CompTIA Network + 1.2 (Network Topologies and types)

Mesh Topology

(Wireless Networks) Devices are connected with many redundant interconnections between network nodes. Two types: Partially Meshed and Fully Meshed

Fully Meshed Topology

A mesh network where every node is directly connected to every other node.

Bus Topology

A network layout in which there is one main trunk, or backbone (formed by a coaxial cable), that all the various computers and network devices are connected to.

Metropolitan area network (MAN)

A network that spans a metropolitan area, usually a city and its major suburbs. Its geographic scope falls between a WAN and a LAN

Wireless Local Area Network (WLAN)

Links two or more devices over a short distance using a wireless distribution method, usually providing a connection through an access point for Internet access.

Metro-E (Metro Ethernet)

MAN - connects a contained regional area; the sites are connected with ethernet.

vSwitch

Move the physical switch and its functionality into the virtual world. Easy deployment from hypervisor. Can be automated.

Personal Area Network (PAN)

provides communication for devices owned by a single user that work over a short distance Example: Bluetooth

Star (Hub and Spoke) Topology

A LAN configuration in which a central node controls all message traffic.

Ring Topology

A LAN configuration in which all nodes are connected in a closed-loop

Digital Subscriber Line (DSL)

(or ASDL - Asymmetric Digital Subscriber Line) provides high-speed digital data transmission over standard telephone lines using broadband modem technology, allowing both Internet and telephone services to work over the same phone lines. There's usually a 10,000 limitation distance to the central office (CO.)

Smartjack

- Network interface unit (NIU) -- The device that determines the demarc -- Network Interface Device, Telephone Network Interface - Smartjack -- More than just a simple interface -- Can be a circuit card in a chassis - Built-in diagnostics -- Loopback tests - Alarm indicators -- Configuration, status

Bus Topology Disadvantages

-If there a problem with the central cable the whole network stops working. -There is a maximum length for how long the central cable can be and therefore a limit on how many computers, printers etc can be connected to the network.

client/server network

A network that uses centrally administered computers, known as servers, to enable resource sharing for and to facilitate communication between the other computers on the network. Example: Web browsers and web servers on the internet

peer-to-peer network

A network without a central server. Attached devices act as both "client" and "server." Example: In torrent, all the computers are connected to each other on the internet. One computer can upload any file in the network and other computers start downloading the files. Also, every computer can upload parts of the file if that computer has already downloaded some chunks of the file. Another example is sharing access to a printer.

leased line

A serial communications circuit between two points, provided by some service provider, typically a telephone company (telco). Because the telco does not sell a physical cable between the two endpoints, instead charging a monthly fee for the ability to send bits between the two sites, the service is considered to be a leased service.

Ring topology disadvantages

Adding/removing nodes disables the network Low Redundancy: Failure of one node brings down the network Problems in data transmission can be a hard to find Can take longer to send data if on wrong side of the ring Security: Everyone can see your message, better encrypt it! *Still used in "MANs" to an extent*

Fiber

Allows for high-speed data communication by using light. They're marked by higher installation costs because the equipment is costly and more difficult to repair. Allows communication over long distances. WAN providers and ISP very commonly use Fiber because it supports very high data rates.

Multipoint Generic Routing Encapsulation (mGRE)

Allows for the creation of network connections dynamically. These dynamic connections are only created when they're needed. Used extensively for a dynamic multipoint virtual private network (DMVPN.) \ A dynamic mesh that builds data tunnels on-demand and terminates them when they're not needed.

Network Function Virtualization (NFV)

Alternately referred to as virtual network function. The objective of NFV is to decouple functions, such as firewall management, intrusion detection, network address translation, and name service resolution, away from specific hardware implementation and move them into software solutions. NFV's focus is to optimize distinct network services.

Campus Area Network (CAN)

An interconnection of networks located in nearby buildings (for example, buildings on a college campus).

Hybrid Topology

Any form of networking technology that combines a physical topology with a signaling topology. (Ex. Star-ring and Star-bus)

Partially Meshed Topology

At least two machines have redundant connections.

Metro-optical

Combine the power of Ethernet and optical technologies across a metro-/wide-area network (MAN/WAN) to deliver low cost, scalable and secure bandwidth. Improve your data application performance

Local Area Network (LAN)

Connects a group of computers in close proximity, such as in an office building, school, or home. Usually an ethernet network.

