Cisco

Cisco 642-813

642-813 Implementing Cisco IP Switched Networks (SWITCH)

Practice Test
Version

Cisco 642-813: Practice Exam QUESTION NO: 1 Company uses layer 3 switches in the Core of their network. Which method of Layer 3 switching uses a forwarding information base (FIB)? A. Topology-based switching B. Demand-based switching C. Route caching D. Flow-based switching E. None of the otheralternatives apply Answer: A Explanation: The Layer 3 engine (essentially a router) maintains routing information, whether from static routes or dynamic routing protocols. Basically, the routing table is reformatted into an ordered list with the most specific route first, for each IP destination subnet in the table. The new format is called a Forwarding Information Base (FIB) and contains routingor forwarding information that the network prefix can reference. In other words, a route to 10.1.0.0/16 might be contained in the FIB, along with routes to 10.1.1.0/24 and 10.1.1.128/25, if those exist. Notice that these examples are increasingly more specific subnets. In the FIB, these would be ordered with the most specific, or longest match, first, followed by less specific subnets. When theswitch receives a packet, it can easily examine the destination address and find the longest match entry in the FIB. The FIB also contains the nexthop address for each entry. When a longest match entry is found in the FIB, the Layer 3 next-hop address is found, too.

QUESTION NO: 2

You need to design the VLAN scheme for the Company network. Which two statements are true about best practices inVLAN design? (Select two) A. Routing should occur at the access layer ifvoice VLANs are utilized. Otherwise, routing should occur at the distribution layer. B. Routing should always be performed at the distribution layer. C. VLANs should be localized to a switch. D. VLANs should be localized to a single switch unlessvoice VLANs are being utilized. E. Routing should not be performed between VLANslocated on separate switches. Answer: B,C Explanation: In the distribution layer, uplinks from all access layer devices are aggregated, or come together. The distribution layer switches must be capable of processing the total volume of traffic from all "Pass Any Exam. Any Time." - www.actualtests.com 2

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Cisco 642-813: Practice Exam the connected devices.These switches should have a port density of high-speed links to support the collection of access layer switches. VLANs and broadcast domains converge at the distribution layer, requiring routing, filtering, and security. The switches at this layer must be capable of performing multilayer switching with high throughput. Only certain Catalyst switch models can provide multilayer switching; be sureto understand which ones can do this. A switched environment offers the technology to overcome flat network limitations. Switched networks can be subdivided into VLANs. By definition, a VLAN is a single broadcast domain. All devices connected to the VLAN receive broadcasts from other VLAN members. However, devices connected to a different VLAN will not receive those same broadcasts. (Naturally,VLAN members also receive unicast packets directed toward them from other VLAN members.) A VLAN consists of defined members communicating as a logical network segment. In contrast, a physical segment consists of devices that must be connected to a physical cable segment. A VLAN can have connected members located anywhere in the campus network, as long as VLAN connectivity is provided between allmembers. Layer 2 switches are configured with a VLAN mapping and provide the logical connectivity between the VLAN members.

QUESTION NO: 3

Refer to the exhibit. On the basis of the information provided in the exhibit, which two sets of procedures are best practices for Layer 2 and 3 failover alignment? (Choose two.)

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