Model for the Physical Layer and the Radio Channel in Dedicated Short Range Communication S

Dynamic topology:As the channel of communicationchanges, some of the neighbors who were reachable on theprevious channel might not be reachable on the currentchannel and vice versa. As a result the topology of the network changes with the change in frequency of operation resulting in route failures and packet loss.Heterogeneity:Different channels may support differenttransmission ranges, data rates and delay characteristics.Spectrum-Handoff delay:For each transition from onechannel to another channel due to the PU’s activity, thereis a delay involved in the transition called Spectrum- Handoff delay.All these factors decrease the predictability of the cause oftransit-delay and subsequent packet loss on the network. Thetime latency during channel hand-off in cognitive networksmight cause the TCP round trip timer to time out. TCP willwrongly recognize the delays and losses due to the abovefactors as network congestion and immediately take steps toreduce the congestion window size knowing not the cause ofpacket delay. This reduces the efficiency of the protocol insuch environments.动态技术：随着信道通信的变化，一些邻进信道的用户在原信道没有发生变化而在新信道发生变化，或者相反。

2024年山东省德州市德城区中考一模英语试题一、听力选择1．A．Sure, I will.B．sorry, I won’t.C．OK, I will.2．A．That’s right.B．That’s a good idea.C．That’s a pity.3．A．Yes, I’m full B．Yes, please.C．No, I don’t.4．A．An engineer B．Be helpful.C．You bet.5．A．That’s great.B．I’m sorry to hear that.C．Nice to meet you.二、听力匹配录音中有三个句子，每个句子对应一幅图片，每个句子听两遍，然后选择与句子内容相对应的图片。

6．1. 2. 3.三、听力选择7．How long has the woman been in Australia?A．For 6 weeks.B．For 2 weeks.C．For 8 weeks.8．Where does this conversation probably happen?A．On a bus.B．In a library.C．At a theatre.9．What will the woman probably buy?A．Some coffee.B．A basketball.C．Some apples.10．Why didn’t Maria go to school?A．Because she had to look after her mother.B．Because she had to do some shopping.C．Because she had to finish her homework.11．What does the woman look like?A．tall and thin B．short and weak C．big eyes录音中有一段长对话，听对话两遍后，从每小题A、B、C中选出能回答所给问题的正确答案。

Cisco Nexus 9332C and 9364C Fixed Spine SwitchesData sheet Cisco publicContentsProduct overview 3 Specifications 4 Performance and scalability 5 Regulatory Standards Compliance 7 Supported optics pluggable 7 Software licensing 8 Ordering information 8 Warranty 10 Cisco environmental sustainability 10 Service and Support 11 Cisco Capital 11 For more information 11Product overviewBased on Cisco® Cloud Scale technology, this platform supports cost-effective, ultra-high-density cloud-scale deployments, an increased number of endpoints, and cloud services with wire-rate security and telemetry. The platform is built on modern system-architecture designed to provide high performance and meet the evolving needs of highly scalable data centers and growing enterprises.The product is designed to support innovative technologies such as Media Access Control Security (MACsec), Virtual Extensible LAN (VXLAN), tunnel endpoint VTEP-to¬-VTEP overlay encryption, CloudSec and Streaming Statistics Export (SSX)1. MACsec is a security technology that allows traffic encryption at the physical layer and provides secure server, border leaf, and leaf-to-spine connectivity. SSX is hardware-based, consisting of a module that reads statistics from the ASIC and sends them to a remote server for analysis. Through this application, users can better understand network performance without any impact on the switch control plane or CPU.Cisco provides two modes of operation for Cisco Nexus® 9000 Series Switches. Organizations can use Cisco NX-OS Software to deploy the switches in standard Cisco Nexus switch environments (NX-OS mode). Organizations can also deploy the infrastructure that is ready to support the Cisco Application Centric Infrastructure (Cisco ACI™) platform to take full advantage of an automated, policy-based, systems-management approach (Cisco ACI mode).Switch modelsThe Cisco Nexus 9364C Spine Switch is a 2-Rack-Unit (2RU) spine switch that supports 12.84 Tbps of bandwidth and 4.3 bpps across 64 fixed 40/100G QSFP28 ports and 2 fixed 1/10G SFP+ ports (Figure 1). Breakout cables are not supported. The last 16 ports marked in green are capable of wire-rate MACsec encryption.1 The switch can operate in Cisco ACI Spine or NX-OS mode.Figure 1.Cisco Nexus 9364C Switch1 See the latest release notes for additional information here.The Cisco Nexus 9332C is a compact form-factor 1-Rack-Unit (1RU) spine switch that supports 6.4 Tbps of bandwidth and 4.4bpps across 32 fixed 40/100G QSFP28 ports and 2 fixed 1/10G SFP+ ports (Figure 2). Breakout cables are not supported. The last 8 ports marked in green are capable of wire-rate MACsec encryption.2 The switch can operate in Cisco ACI Spine or NX-OS mode.Figure 2.Cisco Nexus 9332C SwitchSpecificationsTable 1.Cisco Nexus 9300 ACI Spine Switch