What is Topology?Network Topology is the way network links and nodes are connected with each other. The physical signal transmission medium is referred to as network topology. On the other hand, "logical network topology" refers to how the data flows through a network among the connected devices, regardless of their physical link.In this article, we will compare and contrast the different features of two network topologies − Ring Topology and Mesh Topology. Read through this article to find out how Ring Topology differs from Mesh Topology.What is Mesh Topology?A mesh network is a sort of local network structure that is ... Read More

Nmap is a free open source tool, employed to discover hosts and services on a computer network by sending packets and analyzing the retrieved responses. Nmap offers some features for probing computer networks, including host discovery and service and operating system detection.Nmap can provide further information on targets, including reverse DNS names, device types, and MAC addresses.Host discovery – Identifying hosts on a network. For example, listing the hosts that respond to TCP and/or ICMP requests or have a particular port open.Port scanning – Enumerating the open ports on target hosts.OS detection – Determining the operating system and hardware characteristics ... Read More

Orthogonal frequency division multiple access (OFDMA) is a multi-user version of digital data modulation scheme OFDM (orthogonal frequency division multiplexing). In OFDM, a single stream of data is divided into several separate sub-streams for transmission via multiple channels. OFDM uses the principle of frequency division multiplexing (FDM), where the available bandwidth is divided into a set of sub-streams having separate frequency bands.In OFDMA, multiple access is achieved by assignment of different subsets of subcarriers to individual stations. This permits transmission to go on simultaneously at lower data rate from several stations.The stations assigned to a given subcarrier alternate between sending ... Read More

The IEEE 802.16 is a set of standards that lays down the specifications for wireless broadband technology. It has been commercialized as Worldwide Interoperability for Microwave Access (WiMAX) that is responsible for delivery of last mile wireless broadband access. It lays down the standards for both physical layer as well as medium access control (MAC) layer for WiMAX.Physical Layer Features of WiMAXThere are two popular services of the physical layer −Fixed WiMAX.Mobile WiMAX.WiMAX initially provided data rates of 30 – 40 Mbps. The updated version that came in 2011 provides up to 1 Gbps data rates for fixed stations.It operates ... Read More

The IEEE 802.16 set of standards lays down the specifications for wireless broadband technology. It has been commercialized as Worldwide Interoperability for Microwave Access (WiMAX) and is responsible for delivery of last mile wireless broadband access.The IEEE 802.16 lays down the standards for both physical layer as well as medium access control (MAC) layer for WiMAX. The general structure of the IEEE protocol stack is shown as below −As shown in the diagram, IEEE 802.16 lays down the standards for physical layer and data link layer.Physical Layer − The two popular services of the physical layer are fixed WiMAX and ... Read More

The IEEE 802.16 is a set of standards that lays down the specifications for wireless broadband technology. It has been commercialized as Worldwide Interoperability for Microwave Access (WiMAX) that is responsible for delivery of last mile wireless broadband access.The IEEE 802.16 architecture lays down the standards for both physical layer as well as medium access control (MAC) layer for WiMAX. It initially provided data rates of 30 – 40 Mbps. The updated version that came in 2011 provides up to 1 Gbps data rates for fixed stations. It operates in the frequency band of 2 GHz to 11 GHz. The ... Read More

The 802.16 is a set of standards defined by IEEE (Institute of Electrical and Electronics Engineers) that lays down the specifications for wireless broadband technology. It has been commercialized as Worldwide Interoperability for Microwave Access (WiMAX) that is responsible for delivery of last mile wireless broadband access.The IEEE 802.16 lays down the standards for both physical layer as well as medium access control (MAC) layer for WiMAX. It initially provided data rates of 30 – 40 Mbps. The updated version that came in 2011 provides up to 1 Gbps data rates for fixed stations. It operates in the frequency band ... Read More

Preemptive Scheduling is a CPU scheduling technique that works by dividing time slots of CPU to a given process. The time slot given might be able to complete the whole process or might not be able to it. When the burst time of the process is greater than CPU cycle, it is placed back into the ready queue and will execute in the next chance. This scheduling is used when the process switch to ready state.Algorithms that are backed by preemptive Scheduling are round-robin (RR), priority, SRTF (shortest remaining time first).Non-preemptive Scheduling is a CPU scheduling technique the process takes ... Read More

There are various application programs that we can use to access the resources of a remote machine. Telnet and SSH are the primary client server application programs that use remote terminal service which allows a user at one site to interact with a remote timesharing system at another site as if the user’s keyboard and a display is connected directly to the remote machine. Telnet and SSH both are Layer7 application layer protocols and both use TCP (Transmission Control Protocol) at the transport layer. In this article, we will discuss the important differences between SSH and Telnet. But before going ... Read More

QoS traffic scheduling is a scheduling methodology of network traffic based upon QoS (Quality of Service). Here, the frames or packets are mapped to internal forwarding queues based on its QoS information, which are then services according to a queuing scheme.Typically, multiple queues are present each with different priority levels. The scheduler decides the type of treatment to be given to the traffic in each queue. When traffic is available, the scheduler maps it to the appropriate queue. For example, video and voice traffic are kept is queued with higher priority than background traffic.Notable QoS Traffic Scheduling MethodsWeighted Round Robin ... Read More