Regarding PAR (Positive Acknowledgement and Re－transmission), which of the answer choices below are correct?()A. The source device will only retransmit lost packets on the request of the destination device.B. The source device starts a timer when it sends
题目
A. The source device will only retransmit lost packets on the request of the destination device.
B. The source device starts a timer when it sends a segment and retransmits if an acknowledgment is not received before the timer expires.
C. The destination device acknowledges receipt of a segment by sending a packet with a new sequence number and the ACK bit sent.
D. The destination device acknowledges receipt of a segment by sending a packet that indicates the next sequence number it expects.
E. If the destination device does not receive a segment, all segments are retransmitted.
F. The source device keeps a record of all segments sent and expects and acknowledgment of each.
相似考题
更多“Regarding PAR (Positive Acknowledgement and Re－transmission), which of the answer choices below are correct?() ”相关问题
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第1题：
Which of following VLAN frame. encapsulation types are configurable on a Cisco switch? (Select two answer choices.)
A. VTP
B. 802.1Q
C. LLC
D. ISL
E. CDP
F. PAP
正确答案：BD
B,D 解析：Explanation:
ISL and 802.1Q are the two trunking encapsulations that can be configured on a Cisco switch. ISL is Cisco proprietary and 802.1Q is the IEEE standard method.
Incorrect Answers:
A. VTP is the VLAN Trunking Protocol, which is used to carry VLAN information across the trunks. The question is asking for the encapsulation options for the trunk, which will be used by VTP.
C. LLC is the Logical Link Control, which is a sub-layer of the data link layer.
E. CDP is the Cisco Discovery Protocol, which is used by Cisco devices to discover information on neighboring Cisco devices.
F. PAP is the Password Authentication Protocol, which is used as an authentication mechanism on PPP links.
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第2题：
Which encapsulation types are configurable on a Cisco switch for a trunk? (Select two answer choices)
A. VTP
B. ISL
C. CDP
D. 802.1Q
E. 802.1p
F. LLC
G. IETF
正确答案：BD
B,D 解析：Explanation:
Trunks are used to carry traffic belonging to multiple VLANs between devices over the same link. A device can determine which VLAN the traffic belongs to by its VLAN identifier. The VLAN identifier is a tag that is encapsulated with the data. ISL and 802.1q are two types of encapsulations used to carry data from multiple VLANs over trunk links.
ISL is a Cisco proprietary protocol for interconnecting multiple switches and maintaining VLAN information as traffic goes between switches. ISL provides VLAN trunking capabilities while maintaining full wire speed performance on Ethernet links in full-duplex or half-duplex mode. ISL operates in a point-to-point environment and will support up to 1000 VLANs.
In ISL, the original frame. is encapsulated and an additional header is added before the frame. is carried over a trunk link. At the receiving end, the header is removed and the frame. is forwarded to the assigned VLAN. .ISL uses Per VLAN Spanning Tree (PVST) which runs one instance of Spanning Tree Protocol (STP) per VLAN.
PVST allows for optimal root switch placement for each VLAN and supports load balancing of VLANs over multiple trunk links. 802.1Q is the IEEE standard for tagging frames on a trunk and supports up to 4096 VLANs. In 802.1Q, the trunking device inserts a four-byte tag into the original frame. and re-computes the Frame. Check Sequence (FCS) before sending the frame. over the trunk link. At the receiving end, the tag is removed and the frame. is forwarded to the assigned VLAN. 802.1Q does not tag frames on the native VLAN.
It tags all other frames transmitted and received on the trunk. While configuring a 802.1 trunk, you must make sure that the same native VLAN is configured on both sides of the trunk. IEEE 802.1Q defines a single instance of spanning tree running on the native VLAN for all the VLANs in the network which is called Mono Spanning Tree (MST). This lacks the flexibility and load balancing capability of PVST available with ISL. However, PVST+ offers the capability to retain multiple Spanning Tree topologies with 802.1Q trunking.