specifications2 See the latest release notes for additional information here.3 930W-DC PSU is supported in redundancy mode if 3.5W QSFP+ modules or Passive QSFP cables are used and the system is used in 40°C ambient temperature or less; for other optics or higher ambient temperatures, 930W-DC is supported with 2 PSU’s in nonredundancy mode only.4 750W AC PSU is compatible only with software versions ACI-N9KDK9-14.2 or NXOS-9.3.3 and onwards5 HVAC/HVDC support is on the roadmap for future releases confirmed.Performance and scalabilityTable 2 lists the performance and scalability specifications for the Cisco Nexus 9364C and 9332C switches.Table 2.Performance and scalability specifications* LPM-heavy values are the maximum numbers.** 127 VLANs out of 4096 are reserved.Refer to the Cisco Nexus 9000 Series Verified Scalability Guide for the latest, exact scalability numbers validated for specific software.Regulatory Standards ComplianceTable 3 summarizes regulatory standards compliance for the Cisco Nexus 9364 and 9332C switches. Table 3.Regulatory Standards Compliance: Safety and EMC* Cisco Nexus N9K-C9364C passes EMC Radiated Emissions standards in all configurations, with the only exception being if > 40 pluggable optics of Cisco QSFP-100G-SR4-S, Part# 10-3142-02 (or 10-3142-01) are used.Supported optics pluggableFor details on the optical modules available and the minimum software release required for each supported optical module, visithttps:///en/US/products/hw/modules/ps5455/products_device_support_table_list.html.Software licensingThe software packaging for the Cisco Nexus 9000 Series offers flexibility and a comprehensive feature set. The default system software has a comprehensive Layer 2 security and management feature set. To enable additional functions, including Layer 3 IP unicast and IP multicast routing and Cisco Nexus Data Broker, you must install additional licenses. The licensing guide illustrates the software packaging and licensing available to enable advanced features. For the latest software release information and recommendations, refer to the product bulletin at https:///go/nexus9000.Ordering informationTable 4 presents ordering information for the Cisco Nexus 9300 ACI Spine Switch.Table 4.Ordering information6 The 1100W DC power supply (NXA-PDC-1100W-PE/PI) is shipped with a connector already plugged into the power supply; a cable is therefore not required. For more product specification information, please see the Hardware Installation Guide here.WarrantyThe Cisco Nexus 9300 switch has a 1-year limited hardware warranty. The warranty includes hardware replacement with a 10-day turnaround from receipt of a Return Materials Authorization (RMA).Cisco environmental sustainabilityInformation about Cisco’s environmental sustainability policies and initiatives for our products, solutions, operations, and extended operations or supply chain is provided in the “Environment Sustainability” section of Cisco’s Corporate Social Responsibility (CSR) Report.Reference links to information about key environmental sustainability topics (mentioned in the “Environment Sustainability” section of the CSR Report) are provided in the following table:Reference links to product-specific environmental sustainability information that is mentioned in relevant sections of this data sheet are provided in the following table:7 NXK-ACC-KIT-1RU/2RU are on the roadmap for future releases.© 2022 Cisco and/or its affiliates. All rights reserved. Page 11 of 11Cisco makes the packaging data available for informational purposes only. It may not reflect the most current legal developments, and Cisco does not represent, warrant, or guarantee that it is complete, accurate, or up to date. This information is subject to change without notice.Service and SupportCisco offers a wide range of services to help accelerate your success in deploying and optimizing the Cisco Nexus 9300 switch in your data center. The innovative CiscoServices offerings are delivered through a unique combination of people, processes, tools, and partners and are focused on helping you increase operation efficiency and improve your data center network. Cisco Advanced Services uses an architecture-led approach to help you align your data center infrastructure with your business goals and achieve long-term value. Cisco SMARTnet ™ Service helps you resolve mission-critical problems with direct access at any time to Cisco network experts and award-winning resources.Cisco CapitalFlexible payment solutions to help you achieve your objectivesCisco Capital makes it easier to get the right technology to achieve your objectives, enable business transformation and help you stay competitive. We can help you reduce the total cost of ownership,conserve capital, and accelerate growth. In more than 100 countries, our flexible payment solutions can help you acquire hardware, software, services and complementary third-party equipment in easy,predictable payments. Learn more .For more informationFor more information on the Cisco Nexus 9000 Series and for the latest software release information and recommendations, please visit https:///go/nexus9000.Printed in USA C78-739886-15 04/22。

