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ISDN stands for integrated service digital network. It is a telephone switched network which integrates voice and data over a digital line simultaneously. It also provides packet switched networks.ISDN supports a variety of services which are as follows −Voice callsVideo textsElectronic mailDatabase accessFacsimileTeletextData transmission and voiceConnection to internetElectronic Fund transferImage and graphics exchangeDocument storage and transferAudio and Video ConferencingThe figure given below depicts ISDN −Channels of ISDNISDN has mainly three channels, which are as follows −B-channel − It offers a speed of around 64kbps, which can be used for home purpose.D-channel − It offers speeds ranging from 16 to 64 ... Read More
To compute last of group values, use the groupby.last() method. At first, import the required library with an alias −import pandas as pd;Create a DataFrame with 3 columns −dataFrame = pd.DataFrame( { "Car": ['BMW', 'Lexus', 'BMW', 'Tesla', 'Lexus', 'Tesla'], "Place": ['Delhi', 'Bangalore', 'Pune', 'Punjab', 'Chandigarh', 'Mumbai'], "Units": [100, 150, 50, 80, 110, 90] } ) Now, group DataFrame by a column −groupDF = dataFrame.groupby("Car")Compute last of group values and resetting index −res = groupDF.last() res = res.reset_index()ExampleFollowing is the complete code. The last occurrence of repeated values are displayed i.e. last of group values ... Read More
Let us understand the concept of piconet and scatternet before learning the differences between them.PiconetA piconet is a network created by connecting multiple wireless devices using Bluetooth technology. In a piconet network a master device exists, this master device cm gets connected to 7 more slave devices.It includes the master the number of devices that can be connected is limited to 8. Due to less number of devices active at a time the usage of channel band width is not more.Number of devices that can be connected is limited to 8. It is applicable for devices belonging to small areas.Given ... Read More
A group of communication in a computer network is multicasting, where a sender sends data to multiple receivers simultaneously. Simply in Multicasting we send data across a computer network to several users at the same time. It supports one-to-many and many-to-many data transmission across LANs or WANs.User Datagram Protocol (UDP)The most common protocol (transport layer protocol) to use multicast addressing is User Datagram Protocol (UDP).User datagram protocol is defined as the simplest transport layer communication protocol available of the Transmission Control Protocol/Internet Protocol (TCP/IP) protocol suite. It is one of the core members of the Internet protocol suite. It Increases ... Read More
Open Shortest Path First (OSPF) is a router protocol used to find the best path for packets as they pass through a set of connected networks.This protocol is designated by the Internet Engineering Task Force (IETF) one of the Interior Gateway Protocols (IGPs) aimed at traffic moving around within a larger autonomous system network like a single enterprise's network, which may in turn be made up of many separate local area networks linked through routers.ExplanationArea 1 Border router Area 0 Backbone zone Border router Area 2 OSPF.OSPF protocol is called a link state routing protocol, which maintains link state databases. ... Read More
To filter on the basis of sum of columns, we use the loc() method. Here, in our example, we sum the marks of each student to get the student column with marks above 400 i.e. 80%.At first, create a DataFrame with student records. We have marks records of 3 students i.e 3 columns −dataFrame = pd.DataFrame({ 'Jacob_Marks': [95, 90, 75, 85, 88], 'Ted_Marks': [60, 50, 65, 85, 70], 'Jamie_Marks': [77, 76, 65, 45, 50]}) Filtering on the basis of columns. Fetching student with total marks above 400 −dataFrame = dataFrame.loc[:, dataFrame.sum(axis=0) > 400]ExampleFollowing is the complete ... Read More
Internet Control Message Protocol (ICMP) shares error reporting and device status messages which can be further divided into specific message types with their codes.These message types can be divided into two categories −Error Reporting MessagesQuery MessagesThese message types are shown below −Error Reporting MessagesThese are messages which are sent when an error is reported by ICMP protocol.Some of common messages under this category are as follows:Destination Unreachable (Type 3)One of the most common error reporting messages occurs when the router is unable to locate the path of the packet where it is needed to be delivered and in this case ... Read More
There are three security issues that are applicable to the IP protocol −Packet SniffingPacket ModificationIP SpoofingLet us discuss each issue in detail.Packet SniffingA guest may intercept an IP packet and create a copy of it.The packet sniffing is generally a passive attack, where the attacker does not change the contents of the packet.Packet sniffing attack is difficult to detect because here the sender and receiver doesn’t know that the packet has been copied.Even though the packet sniffing cannot be stopped, the encryption of the packet can make the attacker’s effort useless. Still the attackers may sniff the packet, but the ... Read More
The Internet Protocol version 4 (IPv4) is called the fourth version in the development of the Internet Protocol. Its address is a 32-bit address which uniquely defines the connection that means here each address defines one, and only one, connection to the Internet.If a device has two connections to the Internet, via two networks, then we call it has two IPv4 addresses.IPv4 addresses are universal in a sense where the addressing system must be accepted by any host that wants to be connected to the Internet.Ipv4 address notationThere are three notations to show an IPv4 address which are as follows ... Read More
To select first periods of time series based on a date offset, use the first() method. At first, set the date index with periods and freq parameters. Freq is for frequency −i = pd.date_range('2021-07-15', periods=5, freq='3D')Now, create a DataFrame with above index −dataFrame = pd.DataFrame({'k': [1, 2, 3, 4, 5]}, index=i) Fetch rows from first 4 days i.e. 4D −dataFrame.first('4D')ExampleFollowing is the complete code − import pandas as pd # date index set with 5 periods and frequency of 3 days i = pd.date_range('2021-07-15', periods=5, freq='3D') # creating DataFrame with above index dataFrame = pd.DataFrame({'k': [1, 2, 3, ... Read More