单选题Distribution layer: This layer includes LAN-based routers and layer 3 switches . When is a first-hop redundancy protocol needed in the distribution layer?（）A OSPF is not supported by the designB HSRP is not supported by the designC preempt tuning of th

A. when HSRP is not supported by the design

B. when multiple vendor devices need to be supported

C. when preempt tuning of the default gateway is needed

D. when a robust method of backing up the default gateway is needed

E. when the design implements Layer 2 between the access switch and the distribution switch

F. when the design implements Layer 3 between the access switch and the distribution switch

A. to a core switch running Cisco NSF and SSO from redundant distribution switches connected with a Layer 2 link

B. to a core switch running Cisco NSF and SSO from redundant distribution switches connected with a Layer 3 link

C. to two core switches from redundant distribution switches connected with a Layer 2 link

D. to two core switches from redundant distribution switches connected with a Layer 3 link

E. to two core switches running Cisco NSF and SSO from two redundant distribution switches running Cisco NSF and SSO

TCP functions at the Open System Interconnection(OSI)(61)layer, or Layer 4. Its chief responsibility is to ensure(62)end-to-end connectivity. IP, located one layer down, at the OSI network layer, or Layer 3, communicates the addresses of each(63)sender and receiver to the routers along the way. Routers and Layer 3 switches can read IP and other Layer 3(64). This information, combined with routing tables and other network intelligence, is all it takes to get(65)the room or around the world via TCP/IP.

A．transpose

B．translate

C．transmit

D．transport

A. use a Layer 2 link between distribution switches

B. use a Layer 3 link between distribution switches

C. use a redundant link to the core

D. use a Layer 3 link between distribution switches with route summarization

A. If no core layer is deployed, the design will be easier to scale.

B. If no core layer is deployed, there will be fewer cabling requirements.

C. If no core layer is deployed, the distribution switches should not be fully meshed.

D. A dedicated campus core layer is not needed for connecting fewer than five buildings.

E. A dedicated campus core layer should be deployed for connecting three or more buildings.

A. map the Layer 2 VLAN number to the Layer 3 subnet

B. control route propagation to edge switches using distribute lists

C. use a Layer 2 distribution interconnection link with HSRP or GLBP

D. use a Layer 3 distribution interconnection link with HSRP or GLBP

E. use equal-cost Layer 3 load balancing on all links to limit the scope of queries in EIGRP

A. The core layer should use default Layer 3 hash information.

B. The core layer should use default Layer 4 hash information.

C. The distribution layer should use default Layer 3 hash information.

D. The distribution layer should use default Layer 4 hash information.

E. The core layer should use Layer 3 and Layer 4 information as input to the Cisco Expressing Forwarding hashing algorithm.

F. The distribution layer should use Layer 3 and Layer 4 information as input into the Cisco Expressing Forwarding hashing algorithm.

Routers perform the decision process that selects what path a packet takes. These （ ） layer devices participate it the collection and distribution of network-layer information, and perform Layer 3 switching based on the contents of the network layer （ ） of each packet. You can connect the routers directly by point-to-point （ ） or local-area networks, or you can connect them by LAN or WAN switches. These Layer 2 switches unfortunately do not have the capability to hold Layer 3 （ ） information or to select the path taken by a packet through analysis of its Layer 3 destination address. Thus, Layer 2 switches be involved in the Layer 3 packet （ ） decision process.

A.application B. network C.physical D.link A.header B.connection C.protocol D.data A.medium B.links C.switches D.carriers A.network B.links C.protocol D.routing A.switching B.processing C.forwarding D.connecting

A. OSPF is not supported by the design

B. HSRP is not supported by the design

C. preempt tuning of the default gateway is needed

D. the design implements Layer 3 between the access switch and the distribution switch