INTERNATIONAL TELECOMMUNICATION UNIONITU-T G.983.2Implementers’Guide TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU(17 February 2006) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKSImplementers’ Guide for I TU-T Rec. G.983.2(07/2005)ONT management and control interface specification for B-PONSummaryThis document is an Implementers' Guide for ITU-T Recommendation of G.983.2 (07/2005).SourceThis document was agreed by ITU-T Study Group 15 on 17 February 2006.ITU 2005All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU.Table of Contents1.Introduction (1)2.Additions to existing sections of G.983.2 Rev 2. (1)2.1Additions to section (1)2.2Additions to section 5.2 (1)2.3Additions to section 5.3 (1)2.4Additions to section 6.1 (1)2.5Additions to section 6.2 (2)2.6Addition to section 7.1.3 (2)2.7Modification to section 9 (2)3.New sections of G.983.2 Rev 2 (3)IMPLEMENTERS’ GUIDE 1 FOR RECOMMENDATION G.983.2 ONT MANAGEMENT AND CONTROL INTERFACE SPECIFICATION FOR B-PONG.983.2 Rev. 2, OMCI Implementers’ Guide 1SummaryThis document contains informative auxiliary information for the 984.3 standard, aimed to clarify the support of Multimedia over Coax Alliance compliant interfaces.KeywordsB-PON, OMCI, Implemen ters’ Guide1.IntroductionThis Implementers’guide describes the ONT management and configuration interface (OMCI) for Multimedia over Coax Alliance compliant interfaces. Three new managed entities are defined, as well as several modifications to existing entities.*2.Additions to existing sections of G.983.2 Rev 2.2.1Additions to section2 AbbreviationsAdd the following abbreviationsMoCA Multimedia over Coax Alliance2.2Additions to section 5.2Add the following items to list:“PPTP MoCA UNI”2.3Additions to section 5.3Add the following items to the list:“MoCA Ethernet PM History DataMoCA Interface PM History Data”2.4Additions to section 6.1Add the following lines to Table 1.* As there are no published specifications of this interface currently, this material is being put forward as an implementer’s guide. The intention is that once such specifications are published, they will be considered for normative reference in G.983.2.2.5Additions to section 6.2Add the following figure and text at the end of the section.“The MoCA UNI managed entity relationship diagram is shown in Figure 31g.Figure 31g – Managed Entity relation di agram, MoCA UNI”2.6Addition to section 7.1.32.7Modification to section 9.3.New sections of G.983.2 Rev 2Add the following sections.7.3.122 Physical Path Termination Point MoCA UNIThis managed entity represents the points at the MoCA UNI in the ONT where physical paths terminate and physical path level functions (i.e., MoCA function) are performed.RelationshipsAn instance of this managed entity shall exist for each MoCA PPTP port on the ONT. Instances of this managed entity are created automatically by the ONT upon creation/deletion of a circuit pack that supports MoCA UNI functions.Figure 1 Schematic diagram of Loop 3Table X-c/G.983.2 - AVC list for Physical Path Termination Point MoCA UNITable X-d/G.983.2 - Alarm list for Physical Path Termination Point MoCA UNI7.3.123. MoCA Ethernet Performance Monitoring History DataThis managed entity supports the performance monitoring history data for the MoCA Ethernet interface.An instance of this managed entity may be created by the OLT for each instance of the MoCA PPTP managed entity.Table Y/G.983.2 Alarm list for MoCA Ethernet Performance Monitoring History Data B-PO N*This numbering is used with the associated Threshold Data B-PON managed entity. Threshold Data counter 1 indicates the 1st thresholded counter, etc.7.3.124. MoCA Interface Performance Monitoring History DataThis managed entity supports the performance Monitoring History Data for the MoCA interface.An instance of this managed entity may be created by the OLT for each instance of the MoCA PPTP managed entity.Table Z/G.983.2 Alarm list for MoCA Interface Performance Monitoring History Data B-PO N*This numbering is used with the associated Threshold Data B-PON managed entity. Threshold Data counter 1 indicates the 1st thresholded counter, etc.**Because these counters are in a multiple-entry table, and the thresholds are only a single-valued, the sum of counters in the table should be used as the trigger for the threshold AVC._______________。

