Review Questions

1.	Which of the following describes isochronous data transfer most accurately? Time sensitive Delay sensitive Reliable Connection oriented
2.	Which of the following describes SLB most accurately? An alternative to HSRP A protocol allowing server load sharing A server redundancy protocol An alternative to switching
3.	Which of the following best describes a best efforts network? Unreliable Guaranteed Connectionless Streaming
4.	Which of the following best describes jitter? Packets arriving with variations in delay Packets arriving later than expected Packets arriving all at once Packets not arriving at all
5.	Which of the following best describes TOS (Type of Service)? TOS is the classification of different IP streams. TOS is a field in the IP header that can be used to classify packets. TOS is applied by DiffServe routers to forward packets. TOS applies only to IPv6.
6.	Which of the following best describes DiffServe? Packets marked and forwarded by each DiffServe router Packets forwarded by each DiffServe router using per-hop forwarding according to TOS Packets following a predetermined path through the DiffServe cloud Packets forwarded using DiffServe parameters
7.	Which of the following might cause variable delay in packet forwarding? (Choose all that apply.) Congested switches First in, first out queuing Varying frame sizes in the switch output buffers Unstable network topology
8.	Which protocol defines Type of Service at the Data Link layer? 802.1D 802.1Q DiffServe 802.1p
9.	What queuing mechanisms are supported by the 2950 switches, running standard edition IOS software? (Choose all that apply.) Custom Queuing Low Latency Priority Queuing Weighted Round Robin Queuing Strict Priority Queuing First in, first out queuing
10.	What is a policy-map used for? To set the different classes of service To determine which traffic is to be matched to specific criteria to be set for incoming traffic To determine the classification criteria to be set for incoming traffic To define the match criteria when classifying traffic
11.	What is a class-map used for? To set the different classes of service To define the match criteria when classifying traffic To determine which traffic is to be matched to specific criteria to be set for incoming traffic To determine the classification criteria to be set for incoming traffic
12.	Which of the following describes GLBP most accurately? An extension to HSRP An alternative to HSRP A replacement for HSRP A firewall load balancing protocol
13.	If a show port capabilities command on a 4000 series router tells you that a port is type 2q1t, what does that mean? The port has two configurable queues, with one drop threshold. The port has one configurable queue with two drop thresholds. The port has the option of one or two configurable queues. The port has two queues but a single timer.
14.	What queue types are supported on the 2950 switch? One normal priority and two configurable high priority One normal priority and four configurable high priority One normal priority and one configurable high priority One normal priority or our configurable high priority
15.	Which of the following services could be described as supporting transparent Ethernet LANs? (Choose all that apply.) Ethernet over Fiber Ethernet over ADSL Ethernet over DWDM Ethernet over IP networks Ethernet over wireless
16.	Which of the following best describes Weighted Round Robin Queuing? A queuing mechanism where each queue is the same length and is serviced in turn A queuing mechanism where each queue is of configurable length and is serviced in turn A queuing mechanism where each queue is of different length and is serviced in priority of size A queuing mechanism where each queue is of configurable length and is serviced using strict priority
17.	What is the default QoS configuration on a 3550 switch? QoS is globally disabled, so no classification occurs. QoS is globally enabled, so a default classification is applied. QoS is globally disabled; packets arriving with the DSCP set will be discarded. QoS is globally disabled; packets arriving with the DSCP set will be forwarded, but error messages will be created.
18.	How does auto-QoS discover whether a Cisco IP telephone is connected to a switch port? Cisco proprietary IP hellos Cisco Discovery Protocol (CDP) It does not discover; you have to manually configure the interface. Enhanced Cisco Discovery Protocol (ECDP)
19.	Which of the following best describes the preempt function in HSRP? Can take over when active fails Works only in groups of two routers Will not release to higher priority routers Will take over from lower-priority active routers
20.	Which of the following interface commands sets the standby IP address on an interface to 192.168.1.200? standby ip address 192.168.1.200 hsrp address 192.168.1.200 standby ip 192.168.1.200 ip address 192.168.1.200 standby

Answers

1.	A The word isochronous comes from the Greek words iso (equal) and chrono (time). So isochronous traffic is time sensitive.
2.	B SLB stands for Server Load Balancing, and although some redundancy may be configured, it is designed to load-balance connections across more than one server.
3.	A Best efforts networks deliver datagrams as best they can. Without any additional features, such as acknowledgments and requests for retransmission, they are regularly termed unreliable.
4.	A Jitter is the term used to describe the effect caused by successive packets arriving with different delay times.
5.	B Inside IPv4, the limited provisions for prioritization are encoded in the 3 bits entitled Type of Service.
6.	B Differentiated Services (DiffServe) provides no integrated capabilities. Each DiffServe router must be configured to forward data using local priorities.
7.	A, B, C, D In a best efforts network, almost anything can cause delay to occur, and to occur variably.
8.	D Inside the 802.1Q standard for VLAN definition, 3 bits are allocated to the priority of the Ethernet frame. These 3 bits are fully defined inside 802.1p.
9.	C, D, E Custom Queuing and Low Latency Priority Queuing are usually associated with layer 3 functionality in the IOS.
10.	C Class-maps define the criteria for matching, and policy-maps define the classification for setting.
11.	B Class-maps define the criteria for matching , and policy-maps define the classification for setting.
12.	B Gateway Load Balancing Protocol operates in almost exactly the same way as HSRP, but with the added advantage of utilizing standby routers that HSRP does not utilize.
13.	A The queue type on a port is fixed in the hardware, and the show port capabilities command allows you to determine what you have.
14.	B Even so, the queues have some independence. You can just use the normal priority queue and FIFO, or you can enable QoS to get access to the other queues.
15.	A, C, D Although the technology for extending Ethernet is constantly under review, only Ethernet over Fiber, Ethernet over DWDM, and Ethernet over IP networks are correct.
16.	B Round robin queuing means servicing each queue in turn. Weighted means configuring the length of each queue to modify the fairness of the traffic distribution.
17.	A By default, QoS is disabled on all Cisco switches.
18.	B The proprietary Cisco Discovery Protocol multicasts machine properties based on a (configurable) timer. Cisco IP telephones therefore announce to Cisco switches that they are connected using a CDP hello.
19.	D Preemption allows HSRP routers to take over at any time if they have the highest configured priority in a group.
20.	C The interface command standby ip ip_address sets the standby IP address.