Copper

Copper cables have been installed extensively, are relatively inexpensive, and are easy to maintain. However, bandwidth availability is limited because...physics. Very common on WANs and DSL. Copper is often combined with fiber to construct a network--copper on the local loop and fiber in a companies broader cable infrastructure.

Mesh topology advantages

Data can be going between different nodes at the same time. If a node goes down it doesn't destroy the network. Fault Tolerance/Built-in redundancy

Multiprotocol Label Switching (MPLS)

Eases routing decisions by labeling every packet transmitted through the WAN; this allows any transport medium (frames, ip packets) with any protocol inside. Labels are "pushed" onto packets as they enter the MPLS cloud and "popped" off as they leave. Forwarding decisions are made based on this labeling.

MPLS vs IP routing

In typical IP routing, a packet's forwarding route is computed at each individual router, as opposed to being predetermined by MPLS labeling.

Cable Broadband

Instead of using the existing telephone lines, special cabling has been laid which allows signals to travel at speeds up to 1000Mb. It allows transmission across multiple different frequencies and traffic types.

NAS vs SAN

NAS has its own OS not many upgrades, and not much performance. Has a single point of failure because a NAS is a centralized storage method. Less expensive SAN A dedicated network used for data storage. More fault tolerant because it's less centralized. A computer recognizes SANs as a locally attached hard drive. Much more scalable and not affected by network traffic. More expensive because most SANs use fiber optic cabling to ensure fast data speeds, as well as other hardware such as switches as opposed to a central box.

vNIC (Virtual Network Interface Card)

Since a virtual machine needs a network interface: A vNIC is configured and connected through the hypervisor. The digitization allows for additional functionality such as VLAN and multiple interfaces.

Wide Area Network (WAN)

Spans a large geographic area such as a state, province, or country. Example: the internet

Virtual Machine

The apparent machine that the operating system presents to the user, is achieved by hiding the complexities of the hardware behind layers of operating system software. Can be configured so as to have multiple virtual machines running on one computer.

Demarcation Point

The point of division between a telecommunications service carrier's network and a building's internal network. Where LAN meets WAN. (Might be as simple as a RJ-45 connector) The location of the Demarc is important because it signifies where a company's responsibilities end and ISP's responsibilities begin.

Customer Premises Equipment (CPE)

The primary distribution box and customer-owned/managed equipment that exists on the customer side of the demarc. Where one connects to a network to do trouble shooting.

Hypervisor

Virtual Machine Manager - Software that enables a single computer to run multiple operating systems simultaneously. Hardware management for virtual systems - CPU - Networking -Security

SD-WAN (software-defined wide area network)

WAN can be defined however needed. Devices can communicate directly to the cloud instead of hopping through a data center.

WLAN vs Mesh

WLAN uses radio frequency technology to replace the old localized network of twisted copper wires with electromagnetic waves, and communication in thin-air. Although also composed of a router and a client, several nodes constitute a backbone network and are connected to a wired internet network, which is responsible for providing a multi-hop wireless internet connection to the client. Wireless mesh networks remove the cabling requirements between nodes, but still have the redundancy and rerouting capabilities provided by distributed networks.

Wireless Local Area Network (WLAN)

a computer network in a limited geographical area that uses wireless transmission for communication

Storage Area Network (SAN)

a dedicated high-speed network consisting of both hardware and software used to connect and manage shared storage devices, such as disk arrays, tape libraries, and optical storage devices

file-based data storage

a hierarchical storage methodology used to organize and store data. In other words, data is stored in files, the files are organized in folders and the folders are organized under a hierarchy of directories and subdirectories.

SD-WAN Advantages

businesses can connect multiple locations via the cloud vs using miles of cables to connect locations. This reduces latency and enables businesses to quickly scale out their virtualized WAN as they add new locations and quickly push out network updates across all locations via a cloud-based portal.

Network Attached Storage (NAS)

essentially a network-connected computer dedicated to providing file-based data storage services to other network devices.

Star Topology Advantages

has built-in redundancy and fault tolerance, much more so than Ring and Bus.

Satellite networking

• Non-terrestrial communication Hardware requirements make it expensive. Can be used to provide internet access for areas in which cable instillation isn't feasible. • 15 Mbit/s down, 2 Mbit/s up • High latency • High frequencies - 2 GHz