Theory and Practice of Science and Technology2022, VOL. 3, NO. 6, 4-10DOI: 10.47297/taposatWSP2633-456901.20220306A Novel Hierarchical Structure for Multilayer PerceptronGuodong Ma1, Zerui Qin21The Australian University, Canberra 2600,Australia2New York University,New YorkABSTRACTBased on the training set of the football game FIFA, the project developeda model that could classify the positions of players by their variousnumerical values. The model can select the best position for a player onthe field, providing strong guidance and suggestions for players toimprove the game experience. This problem is a multi-classificationproblem, the most important is to ensure the accuracy of modelclassification. We first try to use a classification model to classify the wholesample directly, and find that the accuracy is low. Then we introduced"hierarchical classification", that is to set up a hierarchical classificationmodel and realize the final classification step by step. We choose theneural network model as the classification model by comparing theaccuracy of four classification models. In the process of implementation,we also optimized the basic hierarchical classification model innovatively,which greatly improved its performance.KEYWORDSNeural Network; Multilayer Perceptron; Hierarchical Structure1　IntroductionThe project evaluates and classifies given players by collecting, processing, and analyzing various data (age, height, weight, physical, value, position, pace, shooting, dribbling, defending) of football players worldwide. Before, there have been researches on the position distribution of players, the selection of the top ten players, and overall prediction of a FIFA player. In real games, however, players are often placed in positions that do not fit their player stats. In this project, we train the player data of various league in the world, compare the efficiency of multiple classification models, and use the optimal model to achieve different degrees of position classification.2　DatasetThe project uses the FIFA complete player data sets in Kaggle[1] and FIFA's official website[2][3] to build the project model. The data sets contains 6 data sets provided the players data for career mode from FIFA 15 to FIFA 20. Each data set includes about 18,000 player information records of 104 aspects (e.g. id, name, various skill scores, etc.). This database has a lot of football analysis that can be studied and analyzed in depth by researchers. FIFA 20 data set is used as a training set to build a model, and FIFA 19 data set is used as a testing set to detect the model.Theory and Practice of Science and Technology 3　Solution(1)　Data set preprocessingThe project first deals with the wrong data (serial, missing, format error). The number of serial and format error samples in the data set is small, and these sample data are discarded from the data set. The project explores the reasons for the missing data.According to the Figure 1, The missing value is generated because the "goalkeeper" has no record meaning in some specific features; similarly, other players have no record meaning in the goalkeeper features. Therefore, there are no recorded values on these features. The project first excludes the "goalkeeper" samples in the data set, and then deleted the meaningless features from the remaining data set. The missing value is no longer included in the current data set.In order to better build the player position classification model, the project only retains 49 useful features, and the data type saved by all characters is changed to numeric form.The label of the data set originally has 11 categories. In order to better classify the label, the 11 categories are summarized into 4 categories and 9 categories, which are recorded in digital form (i.e. 0,1,2,3 and 0, 1...,8). Before implementing classification, the project explores the influence of the left and right feet on the position in advance. The project compared the ratio of the left and right feet to the left and right field positions (forward-field, mid-field, center-back-field, side-back-field). According to the Figure 2 , we can see that for the side-back-field players, the left-footed players are basically on the left field, and the right-footed players are basically on the right field. But for the midfield, backfield and center-side the use of the left and right feet of a player has little to do with being on the left and right side of the field. Therefore, in the classification process, we will finally further classify the side-back-field players (labeled L/RB) into two categories, LB and RB.