QUESTION NO: 1
Which of these correctly identifies difference between the way BPDUs are handled by 802.1w and 802.1D?
A. 802.1 D bridges do not relay
B. 802.1w bridges do not relay BPDUs
C. 802.1D bridges only relay BPDUs received from the root
D. 802.1w bridges only relay BPDUs received from the root.
Answer: C

Explanation:

A bridge sends a BPDU frame using the unique MAC address of the port itself as a source address, and a destination address of the STP multicast address 01:80:C2:00:00:00.There are three types of BPDUs:Configuration BPDU (CBPDU), used for Spanning Tree computation Topology Change Notification (TCN) BPDU, used to announce changes in the network topology Topology Change Notification Acknowledgment (TCA) BPDU are Sent Every Hello-Time BPDU are sent every hello-time, and not simply relayed anymore. With 802.1D, a non-root bridge only generates BPDUs when it receives one on the root port. In fact, a bridge relays BPDUs more than it actually generates them. This is not the case with 802.1w. A bridge now sends a BPDU with its current information every <hello-time> seconds (2 by default), even if it does not receive any from the root bridge.
Reference
http://www.cisco.com/en/US/tech/tk389/tk621/technologies_white_paper09186a0080094cfa.shtml#topic4

QUESTION NO: 2

In Frame Relay, FECN messages indicating congestion are sent or received by which of
following?
A. Sent by the destination
B. Received by the sender
C. Received by the destination
D. Sent by the sender
Answer: C
Explanation:

Congestion control
The Frame Relay network uses a simplified protocol at each switching node. It achieves simplicity by omitting link-by-link flow-control. As a result, the offered load has largely determined the performance of Frame Relay networks. When offered load is high, due to the bursts in some services, temporary overload at some Frame Relay nodes causes a collapse in network throughput. Therefore, frame-relay networks require some effective mechanisms to control the congestion. Congestion control in frame-relay networks includes the following elements:Admission Control provides the principal mechanism used in Frame Relay to ensure the guarantee of resource requirement once accepted. It also serves generally to achieve high network performance. The network decides whether to accept a new connection request, based on the relation of the requested traffic descriptor and the network's residual capacity. The traffic descriptor consists of a set of parameters communicated to the switching nodes at call set-up time or at service-subscription time, and which characterizes the connection's statistical properties.The traffic descriptor consists of three elements Committed Information Rate (CIR) - The average rate (in bit/s) at which the network guarantees to transfer information units over a measurement interval T. This T interval is defined as: T = Bc/CIR.Committed Burst Size (BC) - The maximum number of information units transmittable during the interval T. Excess Burst Size (BE) - The maximum number of uncommitted information units (inbits) that the network will attempt to carry during the interval.Once the network has established a connection, the edge node of the Frame Relay network must monitor the connection's traffic flow to ensure that the actual usage of network resources does not exceed this specification. Frame Relay defines some restrictions on the user's information rate.It allows the network to enforce the end user's information rate and discard information when the subscribed access rate is exceeded.Explicit congestion notification is proposed as the congestion avoidance policy. It tries to keep the network operating at its desired equilibrium point so that a certain Quality of Service (QoS) for the network can be met. To do so, special congestion control bits have been incorporated into the address field of the Frame Relay:FECN and BECN.The basic idea is to avoid data accumulation inside the network.FECN means Forward Explicit Congestion Notification. The FECN bit can be set to 1 to indicate that congestion was experienced in the direction of the frame transmission, so it informs the destination that congestion has occurred. BECN means Backwards Explicit Congestion Notification. The BECN bit can be set to 1 to indicate that congestion was experienced in the network in the direction opposite of the frame transmission, so it informs the sender that congestion has occurred.

QUESTION NO: 3
What does the OSPF command capability vrf-lite achieve?
A. It enables provider edge (PE) specific checks on a router when the OSPF process is associated
with the VRF.
B. It disables provider edge (PE) specific checks on a router when the OSPF process is
associated with the VRF.
C. It enables the exchange of the "VRF-Lite" capability when the OSPF adjacency is formed.
D. It disables the MPLS processing on the OSPF learned routes inside the VRF.
Answer: B

Explanation:
Capability vrf-lite To suppress the Provider Edge (PE) specific checks on a router when the OSPF process is associated with the VRF, use the capability vrf-lite command in router configuration mode. To restore the checks, use the no form of this command. capability vrf-lite no capability vrf-lite Syntax Description.This command has no arguments or keywords.Defaults Disabled. PE specific checks are performed if the process is associated with VRF command modes Prerequisites CEF must be running on the network.
SUMMARY STEPS
1. enable
2. show ip ospf [process-id]
3. configure terminal
4. router ospf process-id [vrf vpn-name]
5. capability vrf-lite
Reference
http://www.cisco.com/en/US/docs/ios/12_0st/12_0st21/feature/guide/ospfvrfl.html

QUESTION NO: 4
Which statement is correct in reference to IPv6 multicast?
A. IPv6 multicast uses Multicast Listener Discovery.
B. The first 8 bits of an IPv6 multicast address are always FF (1111 1111).
C. IPv6 multicast requires MSDP.
D. PIM dense mode is not part of IPv6 multicast.
Answer: A

QUESTION NO: 5
Which two of these are used in the selection of a root bridge in a network utilizing Spanning Tree Protocol IEEE 802.1 D? (Choose two.)
A. Designated Root Cost
B. bridge ID priority
C. max age
D. bridge ID MAC address
E. Designated Root Priority
F. forward delay
Answer: B,D

Explanation:
The root bridge of the spanning tree is the bridge with the smallest (lowest) bridge ID. Each bridge has a unique identifier (ID) and a configurable priority number; the bridge ID contains both numbers. To compare two bridge IDs, the priority is compared first. If two bridges have equal priority, then the MAC addresses are compared. For example, if switches A (MAC=0200.0000.1111) and B (MAC=0200.0000.2222) both have a priority of 10, then switch A will be selected as the root bridge. If the network administrators would like switch B to become the root bridge, they must set its priority to be less than 10.

QUESTION NO: 6
Which three factors have the biggest influence on OSPF scalability? (Choose three.)
A. Flooding paths and redundancy
B. Amount of routing information in the OSPF area or routing domain
C. Number of routers with Cisco Express Forwarding enabled
D. Number of neighbor adjacencies
E. Other routing protocols in use
F. OSPF timer reconstruction negotiation
G. Redistribution with BGP neighbors
H. Redistribution with other IGP routing protocols, such as RIP or EIGRP
Answer: A,B,D