI model and it uses UTP/STP, fiber optic or air as a communication medium.

ATM CELL BASE
It is a small unit of 55 bytes fixed length and it contains the users and signaling information in it. It has a header with very limited functionality to reduce the internal buffer and to provide the high speed transfer. ATM cell identify the cells that belongs to the same virtual channels and perform easy routing.
  
ATM SWITCHING
Various switching technologies have been developed in the past to provide the high speed data transfer and secure communication. ATM switching technology provides high speed data transfer due to the connection oriented technology. ATM switching technology uses the predefined routing table so guarantees the fast data communication.
ATM DEVICES
ATM basically uses two types of devices such as ATM switch and end systems. The function of the switch is to handle the transmission of the cells throughout the network. Switches accept the incoming cells from the ATM end station or another ATM switch. On the other hand, ATM end systems contain the ATM adaptors.
ATM CONNECTIONS
ATM supports two types of connections point to point and point to multi point connections. In the point to point connections, two end systems are connected bi directionally or uni directionally. The point to multi point system connects one source to the number of destinations in uni directional. The source sends the information and switch replicates it to the destinations. Unidirectional network connects two switches. A typical ATM network consists of a set of the switches interconnected by point to point links. Switch support two types of interfaces user network and network node interface. Asynchronous transfer mode technology is designed for the reliability, performance, utilization and QOS and it creates fixed channels and routes when data travels between two points. There are four types of the choice when purchasing a connection.
Constant Bit Rate: It specifies fixed size rate and data is transferred in a steady form. Variable bit rate.
Variable Bit Rate: It provides specified throughput and it is best for videoconferencing.
Available bit rate. It provides guaranteed minimum capacity but high rate is also possible when the network is free.
Unspecified bit rate. It does not provide any fixed throughput level and it is best for the file transfer where delay can occurred.
ATM ADVANTAGES
It provides fixed bandwidth and simple routing is possible due to the connection oriented technology. High bandwidth utilization can be possible so it is the best solution for the telecommunication sector, videoconferencing and QOS. There are some of the disadvantages of this technology such as high cost, cell loss due to the high congestion in the network.

What is WAN Optimization ??

How to Optimize WAN
Networks play an important role in the businesses and if the network is slow so is the business. For improving the performance there are different techniques and products are on the rise such as route control products, content delivery networks, load balancing technology, multicasting and caching.
The other techniques and methods that are involved in improving the performance of the wide area network are CIFS proxy, HTTPS proxy, media multicasting, bandwidth management, web casting and WAFS.  Deployment of the wide area network optimization appliances at the data center and the branch sites boosts the network and distributed application performance with the minimum efforts.
Improving applications performance over the networks has become the ultimate goal of the organizations.  Varying network types and applications require different solutions.  WAN accelerators and WAFS optimize the data that travel over the longer distance.  Traffic over the wire is optimized through streaming, compression, prioritization, local and centralized caching and other methods.

Optimization Techniques
The optimization software and hardware use the following techniques to boost the performance of a network.
  • Staging data on the local cache
  • Compressing and prioritizing data
  • Streamlining chatting protocols.
Vendors
The following vendors provide the WAN optimization products and appliances.
  • Cisco
  • Juniper
  • Blue Coat
  • F5 Networks
  • Silver Peak
  • River Bed
  • InMage
  • Peribit
Most of the products provided by these vendors are the hardware based and some are the combination of hardware and software.
Juniper offers the following Networks Application Acceleration Platforms.
  • WX Platforms
This platform is used to increase the application performance, application and data prioritization, WAN capacity and this platform delivers compressed output that travels at the speed 64 Kbps to 155 Mbps.
  • WXC Platforms
WXC Platforms holds the on-board hard drives that are used to store the repeated data and that ultimately increase the WAN capacity by 100 folds.  WXC Platforms support the disk capacity from 40 GB to 3 TB and WAN links from 128 Kbps to 155 Mbps.
  • WX CMS
WX CMS platform is used to manage multiple WX platforms and WXC platforms from one central location.  There are easy monitoring and configuration tools in this platform.  The main feature of the WX CMS is the application performance, WAN utilization, bandwidth allocation and QOS.

What is WAN ?

WAN (Wide Area Network) is a data communication network that covers a broad geographic area.  The term WAN applies to the broader telecommunication infrastructure.  Router is the main communication device in the WAN networks.

How WAN Works?
A WAN is a network of interconnected devices such as router, switches, modems, wireless devices, DSL services, frame relay devices, access servers, ISDN terminal adapters, DSU devices and WAN switches.  The most common WAN circuits are packet switching, circuit switching and point to point communication.  In WAN routing the routing table contains the IP addresses of the source and destination devices.  On the basis of the routing table, the router chooses the best possible shortest path for the packets.
A point to point link is also known as a leased line and which provides the communication between two remote locations through a carrier network such as Telecommunication Company.  In circuit switching a carrier network is involved in establishing, maintaining and terminating communication session. In packet switching, the communication devices share point to point link to transfer packets from the source and destination. Dial-up services provide cost effective solutions for WAN connectivity.
WAN Technologies
The WAN technologies operate at the lowest level of the OSI layer model.
ATM
ATM or Asynchronous Transfer Mode is a high bandwidth and high speed wide area network technology that operates at the speed of 155Mbps.  ATM is also called cell relay and it supports multiple data types such as data, voice, video etc.  ATM uses fixed sized packets for data communication that are also known as packets.
Dial UP
Dial up WAN provide the cost effective communication solutions.  Dial up demand and dial up backup is the two WAN dial up services.  In a DDR, a router dynamically initiates a call on a switched circuit when it requires sending data.
In dial backup, switched circuit is used to provide the backup services for other types of networks such as PPP or packet switching.
X.25
X.25 is a data communication protocol in the packet switched networks.  X.25 allows computers at the remote locations to communicate with each other through a centralized computer.
Frame Relay
Frame relay is a very high speed and high performance WAN protocol.  Frame relay operates at the physical and data link layers of the OSI model.  Frame relay is a networking method that is designed for the data transmission between LAN and WAN.
ISDN Lines
Integrated Services Digital Network is a WAN communication method over the regular telephone lines.
Circuit Switching
In WAN, when a router has data for the remote site the switched circuit is initiated.  When two remote networks communicate and authenticate then the communication starts.  ISDN is the best example of the circuit switching network.
Packet Switching
In packet switching the common carrier resources are shared between the remote networks.  ATM, Frame Relay and X.25 are the examples of the packet switched networks.  In this technology, the network has connections into the carrier networks and some portion of the carrier network is shared.
CSU/DSU
Channel Circuit Unit/Digital Circuit Unit is a device that is used to connect a router with the digital circuit like T1.
WAN Routing
WAN routing is a technique of forwarding the packets towards the destination based on the IP address of the next hop.