NETWORK TOPOLOGIES

In networking, the term topology refers to the layout of connected devices on a network.
Network topologies are categorized into the following basic types:
bus
ring
star
tree
mesh

BUS
More complex networks can be built as hybrids of two or more of the above basic topologies.

Bus networks (not to be confused with the system bus of a computer) use a common backbone to connect all devices. A single cable, the backbone functions as a shared communication medium, those devices attach or tap into with an interface connector. A device wanting to communicate with another device on the network sends a broadcast message onto the wire that all other devices see, but only the intended recipient actually accepts and processes the message.

Bus consists of a single linear cable called a trunk.
Data is sent to all computers on the trunk. Each computer examines EVERY packet on the wire to determine who the packet is for and accepts only messages addressed to them.

Bus is a passive topology.
Performance degrades as more computers are added to the bus.
Signal bounce is eliminated by a terminator at each end of the bus.
Barrel connectors can be used to lengthen cable.
Usually uses Thin net or Thicket
both of these require 50 ohm terminator
good for a temporary, small (fewer than 10 people) network
But it’s difficult to isolate malfunctions and if the backbone goes down, the entire network goes down.
Repeaters can be used to regenerate signals.

Ethernet bus topologies are relatively easy to install and don't require much cabling compared to the alternatives. 10Base-2 ("ThinNet") and 10Base-5 ("ThickNet") both were popular Ethernet cabling options years ago. However, bus networks work best with a limited number of devices. If more than a few dozen computers are added to a bus, performance problems will likely result. In addition, if the backbone cable fails, the entire network effectively becomes unusable.

Ring

In a ring network, every device has exactly two neighbors for communication purposes. All messages travel through a ring in the same direction (effectively either "clockwise" or "counterclockwise"). A failure in any cable or device breaks the loop and can take down the entire network.

To implement a ring network, one typically uses FDDI, Sonet , or Token Ring tech Ring Topology

Computers are connected on a single circle of cable.
usually seen in a Token Ring or FDDI (fiber optic) network
Each computer acts as a repeater and keeps the signal strong => no need for repeaters on a ring topology
No termination required => because its a ring
Token passing is used in Token Ring networks. The token is passed from one computer to the next, only the computer with the token can transmit. The receiving computer strips the data from the token and sends the token back to the sending computer with an acknowledgment. After verification, the token is regenerated.
relatively easy to install, requiring ;minimal hardware

Star

Many home networks use the star topology. A star network features a central connection point called a "hub" that may be an actual hub or a switch. Devices typically connect to the hub with Unshielded Twisted Pair (UTP) Ethernet.

Compared to the bus topology, a star network generally requires more cable, but a failure in any star network cable will only take down one computer's network access and not the entire LAN. (If the hub fails, however, the entire network also fails.)
Computers are connected by cable segments to a centralized hub.

Signal travels through the hub to all other computers.
Requires more cable.
If hub goes down, entire network goes down.
If a computer goes down, the network functions normally.
most scalable and reconfigurable of all topologies

Mesh
The mesh topology connects each computer on the network to the others
Meshes use a significantly larger amount of network cabling than do the other network topologies, which makes it more expensive.
The mesh topology is highly fault tolerant.
Every computer has multiple possible connection paths to the other com-putters on the network, so a single cable break will not stop network communications between any two computers.

Star Bus Topology
Several star topologies linked with a linear bus.
No single computer can take the whole network down. If a single hub fails, only the computers and hubs connected to that hub are affected.

Star Ring Topology
Also known as star wired ring because the hub itself is wired as a ring. This means it's a physical star, but a logical ring.
This topology is popular for Token Ring networks because it is easier to implement than a physical ring, but it still provides the token passing capabilities of a physical ring inside the hub.
Just like in the ring topology, computers are given equal access to the network media

through
The passing of the token.
A single computer failure cannot stop the entire network, but if the hub fails, the ring that the hub controls also fails.

Hybrid Mesh
most important aspect is that a mesh is fault tolerant
a true mesh is expensive because of all the wire needed
Another option is to mesh only the servers that contain information that everyone has to get to. This way the servers (not all the workstations) have fault tolerance at the cabling level.

Project Management

Project management is a carefully planned and organized effort to accomplish a specific (and usually) one-time effort, for example, construct a building or implement a new computer system. Project management includes developing a project plan, which includes defining project goals and objectives, specifying tasks or how goals will be achieved, what resources are need, and associating budgets and timelines for completion. It also includes implementing the project plan, along with careful controls to stay on the "critical path", that is, to ensure the plan is being managed according to plan. Project management usually follows major phases (with various titles for these phases), including feasibility study, project planning, implementation, evaluation and support/maintenance. (Program planning is usually of a broader scope than project planning, but not always.)

Project management, is the application of knowledge, skills, tools, and techniques to describe, organize, oversee and control the various project processes.

Project Management is the ongoing process of directing and coordinating all the steps in the development of an information system. Effective project management is necessary throughout the entire systems development and implementation. The need for effective project management is most often recognized during system development.