(2)　Classification structure1)　Basic hierarchical classification structureAs shown in Figure 3, the algorithm first builds four classification models [4] for all players. Because the features of the players whose label is "GK" are different from those of the other three types of players, the algorithm first classifies the players with GK features into the goalkeeper category. Next, the algorithm builds a model to classify players into three categories by training set (2020 data set):"Forward", "Mid", and "Back".Figure 1　Missing value proportion 5Guodong Ma and Zerui Qin Through the classification model in the first step, four classifications will be obtained as a result. Next, the project further categorizes the "Forward", "Mid", and "Back" categories into 8 categories "ST", "R/LW", "CAM", "CDM", "CM", "R/LM" ,"CB", and "L/RB"[5]. The classification model in the second step is still built with the MLP model, and the test set is used to get the accuracy of the second-step classification (model1, model2, model3).Because we find that the left and right feet have a great influence on the left and right guards based on the preprocessing, the project finally divided the "L/RB" into two categories.The project compares 4 types of classification models (Logistic regression, decision tree [6], QDA, MLP [7]). Considering the efficiency and accuracy of the model, MLP is the optimal model. AndtheFigure 2　Flow of classificationFigure 3　Flow of classification 6Theory and Practice of Science and Technology7 project applies MLP to the algorithm.2)　Classification improvement Array second layer outputFigure 4　When analyzing the accuracy of the model, we found that there would be some wrong classifications in the results of the second layer. For example, after the second classification, in theforward result, there will be some players who are not forwards. We decided to separate out theplayers in this section to improve our accuracy. Array Figure 5　advanced classification modelGuodong Ma and Zerui Qin As shown in the figure 5, we optimized its structure based on the existing classification model. We add an additional category to the existing categories of the three models at the third level. Then the data belonging to this category are extracted for further classification.As shown in the figure 6, take the first classification model of the third layer, which is responsible for classifying the data with the "front field" label from the previous layer. In the previous model, we only divided it into two categories: ST, L/RW. In the optimized model, we added a new category "other" to store data other than the first two, and then we used the next level of classification model to divide the data into all categories except ST and L/RW. This optimization will greatly increase the accuracy of the classification model. In fact, we can add more layers and repeat this process many times with satisfactory accuracy.In addition, PCA is also used to reduce model complexity by removing variables that are not closely related to classification results.Due to the large difference deviation between different players and different positions, the accuracy and error are different in different categories. Therefore, Boosting algorithm can be introduced in the future to make the model focus on samples with large error, so as to achieve optimization effect.(3)　Model constructionAs shown in Figure 7, the MLP classification model built by the project has two hidden layers.Figure 6　advanced classification model detailFigure 7　MLP diagram 8Theory and Practice of Science and Technology The input layer will undergo a normalization process(as shown in formula 1):Normalization formula:The batch of the model is 64, and it has been trained 300 iterations to get the best accuracy. We formulate this MLP as our core classification model.4　Results AnddiscussionThe test accuracy for the models is shown in Figure 8. The first column shows the test accuracy for the classification model that do not use the c structure, only use one MLP classifier to classify 10 classes. The second column shows the test accuracy for the hierarchical classification model before the improvement. The third column shows the test accuracy for the hierarchical classification model after the improvement.From the table, we can see that the hierarchical classification model has better performance than the non hierarchical classification model. Also, the hierarchical classification model after the improvement has better performance than the original hierarchical classification model. But the complexity of our model is high, the over fit of the training data can be a problem. In the future, we will try to increase the number of layers in the improved model layer, find a balance for how many layers we should use in the model. For each classifier in the model, we will introduce boosting algorithm and other training method to improve each classifier in each layer, this might decrease the influence of over fitting.References[1] S. Leone, "Fifa 20 complete player dataset," https:/// stefanoleone992/fifa-20-complete-player-dataset.Figure 8　Test accuracy 9Guodong Ma and Zerui Qin 10[2] X. wang, "A crawler for player data analysis of fifa football games," https: ///developer/news/368808.[3] FIFA, "Fifa players," https:///.[4] J.-P. Alemeida, A. Rutle, and M. Wimmer, "Preface to the 6th international workshop on multi-level modelling (multi2019)," in 2019 ACM/IEEE 22nd International Conference on Model Driven Engineering Languages and Systems Companion (MODELS-C), 2019, pp. 64–65.[5] francefootball, "francefootball," https://www.francefootball.fr/.[6] S. Mitrofanov and E. Semenkin, "An approach to training decision trees with the relearning of nodes," in 2021International Conference on Information Technologies (InfoTech), 2021, pp. 1–5.[7] L. Abhishek, "Optical character recognition using ensemble of svm, mlp and extra trees classifier," in 2020International Conference for Emerging Technology (INCET), 2020, pp. 1–4.。