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第3题：
Which of the following answer choices is an additional parameter which must be supplied before the IGRP routing process can initialize?()A. Connected subnet numbers
B. Register administrative subnet masks
C. IP address mask
D. Autonomous system number
E. Metric weights
参考答案：D
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第4题：
The usual way to ensure reliable delivery is to provide the (71) with some feedback about what is happening at the other end of the line. Typically, the protocol calls for the receiver to send back special (72) flame bearing positive or negative (73) about the incoming frames. If the sender receives a positive acknowledgement about a frame, it knows the frame. has arrived safely. On the other hand, a negative acknowledgement means that' something has gone wrong, and the frame. must be transmitted again.
An additional complication comes from the possibility that hardware troubles may cause a flame to (74) completely. In this case, the receiver will not react at all, since it has no any reason to react. It should be clear that a protocol in which the sender transmits a frame. and then waits for an acknowledgement, positive or negative, will hang forever if a frame. is ever lost due to, for example, (75) hardware.
A．receiver
B．controller
C．sender
D．customer
正确答案：C
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第5题：
After replacing the NIC card of a PC on the LAN, your Cisco switch shows a new MAC address is attached to that port. Which of the following answer choices below correctly describe a MAC address?（）
- A、It is a globally unique IP address.
- B、It is a globally unique 48 bit address
- C、It is provided by the manufacturer of the NIC.
- D、It is used as part of the IPX/SPX configuration.
- E、It is a logical address.
正确答案:B,C -
第6题：
Which of the following answer choices is an additional parameter which must be supplied before the IGRP routing process can initialize?（）
- A、Connected subnet numbers
- B、Register administrative subnet masks
- C、IP address mask
- D、Autonomous system number
- E、Metric weights
正确答案:D -
第7题：
Which one of the following answer choices below is true regarding the OSPF topology database?（）
- A、All entries in the topology database will be included on each router.
- B、All routers in the same OSPF area will have one topology database.
- C、The Dijkstra algorithm is used in the creation of the topology database.
- D、LSA packets are used to update and maintain the topology database.
正确答案:D -
第8题：
A customer purchases a virtual media key on a x3650 M3. They ask where to install the key. Which of the following provides the correct answer？（）
- A、Problem Determination and Service Guide
- B、xRef
- C、ServerGuide Hardware Reference
- D、COG
正确答案:A -
第9题：
多选题Which of the following are factors of 240? (Indicate all of the answer choices that apply.)A6
B9
C12
D20
E36
F45
正确答案： A,D解析：
将240分解质因子得到，240 = 24 × 10 = 6 × 4 × 10=2 × 3 × 2 × 2 × 5× 2，所以本题选择ACD三项。 -
第10题：
单选题Which of the following answer is correct to express the value 8 in octal number？（）A010
B0x10
C08
D0x8
正确答案： A解析： 八进制值以0开头，以0x开头的为十六进制值，八进制中不能出现数字8，最大只有7。 -
第11题：
单选题Which of the following answer choices is an additional parameter which must be supplied before the IGRP routing process can initialize?（）AConnected subnet numbers
BRegister administrative subnet masks
CIP address mask
DAutonomous system number
EMetric weights
正确答案： B解析： 暂无解析 -
第12题：
多选题Which of the following points are on the straight line through (1, 4) and (3, -2)? (Indicate all of the answer choices that apply.)A(2, 1)
B(0, 5)
C(4, -5)
D(-1, 8)
E(15, 5)
正确答案： E,B解析：
通过点(1, 4)和(3, -2)的直线为y - 4=-3(x- 1)，故可知AC在直线上，故本题选择AC两项。 -
第13题：
The price at which a stock can be sold depends upon a number of factors. Which statement below is not one of those factors ().A.the financial condition, earnings record, and dividend record of the corporation
B.investor expectations of the corporations earning power
C.how high the par value
D.general business and economic conditions and prospects
正确答案：C
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第14题：
After replacing the NIC card of a PC on the LAN, your Cisco switch shows a new MAC address is attached to that port. Which of the following answer choices below correctly describe a MAC address?()A. It is a globally unique IP address.
