Final Review 2

Refer to the exhibit. What will router R1 do with a packet that has a destination IPv6 address of 2001:db8:cafe:5::1?

• forward the packet out GigabitEthernet0/0

• drop the packet

• forward the packet out GigabitEthernet0/1

• forward the packet out Serial0/0/0

Answer explanation

The route ::/0 is the compressed form of the 0000:0000:0000:0000:0000:0000:0000:0000/0 default route. The default route is used if a more specific route is not found in the routing table.

What is an advantage of PVST+?

• PVST+ optimizes performance on the network through autoselection of the root bridge.

• PVST+ reduces bandwidth consumption compared to traditional implementations of STP that use CST.

• PVST+ requires fewer CPU cycles for all the switches in the network.

• PVST+ optimizes performance on the network through load sharing.

Answer explanation

PVST+ results in optimum load balancing. However, this is accomplished by manually configuring switches to be elected as root bridges for different VLANs on the network. The root bridges are not automatically selected. Furthermore, having spanning-tree instances for each VLAN actually consumes more bandwidth and it increases the CPU cycles for all the switches in the network.

What protocol or technology uses a standby router to assume packet-forwarding responsibility if the active router fails?

• EtherChannel

• DTP

• HSRP

• VTP

What action takes place when the source MAC address of a frame entering a switch is in the MAC address table?

• The switch forwards the frame out of the specified port.

• The switch updates the refresh timer for the entry.

• The switch replaces the old entry and uses the more current port.

• The switch adds a MAC address table entry for the destination MAC address and the egress port.

A small publishing company has a network design such that when a broadcast is sent on the LAN, 200 devices receive the transmitted broadcast. How can the network administrator reduce the number of devices that receive broadcast traffic?

• Add more switches so that fewer devices are on a particular switch.

• Replace the switches with switches that have more ports per switch. This will allow more devices on a particular switch.

• Segment the LAN into smaller LANs and route between them.

• Replace at least half of the switches with hubs to reduce the size of the broadcast domain.

Answer explanation

By dividing the one big network into two smaller network, the network administrator has created two smaller broadcast domains. When a broadcast is sent on the network now, the broadcast will only be sent to the devices on the same Ethernet LAN. The other LAN will not receive the broadcast.

What defines a host route on a Cisco router?

• The link-local address is added automatically to the routing table as an IPv6 host route.

• An IPv4 static host route configuration uses a destination IP address of a specific device and a /32 subnet mask.

• A host route is designated with a C in the routing table.

• A static IPv6 host route must include the interface type and the interface number of the next hop router.

Which mitigation technique would prevent rogue servers from providing false IPv6 configuration parameters to clients?

• enabling DHCPv6 Guard

• enabling RA Guard

• implementing port security on edge ports

• disabling CDP on edge ports

Answer explanation

DHCPv6 Guard is a feature designed to ensure that rogue DHCPv6 servers are not able to hand out addresses to clients, redirect client traffic, or starve out the DHCPv6 server and cause a DoS attack. DHCPv6 Guard requires a policy to be configured in DHCP Guard configuration mode, and DHCPv6 Guard is enabled on an interface-by-interface basis.

While attending a conference, participants are using laptops for network connectivity. When a guest speaker attempts to connect to the network, the laptop fails to display any available wireless networks. The access point must be operating in which mode?

• mixed

• passive

• active

• open

Answer explanation

Active is a mode used to configure an access point so that clients must know the SSID to connect to the access point. APs and wireless routers can operate in a mixed mode meaning that that multiple wireless standards are supported. Open is an authentication mode for an access point that has no impact on the listing of available wireless networks for a client. When an access point is configured in passive mode, the SSID is broadcast so that the name of wireless network will appear in the listing of available networks for clients.

Which three components are combined to form a bridge ID?

• extended system ID

• bridge priority

• MAC address

• port ID

• cost

Answer explanation

The three components that are combined to form a bridge ID are bridge priority, extended system ID, and MAC address.

A PC has sent an RS message to an IPv6 router attached to the same network. Which two pieces of information will the router send to the client? (Choose two.)

• prefix length

• subnet mask in dotted decimal notation

• domain name

• administrative distance

• prefix

Answer explanation

Router is part of the IPv6 all-routers group and received the RS message. It generates an RA containing the local network prefix and prefix length /64