1. Which is true when a broadcast is sent out in an Ethernet 802.3 LAN?A. The broadcast is sent only to the default gateway.B. The broadcast is sent only to the destination hardware address in the broadcast.C. The broadcast is sent to all devices in the collision domain.D. The broadcast is sent to all devices in the broadcast domain.2. PDUs at the Network layer of the OSI are called what?A. TransportB. FramesC. PacketsD. Segments3. Which two statements about a reliable connection-oriented data transfer are true?A. Receiving hosts acknowledge receipt of data.B. When buffers are full, packets are discarded and are not retransmitted.C. Windowing is used to provide flow control and unacknowledged data segments.D. If the transmitting host’s timer e xpires before receipt of an acknowledgment, the transmitting host drops the virtual circuit.4. PDUs at the Data Link layer are named what?A. TransportB. FramesC. PacketsD. Segments5. Segmentation of a data stream happens at which layer of the OSI model?A. PhysicalB. Data LinkC. NetworkD. Transport6. What term is used if you are using the processes of placing frames from one network system into the frame of another network system?A. FramingB. EncapsulatingC. TunnelingD. Frame Relay7. What does the Data Link layer use to find hosts on a local network?A. Logical network addressesB. Port numbersC. Hardware addressesD. Default gateways8. What were the key reasons the ISO released the OSI model? (Choose two.)A. To allow companies to charge more for their equipmentB. To help vendors create interoperable network devicesC. To help vendors create and sell specialized software and hardwareD. So the IBM mainframe would be replaced with the PCE. So the industry could create a standard for how host computers workF. So that different vendor networks could work with each other9. Which statement about Ethernet networks is true?A. Full duplex can run over 10Base2.B. Full duplex requires a point-to-point connection when only two nodes are present.C. Full-duplex Ethernet can be used to connect multiple hosts to a single switch interface.D. Half duplex uses the cut-through LAN switch method.10. What is used at the Transport layer to stop a receiving host’s buffer from overflowing?A. SegmentationB. PacketsC. AcknowledgmentsD. Flow controlE. PDUs11. Which layer of the OSI provides translation of data?A. ApplicationB. PresentationC. SessionD. TransportE. Data Link12. When data is encapsulated, which is the correct order?A. Data, frame, packet, segment, bitB. Segment, data, packet, frame, bitC. Data, segment, packet, frame, bitD. Data, segment, frame, packet, bit13. Which of the following is not an advantage of a layered model?A. Allows multiple-vendor development through standardization of network componentsB. Allows various types of network hardware and software to communicateC. Allows changes to occur in all layers without having to change just one layerD. Prevents changes in one layer from affecting other layers, so it does not hamper development14. What are two purposes for segmentation with a bridge?A. Add more broadcast domains.B. Create more collision domains.C. Add more bandwidth for users.D. Allow more broadcasts for users.15. What does the term “Base” indicate in 100Ba se-TX?A. The maximum distanceB. The type of wiring usedC. A LAN switch method using half duplexD. A signaling method for communication on the network16. What is the maximum distance of 100BaseT?A. 100 feetB. 1000 feetC. 100 metersD. 1000 meters17. Which of the following would describe a Transport layer connection that would ensure reliable delivery?A. RoutingB. AcknowledgmentsC. SwitchingD. System authentication18. What are two reasons to segment a network with a bridge?A. Increase the amount of collision on a segment.B. Decrease the amount of broadcast on a segment.C. Reduce collisions within a broadcast domain.D. Increase the number of collision domains.19. Which of the following types of connections can use full duplex? Select all that apply.A. Hub to hubB. Switch to switchC. Host to hostD. Switch to hubE. Switch to host20. Which of the following describes the Physical layer connection between a DTE (router) and a DCE (CSU/DSU) device?A. IP, IPX, AFPB. TCP, UDPC. EIA/TIA 232, V.35, X.21, HSSID. FTP, TFPT, SMTP21. Which of the following would be used to