The goal of project management is to produce an information system that is acceptable to its users and that is developed within the specified time frame and budget. The acceptability, deadline and budget criteria must all be met for a project to be considered completely successful. Failing to meet any one of these three criteria usually indicates a failure, at least in part, in project management.

According to the Project Management Institute the components of project management are organized into nine Project Management Knowledge Areas.

But perhaps project management can best be described in terms of the things that you need to do to successfully manage a project:


Project Integration Management:
Develop and manage a project plan. The processes required to ensure that elements of the project are properly coordinated. It consists of project plan development, project plan execution, and overall change control.

Project Scope Management:
Plan, define and manage project scope. The processes required to ensure that all the work required, and only the work required, is included to complete the project successfully. It consists of initiation, scope planning, scope definition, scope verification and scope change control.

Project Time Management:
Create a project schedule. The processes required to ensure the project is completed in a timely way. It consists of activity definition, activity sequencing, activity duration estimating, schedule development, and schedule control.

Project Cost Management:
Create plan resources and budget costs. The processes required to ensure the project is completed within he approved budget. It consists of resource planning, cost estimating, cost budgeting, and cost control.

Project Quality Management:
Develop a quality plan and carry out quality assurance and quality control activities. The processes required to ensure that the project satisfies the needs for which it was undertaken. It consists of quality planning, quality assurance, and quality control.

Project Human Resource Management:
Perform organizational planning, manage staff acquisitions and promote team development. The processes required to most effectively use the people involved in the project. It consists of organizational planning, staff acquisition, and team development.

Project Communications Management:
Develop a communications plan. The processes required to timely and appropriately generate, collect, disseminate, store, and ultimately dispose of project information. It consists of communications planning, information distribution, performance reporting, and administrative closure.

Project Risk Management:
Identify risks, prepare risk mitigation plans and execute contingency actions. The processes concerned with identifying, analyzing, and responding to project risk. It consists of risk identification, risk quantification, risk response development, and risk response control.

Project Procurement Management:
The processes required to acquire goods and services from outside the organization. It consists of procurement planning, solicitation planning, solicitation, source selection, contract administration, and contract closeout.

Activities of Project Manager:
A project manager is a facilitator. The ideal project manager does whatever it takes to ensure that the members of the software project team can do their work. This means working with management to ensure they provide the resources and support required as well as dealing with team issues that are negatively impacting a team's productivity. The project manager must possess a combination of skills including the ability to ask penetrating questions, identify unstated assumptions, and resolve personnel conflicts along with more systematic management skills.
The actions of a project manager should be almost unnoticeable and when a project is moving along smoothly people are sometimes tempted to question the need for a project manager. However, when you take the skilled project manager out of the mix, the project is much more likely to miss deadlines and exceed budgets.
The project manager is the one who is responsible for making decisions in such a way that risk is controlled and uncertainty minimized. Every decision made by the project manager should ideally be directly benefit the project.
On small projects, the project manager will likely deal directly with all members of the software development team. On larger projects, there is often a lead developer, lead graphic designer, lead analyst, etc. that report directly to the project manager.

Essential qualities of project manager:
a) Strong leadership ability
Leadership is getting things done through others; the project manager achieves the results through project team. He needs to inspire the project team members, needs to create a vision of the result. Project leadership requires a participative and conclusive leadership style, in which the project manager provides guidance and coaching to the project team. It also requires involvement and empowerment of the project team. He should motivate the team to achieve its objective.

b) Ability to develop people
The effective project manager has a commitment to the training and development of people working on the project. The project manager should establish an environment where people can learn from the tasks they perform and situations they experience. He should provide opportunities for learning and development by encouraging the individuals. A final way in which a project manager can develop people is by having them attend formal training sessions.

c)Excellent communication skills
Project managers must be good communicators. It’s important for the project manager to provide timely feedback to the team and customer. The project manager needs to communicate regularly with the project team, as well as with any subcontractor, the customer and their own company’s upper management. Effective and frequent communication is critical for keeping the project moving, identifying potential problems, and soliciting suggestions to improve project performance, keeping customer satisfaction and avoiding surprises.

d) Ability to handle stress
Project managers need to handle the stress that can arise from work situations. Stress is likely to be high when some critical problems arise. The project managers can improve their ability to handle stress by keeping physically fit through regular exercise and good nutrition, he can also organize stress relief activities playing outdoor games etc.

e)Good interpersonal skills
Good interpersonal depends on how good his oral and written communication. The project manager needs to establish clear expectations of the members of the project team so that everyone knows the importance their roles in the project. A project manager needs good interpersonal skills to try to influence the thinking and action of others, to deal with disagreement or divisiveness among the team members.

f)Problem-solving skills
A project manager should encourage project team to identify problems early and solve them. Team members should be asked to give suggestions to solve the problem. The project manager should then use analytical skills to evaluate the information and develop the optimal solution.
Developing skills needed to be a project manager:
Gain experience.
Seek out feed back from others.
Conduct a self-evaluation, and learn from your mistakes.
Interview project managers who have the skills you want to develop in yourself.
Participate in training programs, volunteer yourself in other work.