OSPF (Open Shortest Path First)

ospf-routing-protocol

What is OSPF? OSPF (Open Shortest Path First) is an open source dynamic routing protocol based on Link State Routing Algorithm for IP Networks. It has a Protocol Type/Class which is based on IP/Link-State. OSPF uses an Algorithm called SPF (Dijkstra) to determine the shortest path. It is an IGP (Interior Gateway Protocol) Type of protocol and it uses Cost (Bandwidth) as its metric value. OSPF has 5 no. of packet types and has an Admin Distance of 110. It has a Reference Bandwidth of 108 and has a defined Standard of IETF RFC2328 (OSPFv2), IETF RFC2740 (OSPFv3/IPv6) for OSPF Read More …

Static and Default Routing

static-default-routing

Static and Default Routing are two types of routing in which the path selection is controlled manually by a network administrator. STATIC ROUTING “It is a type of fixed routing in which path selection and routing is controlled manually by a network admin”. Static routes have Admin Distance (AD) of 1. Path selection  and routing is manually controlled by a network administrator in static routing. Static routes are always preferred over Dynamic routing protocols like OSPF/RIP/BGP. They consume less resources and less bandwidth intensive. Static Routes are not fault tolerant (paths are always fixed). Therefore, they are not practical for Read More …

Bit Error Rate & BERT Meter (part2)

Bit Error rate control & Bit Error testing (BERT) is crucial to network performance especially for Ethernet, SDH, DWDM and OTN Networks that are based on Optical transmission.   What is a BERT Meter (BER Tester)? A BERT Meter is an electronic device that is used to measure the Bit Error Rate. There are many equipment vendors that manufacturer that sell BER Testers. Some of the popular companies are JDSU, Anritsu and EXFO. However, their prices & features vary a lot. Below is one of the famous BERT Meter model as an example (courtesy JDSU).       How to Read More …

Bit Error Rate & BERT Meter (part1)

Bit Error Rate & BERT

Performance of the transmission system is of crucial importance to communication quality of the whole communication network. Good performance can be achieved through proper control over Bit Error Rate & BERT. The major factors affecting the performance of SDH transmission network includes bit error, jitter and wander. So, what are the Bit Errors? Why are they so important to control? Do the Bit errors affect my network performance? These are some of the questions that every network engineer and optical transmission engineer must know. Let’s dissect these questions & their answers one by one. “Bit Error is the amount of Read More …

IP Address & its Types

IP address types ipv4 ipv6

“IP address is a unique number which is used to identify network devices in computer networks”. An IP address mainly serves two functions: host or network interface identification and location addressing. It is a logical numeric address that is assigned to every single computer, printer, switch, router or any other device that is part of a TCP/IP based network. The IP exists in every network, even only a pair of computers or a network of a large enterprise. Each computer, without exceptions, has its own unique address, if there is a connection to the network. Each of the computers in Read More …

Application Layer of OSI Model (Layer-7)

Application Layer is the highest layer in seven layer OSI Model. It is responsible for End user Network Applications Management. This is the layer where real traffic data is generated in most of the cases. For example, this could be a web request generated from HTTP protocol or a command from telnet protocol. OSI Model divides the network communication processes into seven layers in order to simplify it. Each layer performs specific functions to support the layers above it. The seven Layer model starts from Physical Layer & goes till Application Layer on the top, as below in figure: Functions/Duties Read More …

Presentation Layer of OSI Model (Layer-6)

Presentation Layer of OSI Model

Presentation Layer is responsible for representation & formatting of data for session Layer in encapsulation process. It is the 6th Layer in the seven layer OSI Model after Session Layer. Presentation layer serves like a translator & takes care that the data is sent in such a way that the receiver will understand the information or data and will be able to use the data. OSI Model divides the network communication processes into seven layers in order to simplify it. Each layer performs specific functions to support the layers above it. This seven Layer model starts from Physical till Application Read More …

Session Layer of OSI Model (Layer-5)

Session Layer of OSI Model

Session layer of OSI Model is designed to allow devices to establish and manage sessions so that multiple channels could be established between same terminals and hosts. Session Layer is the fifth layer in the 7-Layer OSI Model after Transport Layer. Session Layer is also called as ‘Port Layer’. The main function of Session Layer is to establish, maintain and synchronize the interaction between communicating systems and hosts like computers and servers. It allows information of different streams, originating from different sources, to be properly combined or synchronized. OSI Model divides the network communication processes into seven layers in order Read More …

Transport Layer of OSI Model (Layer-4)

Transport Layer of OSI Model

Transport Layer is the fourth layer in 7 Layer OSI Model after Network Layer. Similar to Layer-2 and Layer-3, this layer also performs addressing & multiplexing but in different domain through TCP and UDP. OSI Model divides the network communication processes into seven layers in order to simplify it. Each layer performs specific functions to support the layers above it. The seven Layer model starts from Physical till Application Layer & Transport layer is in the middle. The core concept behind Transport layer is the “support of Multitasking”. It allows same computer, browser & internet connection to work on multiple Read More …

Network Layer of OSI Model (Layer-3)

Network Layer of OSI Model

Network Layer is the 3rd layer in 7-Layer OSI Model after Data Link Layer. This is the place where most Routing and network stuff resides. It controls the Logical boundaries of Network. Network Layer controls the operation in networking at routing layer. The main aim of this layer is to deliver packets from source to destination across multiple links or networks. If two computers or host systems are connected on the same link, then there is no need for a network layer. Each layer in OSI Model performs specific functions to support the layers above it. This 7x Layer model Read More …