connect a router to an Ethernet switch?A. AB. BC. CD. None of the figures22. Which of the following are Presentation layer protocols? Select all that apply.A. TFTPB. IPC. RTFD. QuickTimeE. MIDI23. Which of the following are considered some reasons for LAN congestion? Select all that apply.A. Bill GatesB. Low bandwidthC. Too many users in a broadcast domainD. Broadcast stormsE. RoutersF. MulticastingG. Any Cisco competitor24. Which of the following are reasons for breaking up a network into two segments witha router? (Choose two.)A. To create fewer broadcast domainsB. To create more broadcast domainsC. To create one large broadcast domainD. To stop one segment’s broadcasts from being sent to the second segment25. How do you connect to a router using HyperTerminal?A. Connect the Ethernet port of your host to the Ethernet interface of the router using a rolled cable.B. Connect the COM port of your host to the Ethernet port of your router using a straight-through cable.C. Connect the Ethernet port of your host to the console port of the router using a rolled cable.D. Connect the COM port of your host to the console port of the router using a crossover cable.E. Connect the COM port of your host to the console port of the router using a rolled cable.Answers to Review Questions1. D. A broadcast sent on an Ethernet 802.3 LAN will go to all devices in the Ethernet broadcast domain.2. C. Protocol Data Units are used to define data at each layer of the OSI model. PDUs at the Network layer are called packets.3. A, C. When a virtual circuit is created, windowing is used for flow control and acknowledgment of data.4. B. Data is encapsulated with a media access method at the Data Link layer, and the Protocol Data Unit (PDU) is called a frame.5. D. The Transport layer receives large data streams from the upper layers and breaksthese up into smaller pieces called segments.6. C. If you place a frame inside another frame, this is called tunneling.7. C. MAC addresses, also called hardware addresses, are used to uniquely identify hosts on a local network.8. B, F. The ISO wanted all vendors equipment to be able to work together, which is the main reason for the OSI model. The second and last options are saying the same thing. 9. B. The best answer for this question is the second option. Full duplex cannot run over 10Base2; you cannot connect multiple nodes to a single switch port and run full duplex; and cut-through has nothing to do with half- or even full-duplex Ethernet.10. D. Flow control stops a device from overflowing its buffers. Even though flow control can be used at many layers, the Transport layer’s reliable connection provides the best flow control available in the model.11. B. The only layer of the OSI model that can actually change data is the Presentation layer.12. C. The encapsulation method is: data, segment, packet, frame, bit.13. C. The largest advantage of a layered model is that it can allow application developers to change the aspects of a program in just one layer of the layer model’s specifications.14. B, C. Bridges break up collision domains, which allow more bandwidth for users.15. D. Baseband signaling is a technique that uses the entire bandwidth of a wire when transmitting. Broadband wiring uses many signals at the same time on a wire. These are both considered an Ethernet signaling type.16. C. 10BaseT and 100BaseT have a distance limitation of 100 meters.17. B. A reliable Transport layer connection uses acknowledgments to make sure all data is transmitted and received reliably.18. C, D. Bridges increase the number of collision domains in a network, which provides more bandwidth per user, which means less collision on a LAN.19. B, C, E. Hubs cannot run full-duplex Ethernet. Full duplex must be used on a point-to-point connection between two devices capable of running full duplex. Switches and hosts can run full duplex between each other, no problem.20. C. The EIA/TIA 232, V.35, X.21, and HSSI are examples of Physical layer specifications.21. C. A straight-through Ethernet cable is used to connect a host or router to an Ethernet switch.22. C, D, E. The Presentation layer defines many protocols; RTF, Quick-Time, and MIDI are correct answers. IP is a Network layer protocol; TFTP is an Application layer protocol.23. B, C, D, F. Although, Bill Gates is a good answer for me, and Cisco probably would like the last option, the answers are: not enough bandwidth, broadcast storms, too many users, and multicasting.24. B, D. Routers, by default, break up broadcast domains, which means that broadcasts sent on one network would not be forwarded to another network by the router.25. E. From a COM port of a PC or other host, connect a rolled cable to the console port of the router, start HyperTerminal, set the BPS to 9600 and flow control to None, then press Enter to connect.。

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