Cisco Systems 2 manual 138

Page 138

640 - 607

Steve McQuerry. Interconnecting Cisco Network Devices. (Cisco Press: 2000) page 22.

Q. 223

Which two statements about a reliable connection oriented data transfer are true? (Choose two)

A.Recipients acknowledge receipt of data.

B.When buffers are filled to capacity, datagrams are discarded and not re transmitted.

C.Windows are used to control the amount in outstanding acknowledged data segments.

D.If the segments timer expires between receipt of an acknowledgement the sender drops the connection.

E.The receiving device waits for acknowledgements from the sending device before accepting more data segments.

Answer: A, C.

Explanation:

Connection orientated protocols, such as TCP, communication use acknowledgement of packets. This is how error control is possible. To govern the flow of data between devices, TCP uses a flow control mechanism. The receiving TCP reports a “window” to the sending TCP. This window specifies the number of octets, starting with the acknowledgment number, that a receiving TCP is currently prepare to receive.

TCP windows sizes are variable during the lifetime of the connection. Each acknowledgment contains a window advertisement that indicates how many bytes the receiver can accept. TCP also maintains a congestion control window that is normally the size as the receiver’s window but is cut in half when a segment is lost (for example, there is congestion). This approach permits the window to be expanded or contracted as necessary to manage buffer space and processing.

Incorrect Answers:

B is incorrect; with connection orientate protocols packet delivery is guaranteed. Packet will not be dropped. Flow control (windowing) addresses the buffer issue.

D is incorrect; if the sending system does not receive an acknowledgement from the receiving system then the packet will be resent.

E is incorrect; the receiving device sends the acknowledgement of packets and this states how much data the receiving device can receive.

Steve McQuerry. Interconnecting Cisco Network Devices. (Cisco Press: 2000) pages 213-4.

Q. 224

Which three functions are supported by connection oriented services? (Choose three)

A.Connection parameters are synchronized

B.Any loss or duplication of packets can be corrected

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Contents Ccna Important Note Please Read Carefully Incorrect Answers Which command displays the configuration register setting?Answer D Answer D ExplanationAnswer C Explanation Answer B ExplanationExhibit Answer a Explanation Answer B During encapsulation in which order is information packaged? Answer CAnswer E Explanation Answer A, B, E Answer F Explanation What is the result of segmenting a network with a bridge? Answer aPhysical layer Data layer Network layer Transport layer Host 1-1 can ping Host Answer A, B and E Answer B, D, FAnswer A, B, D 640 Answer A, D, F Answer B, C, E Answer A, D Cable #1 Cable #2 Cable #3 Cable #4 Answer A, B 640 Answer D What is the likely cause of this problem? Answer A, C, D Answer Answer B, F 640 RIP Ospf Eigrp Igrp Answer Explanation Answer A, B, D, E Answer D Is incorrect this is not a valid command Answer B Answer D Answer A, C, D, E Which of the following are true? Answer EWhat is a benefit of a virtual LAN VLAN? Answer C, D Answer B Given the configuration example Answer D, E Explanation Answer A, E, F Which two statements about IP RIP are true? Choose two Answer D, FHow does inter-VLAN communication take place? Answer A, B, C, and D CSMA/CD Answer A, D Which two statements about a bridge are true. Choose two Which statement about an IP network is true? 10.0.0.0 to 172.16.0.0 to 192.168.0.0 to Answer A, B, C, GExplanation Which statement is true? Answer A, B, D Explanation Incorrect OptionsAnswer A, C, E Answer a and B Which two protocol tools use ICMP? Choose twoWhich command successfully ping an individual IP address? Answer A, COne Two None Several Which commands should you use to enable Igrp routing? Answer E Answer A, B, C Explanation Answer B, D Answer A, B, CWhat is the bandwidth capacity of an Isdn B channel? Answer a Which statement about Ethernet networks is true? What is the distance limitation for 100BaseT? Which command sets the clock rate to 56 Kbps on serial0? Setup dialogue what do the square bracket indicate? Which command retrieves the configuration file from NVRAM? What is the most common Layer 2 device? SAP Hdlc ARP Novellether Answer a Answer D Answer A, C What are two components of an IPX address? Answer B, C Explanation Answer C, D, E, F Answer F Which two statements are true? Choose two Answer a and dWhat is a backoff on an 802.3 network? What is a key use of a device hardware address? 16,382 65,534 Session Network Transport Maintenance 640 Answer A, C Explanation What are the characteristics of UDP? MAC LLC SAP LCP Tab Ctrl R Spacebar Right Arrow PPP Lapd Isdn Hdlc What does the command show access-list 101 list? Which two commands show your access lists? Choose twoAnswer B, C IP and IPX IP and PPP PPP and Sdlc PPP and Hdlc 640 Answer C, D, E Explanation What are two functions of Icmp protocol? Choose TwoAnswer D, E 172.37.2.55 to What does the term ‘Base’ refer to in 100BaseT? Click the task button & Place the encapsulation Answer Explanation IP-Space enable When you issue the command show version, your router returns From where does the router boot?101 What is the most common mail to device? 103 104 105 106 Which statement about Ethernet switches is true? 108 109 110 111 Answer A, B, F 113 You just entered the following command Which operation is most likely to follow?115 Answer A, B, C, D What is back off on an 802.3 network? 118 Which command displays access list 111? Answer B, E120 121 122 123 124 125 126 Answer E, F, G 128 Answer A, D Explanation 130 What is an advantage of local area network LAN segmentation? What are the generic parts of a network layer address?132 133 134 135 136 How does a bridge function? 138 What are two purposes for using switches? Choose two What is an example of a valid MAC address? 141 Which two physical interfaces does PPP support? Choose two Answers C, D143 144 145 146 147 148 149 What is the purpose of ISL and 802.lq frame tagging? 151 152 Which of the following describes isdn bri servie? 154 Answer B What do you use for loop avoidance? Choose two 156 Answer B Diagram 158 Answer A, B, E Identify the effect of Ctrl-Z? 160 161 162 163 Answer a How do you change the Console password to cisco? 165 166 167 Answer D Q299 Answer C 301Answer D 302 Answer C 303Answer a 304 Answer B, C 307 Answer D 309 What is the purpose of DLCIs in Frame Relay? Answer B 310172 173 Answer C 318 175 176 177 178 179 180 Q327 Answer Unknown 328 Answer Unknown
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