B. It is a globally unique 48 bit address
C. It is provided by the manufacturer of the NIC.
D. It is used as part of the IPX/SPX configuration.
E. It is a logical address.
参考答案：B, C
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第15题：
● The usual way to ensure reliable delivery is to provide the （71） with some feedback about what is happening at the other end of the line. Typically, the protocol calls for the receiver to send back special （72） frame. bearing positive or negative （73） about the incoming frames. If the sender receives a positive acknowledgement about a frame, it knows the frame. has arrived safely. On the other hand, a negative acknowledgement means that something has gone wrong, and the frame. must be transmitted again. An additional complication comes from the possibility that hardware troubles may cause a
frame. to （74） completely. In this case, the receiver will not react at all, since it has no any reason to react. It should be clear that a protocol in which the sender transmits a frame. and then waits for an acknowledgement, positive or negative, will hang forever if a frame. is ever lost due to, for example, （75） hardware.
（71）
A. receiver
B. controller
C. sender
D. customer
（72）
A. data
B. control
C. request
D. session
（73）
A. application
B. connection
C. stream
D. acknowledgement
（74）
A. vanish
B. vary
C. appear
D. incline
（75）
A. acting
B. working
C. malfunctioning
D. functioning
正确答案：C,B,D,A,C
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第16题：
Most economic data,____regarding hiring is positive.A.completely
B.exclusively
C.particularly
D.specifically答案：D解析：本题考查词语辨析。题目意为：“大部分经济数据明确显示就业率正在趋好发展。” A项completely“完全地，彻底地”。B项 exclusively“唯一地，专有地，排外地”。C项particularly “特别地，独特地”。D项specifically“明确地，具体地”。
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第17题：
Which of the following is correct regarding full-state backups?（）
- A、used for either a single or dual UCS catastrophic failure
- B、can be restored with no special requirements
- C、stored as gzipped tarball
- D、easy to modify as needed
正确答案:C -
第18题：
Which of the following answer is correct to express the value 8 in octal number？（）
- A、 010
- B、 0x10
- C、 08
- D、 0x8
正确答案:A -
第19题：
Regarding PAR (Positive Acknowledgement and Re-transmission), which of the answer choices below are correct?（）
- A、The source device will only retransmit lost packets on the request of the destination device.
- B、The source device starts a timer when it sends a segment and retransmits if an acknowledgment is not received before the timer expires.
- C、The destination device acknowledges receipt of a segment by sending a packet with a new sequence number and the ACK bit sent.
- D、The destination device acknowledges receipt of a segment by sending a packet that indicates the next sequence number it expects.
- E、If the destination device does not receive a segment, all segments are retransmitted.
- F、The source device keeps a record of all segments sent and expects and acknowledgment of each.
正确答案:B,D,F -
第20题：
Which two statements regarding JUNOS architecture are correct？（）
- A、The Routing Engine handles all exception traffic.
- B、The Routing Engine synchronizes the route table with the PFE
- C、The Routing Engine is hot-pluggable.
- D、The Routing Engine controls the PFE
正确答案:C,D -
第21题：
多选题Triangle PQR is isosceles and ∠PQR measures 50°. Which of the following could be the measure of ∠PRQ? (Indicate all of the answer choices that apply.)A60°
B65°
C80°
D100°
E130°
正确答案： D,E解析：
因为⊿PQR为等腰三角形，所以当∠PQR为顶角时，∠PRQ=65°；当∠PQR为底角时，∠PRQ=80°，故本题选择BC。 -
第22题：
多选题After replacing the NIC card of a PC on the LAN, your Cisco switch shows a new MAC address is attached to that port. Which of the following answer choices below correctly describe a MAC address?（）AIt is a globally unique IP address.
BIt is a globally unique 48 bit address
CIt is provided by the manufacturer of the NIC.
DIt is used as part of the IPX/SPX configuration.
EIt is a logical address.
正确答案： E,D解析： 暂无解析 -
第23题：
多选题Which of the following answer choices are correct characteristics of named access list?（）AYou can delete individual statements in a named access list
BNamed access lists require a numbered range from 1000 to 1099.
CNamed access lists must be specified as standard or extended.
DYou can use the ip access-list command to create named access lists.
EYou cannot delete individual statements in a named access list.
FYou can use the ip name-group command to apply named access lists.
正确答案： F,C解析： 暂无解析 -
第24题：
单选题Which one of the following answer choices below is true regarding the OSPF topology database?（）AAll entries in the topology database will be included on each router.
BAll routers in the same OSPF area will have one topology database.
CThe Dijkstra algorithm is used in the creation of the topology database.
DLSA packets are used to update and maintain the topology database.
正确答案： D解析： 暂无解析