Monday, November 18, 2019

CSMA/CD

CSMA / CD (Multiple Access with Bus Detection with Collision Detection) helps hosts determine when packets are sent in a shared network segment and how conflicts are detected if they occur. For example, in a centralized network, two devices can send packets at the same time. This can cause a collision. CSMA / CD allows devices to "discover" the cable to ensure that another device does not transfer packets at this time. However, if two devices detect that the cable is clear and send packets at the same time, a collision may occur. In the event of a collision, packets must be re-transmitted after a random period of time.

Consider the following example:



In the previous topology we have a network of axes. Host A tries to communicate with Host B. Host "discovers" the cable and decides to send packets. But at the same time, Host C sends its packets to Host D and the collision occurs. Transmitters (Host A and Host C) detect collision and resend the packet after a random period of time.

Monday, November 4, 2019

EIGRP Reliable Transport Protocol (RTP)

EIGRP does not send messages with UDP or TCP; instead, a Cisco protocol called Trusted Transport Protocol (RTP) is used to communicate between routers that speak EIGRP. As the name implies, reliability is an essential feature of this protocol and is designed to allow rapid delivery of updates and monitoring of data reception.




Five different packets types are used by EIGRP:

Update: Contains route information. When routing updates are sent in response to chassis or metric changes, reliable multicasts are used. If only one router needs to be updated, for example, when a new neighbor is detected, mono broadcasts are used.

Query: A specific routing request always uses the trusted multicast method. Routers send queries when they realize they have lost their way to a particular network and are looking for alternative routes.

Reply: Send a response to a query through the unicast method. Responses may include a specific route to the destination or declare that there is no known route.

Hello:I used to discover EIGRP's neighbors. It is sent through untrusted multicast and confirmation is not required.


ACK: Sent in response to update and always unicast. ACKs are not sent reliably.

Wednesday, September 25, 2019

RPR

A strong packet loop, also known as IEEE 802.17, is a standard protocol designed for optimal transmission of data traffic over optical loop networks. Development of the standard began in November 2000 and has undergone several modifications since the initial standard was completed in June 2004.



The RPR packet operates at the Media Access Control (MAC) layer of the Open Systems Interconnection (OSI) model. Provides a packet-based send installation, aimed at improving the efficiency of Ethernet and IP services. RPR provides improved bandwidth utilization and performance, faster deployment speed and equipment and improved operating costs.

The control signal is transmitted in the opposite direction to the traffic of the data carrying its information. For example, if the outer loop holds the data, the inner loop has its own control information.

The RPR node can dynamically negotiate bandwidth problems with other nodes. It's a quality conscious installation (QoS) that can schedule traffic in priority. This prevents congestion and reduces failed transmissions. If any link is broken in any loop, the data will continue to be transmitted through title and editing methods. In the address, all nodes are notified of the broken link and redirect their traffic. In the envelope, data traffic is returned to the last node before the connector is broken and routed to the destination station through the other loop.

Overlay Network

An overlay network is a computer network based on another network. An overlay network separates network services from the underlying infrastructure by encapsulating a packet into another packet.



An overlay network is a communications network based on another network and compatible with its infrastructure. An overlay network separates network services from the underlying infrastructure by encapsulating a packet into another packet.

Simply put, a nested network is a virtual network of nodes and logical links, which are built on an existing network. Using nested networks, multiple layers of network abstraction can be created to run virtual network layers, which correspond to the physical infrastructure.

In a nested network, nodes are connected by default or logical links. These nodes can be connected through physical connections in core networks. The network overlapped on the P2P file system consists of nodes. These nodes share a file-sharing system and logical links exist between them. All nodes in a nested network are connected to each other by logical or virtual links and each of these links corresponds to a path in the underlying network.

LiFi

LiFi uses light to transmit data, while WiFi uses electromagnetic waves at radio frequencies to transmit data. Due to the low interference caused by light compared to radio frequency waves, it is used in denser environments.



LiFi is a wireless optical network technology that uses light-emitting diodes to transfer data. LiFi is designed to use LED lamps similar to those currently used in many energy-efficient homes and offices.

Li-Fi is a wireless communication technology that uses light to transmit data and locations between devices. The term was first introduced by Harald Haas during the 2011 TEDGlobal talk in Edinburgh.

LiFi can transmit up to 100 Gbps and maybe more, but this will require a change in lighting technology. The latest news report that LiFi is 100 times faster than WiFi. The average Wi-Fi speeds were supposed to be 10 Mbps and the LiFi speed could reach 1 Gbps.

For example, in corridors, waiting rooms, patient rooms and operating theaters, Li-Fi technology will allow a light communication network, which will eliminate electromagnetic interference problems from smartphones and use of hospital Wi-Fi.

