单选题A layer 3 switch can move packets between subnets based on which of the following criteria?（）A 802.1q tagB PortC ApplicationD IP address

第1题：

第2题：

Which of the following is a characteristic of a data center core？（）

• A、 Server-to-server traffic always remains in the core layer.
• B、 The recommended practice is for the core infrastructure to be in Layer 3.
• C、 The boundary between Layer 2 and Layer 3 should be implemented in the aggregation layer.
• D、 The Cisco Express Forwarding hashing algorithm is the default， based on the IP address andLayer 4 port.
• E、 Core layer should run BGP along with an IGP because iBGP has a lower administrativedistance than any IGP.

第3题：

Assuming that an IP packet is sent from a source address in VLAN1 to a destination address in VLAN2 through a layer-3 switch, which part of the packet will be changed?（）

• A、Layer 2 TTL
• B、Layer 3 TTL
• C、Layer 3 source address
• D、Layer 3 destination address

第4题：

You work as a network technician. Your boss is interested in the QoS technology in the context ofvideo traffic. What can be said of application of this technology in this type of network？（）

• A、The access layer is the initial point at which traffic enters the network. Traffic is marked （orremarked） at Layers 2 and 3 by the access switch as it enters the network， or is "trusted" that it isentering the network with the appropriate tag
• B、No traffic marking occurs at the core layer. Layer 2/3 QoS tags are trusted from distributionlayer switches and used to prioritize and queue the traffic as it traverses the core
• C、Traffic inbound from the access layer to the distribution layer can be trusted or reset dependingupon the ability of the access layer switches. Priority access into the core is provided based onLayer 3 QoS tags
• D、IP precedence， DSCP， QoS group， IP address， and ingress interface are Layer 2 characteristics that are set by the access layer as it passes traffic to the distribution layer. Thedistribution layer， once it has made a switching decision to the core layer， strips these off
• E、MAC address， Multiprotocol Label Switching （MPLS）； the ATM cell loss priority （CLP） bit， theFrame Relay discard eligible （DE） bit， and ingress interface are established by the voicesubmodule （distribution layer） as traffic passes to the core layer
• F、The distribution layer inspects a frame to see if it has exceeded a predefined rate of trafficwithin a certain time frame， which is typically a fixed number internal to the switch. If a frame isdetermined to be in excess of the predefined rate limit， the CoS value can be marked up in a waythat results in the packet being dropped

第5题：

Which JUNOS software feature allows a user to define specific next-hop values for IP packets based on the source IP address of that packet？（）

• A、MPLS
• B、Load Balancing
• C、Class Based Forwarding
• D、Filter Based Forwarding

第6题：

A switch port on TK1 is being configured to support 802.1Q trunking.  Which of the following are true about 802.1Q trunking？（）

• A、Both switches must be in the same VTP domain.
• B、The encapsulation type of both ends of the trunk does not have to match.
• C、The native VLAN on both ends of the trunk must be VLAN 1.
• D、802.1Q trunking can only be configured on a Layer 2 port.
• E、In 802.1Q trunking， all VLAN packets are tagged on the trunk link， except the native VLAN.

第7题：

A layer 3 switch can move packets between subnets based on which of the following criteria?（）

• A、802.1q tag
• B、Port
• C、Application
• D、IP address

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第13题：

Which three of the following descriptions are true about the firewall modes？ （）

• A、 Transparent mode is layer 2.
• B、 Routed mode is layer 3.
• C、 Routed mode has 1 IP address.
• D、 Transparent mode has 1 IP address.

第14题：

Why would a network administrator configure port security on a switch?（）

• A、to prevent unauthorized Telnet access to a switch port
• B、to limit the number of Layer 2 broadcasts on a particular switch port
• C、to prevent unauthorized hosts from accessing the LAN
• D、to protect the IP and MAC address of the switch and associated ports
• E、to block unauthorized access to the switch management interfaces over common TCP ports

第15题：

When policy - based routing (PBR) is being configured, which three criteria can the set command specify?（）

• A、all interfaces in the path toward the destination
• B、all networks in the path toward the destination
• C、adjacent next hop router in the path toward the destination
• D、all routers in the path toward the destination
• E、all interfaces through which the packets can be routed
• F、type of service and precedence in the IP packets

第16题：

When configuring a routed port on a Cisco multilayer switch， which of these is a required configuration task that you must perform to enable that port to function as a routed port？ （）

• A、Enable the switch to participate in routing updates from external devices with the router command in global configuration mode.
• B、Enter the no switchport command to disable Layer 2 functionality at the interface level.
• C、Each port participating in routing of Layer 3 packets must have an IP routing protocol assigned on aperinterface level.
• D、Routing is enabled by default on a multilayer switch， so the port can become a Layer 3 routing interface by assigning the appropriate IP address and subnet information.

第17题：

Which two of these are characteristics of MPLS VPNs？ （）

• A、 Layer 3 MPLS VPNs can forward only IP packets
• B、 Layer 2 MPLS VPNs can forward any network protocol
• C、 MPL S label paths are automatically formed based on Layer 2 frames
• D、 Layer 3 MPLS VPNs can forward any network protocol based on Layer 2 frames
• E、 In Layer 2 MPLS VPNS， the service provider controls the customer Layer 3 policies

第18题：

Which of the following devices is used to move frames between a source and destination basedon a MAC address?（）

• A、Repeater
• B、Hub
• C、Router
• D、Switch

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