Increase Bandwidth

To resolve the issue, you must first determine the bandwidth and its impact on connection speeds. When it comes to computers, bandwidth refers to the amount of data that can be downloaded or downloaded from your computer in a specified time period. They are measured and expressed as bits per second (bps).



Your bandwidth is mainly determined by your device, your router, your Internet Service Provider (ISP) and the bandwidth you promised. However, even if your nodes have stated that your connection speed is up to 20 Mbps, this does not mean that you will always get the maximum bandwidth, especially if you connect multiple devices to the same network and use them all at once. Why?

Its bandwidth is similar to a two-lane highway where all cars (data) travel at the same speed. Driving is enjoyable as long as there are not many cars. Busier, slower will go. More lanes, or bandwidth, on the road can solve the problem.

3 simple solutions you can try:

If you have a basic internet plan. -> Upgrade to a better plan with more bandwidth.
If your ISP does not provide enough bandwidth for your needs -> get rid of it and go to another ISP.
If you don't want to invest in an update but you need more speed. -> Try to limit the number of devices connected to the Internet or ask your family members to pause their downloads for a while. You can also turn off Wi-Fi and use a wired connection.

Tuesday, September 3, 2019

Synchronous Optical Network (SONET)

Synchronized optical networks (SONET) are a unified digital communication protocol used to transfer large amounts of data over relatively long distances using a fiber optic support.



SONET is a communication protocol, developed by Bellcore, used to transmit a small amount of data over relatively large distances using optical fiber. With SONET, multiple digital data streams are transmitted simultaneously over optical fiber.

SONET is widely used in the telephone network and is one of the first large-scale optical transmission systems. Digital information is transmitted over optical fiber using a LED source or a laser source. The frame format used by SONET is the synchronous transfer signal (STS), with STS-1 as a base level signal at 51.84 Mbps. The STS-1 tire can be carried in the OC-1 signal.

SONET is no different from other technologies, but the hardware is produced to provide better configuration and reliable services to its users. SONET can use a generator to return long distances. This device improves signals that have already traveled long distances. The signals are transferred into electrical signals and then regenerated into high-power signals. The addition of projection multiplexers (ADM) is a common part of SONET. ADMs are designed to fully support the SONET network architecture.

Saturday, August 31, 2019

E-carrier

E1 is a European digital transmission format invented by ITU-T and given the name of the European Conference on Postal and Telecommunications Management (CEPT). It is equivalent to the coordination of transport systems in North America. E2 to E5 are carriers in increasing multiples of E1 format.



The electronic carrier is part of the series of advanced transport systems for the digital transmission of multiple simultaneous telephone calls by time division multiplexing. E1 consists of 32 channels, which can be used to make simultaneous voice calls and each channel is called a "time period" (TS). In accordance with the ITU-T recommendations, two reporting and synchronization time periods are assigned. Therefore, E1 can carry 30 voice calls or data connections simultaneously.

Similar to T-1 in North America, E1 is the European format for digital transmission. E1 carries 2 Mbps signals (32 channels at 64 kbps, with two dedicated signal and control channels), compared to T1, which carries 1.544 Mbps signals (24 channels at 64 kbps).

The E1 connection works on two separate sets of wires, usually an unsecured twisted pair (balanced cable) or using coaxial (unbalanced cable). The maximum peak signal is encoded at 3 volts with pulses using the method to avoid prolonged periods without polarity changes. Data line speed is 2.048 Mbps

NDP

Neighbor Discovery Protocol (NDP, ND) is a protocol in the set of Internet protocols used with Internet Protocol Version 6 (IPv6).


IPv6 Neighbor Discovery Protocol (NDP) performs functions similar to those provided in the IPv4 address resolution protocol (ARP). NDP also supports the concept of proxy, when a node has an adjacent device capable of forwarding packets on behalf of the node.

Neighbor Discovery Protocol is used in conjunction with the latest version of Internet Protocol (IPv6). Its main function is to analyze IPv6 addresses in valid MAC addresses and the primary hardware address of the devices involved. In IPv4, this function uses the ARP (Address Resolution Protocol). All selected addresses are stored as information in the adjacent cache. This buffer not only communicates local addresses of nearby customers to network users, but provides them with additional information, for example, to check availability.

As mentioned above, NDP is also involved in customizing the standard portal. With the addition of the Router Advertising Protocol (RA), it is possible to specify both the standard router and the valid network prefixes: two key parameters for network configuration. Finally, the network protocol, which only exchanges data within a network, acts as a support protocol for dynamic address configuration. This process is also known as "automatic stateless address configuration" (SLAAC).