Section 1 – Implement VLAN based solution, given a network design and a set of requirements
QUESTION NO: 6
Two Company switches are connected via a trunk using VTP. Which VTP information does a Catalyst switch advertise on its trunk ports when using VTP? (Select two)
A. STP root status
B. VTP mode
C. Negotiation status
D. Management domain
E. Configuration revision number
Answer: D,E
Explanation:
The role of the VLAN Trunking Protocol (VTP) is to maintain VLAN configuration consistency across the entire network. VTP is a messaging protocol that uses Layer 2 trunk frames to manage the addition, deletion, and renaming of VLANs on a network-wide basis from a centralized switch that is in the VTP server mode. VTP is responsible for synchronizing VLAN information within a VTP domain. This reduces the need to configure the same VLAN information on each switch.
Using VTP, each Catalyst Family Switch advertises the following on its trunk ports: Management domain Configuration revision number Known VLANs and their specific parameters.
QUESTION NO: 7
Switch R1 is configured with VTP. Which two VTP modes will make R1 capable of creating and deleting VLANs on itself? (Select two)
A. Client
B. Server
C. Transparent
D. Pass-through
E. No-negotiate
Answer: B,C
Explanation:
VTP Modes
You can configure a switch to operate in any one of these VTP modes: Server-In VTP server mode, you can create, modify, and delete VLANs and specify other configuration parameters (such as VTP version) for the entire VTP domain. VTP servers advertise their VLAN configuration to other switches in the same VTP domain and synchronize their VLAN configuration with other switches based on advertisements received over trunk links. VTP server is the default mode.
Client-VTP clients behave the same way as VTP servers, but you cannot create, change, or delete VLANs on a VTP client. Transparent-VTP transparent switches do not participate in VTP. A VTP transparent switch does not advertise its VLAN configuration and does not synchronize its VLAN configuration based on received advertisements. However, in VTP version 2, transparent switches do forward VTP advertisements that they receive out their trunk interfaces.
If you configure the switch as VTP transparent, you can create and modify VLANs but the changes affect only the individual switch.
Incorrect Answers:
A: Clients cannot modify, add, or delete any VLAN information.
D: These options are not valid VTP modes.
E: These options are not valid VTP modes.
QUESTION NO: 8
Refer to the exhibit. Switch S2 contains the default configuration. Switches S1 and S3 both have had the command spanning-tree mode rapid-pvst issued on them. What will be the result?
A. IEEE 802.1D and IEEE 802.1w are incompatible. All three switches must use the same standard or no traffic will pass between any of the switches.
B. Switches S1, S2, and S3 will be able to pass traffic between themselves.
C. Switches S1, S2, and S3 will be able to pass traffic between themselves. However, if there is a topology change, Switch S2 will not receive notification of the change.
D. Switches S1 and S3 will be able to exchange traffic but neither will be able to exchange traffic with Switch S2
Answer: B
Explanation:
Cisco Catalyst switches support three types of STPs, which are PVST+, rapid-PVST+ and MST.
PVST+ is based on IEEE802.1D standard and includes Cisco proprietary extensions such as BackboneFast, UplinkFast, and PortFast. Rapid-PVST+ is based on IEEE 802.1w standard and has a faster convergence than 802.1D. RSTP (IEEE 802.1w) natively includes most of the Cisco proprietary enhancements to the 802.1D Spanning Tree, such as BackboneFast and UplinkFast.
Rapid-PVST+ uses the same BPDU format as the 802.1D and it is backward compatible. It is difficult to convert all the switches in the enterprise network at the same time to rapid-PVST+. Because of the backward compatibility, you can convert phase by phase.
QUESTION NO: 9
Which of the following technologies would an Internet Service Provider use to support overlapping customer VLAN ID’s over transparent LAN services?
A. 802.1q tunneling
B. ATM
C. SDH
D. IP Over Optical Networking
E. ISL
Answer: A
Explanation:
Understanding How 802.1Q Tunneling Works :
The 802.1Q tunneling feature supports secure virtual private networks (VPNs). 802.1Q tunneling enables service providers to keep traffic from different customers segregated in the service provider infrastructure while significantly reducing the number of VLANs required to support the VPNs. 802.1Q tunneling allows multiple customer VLANs to be carried by a single VLAN on the Catalyst 6000 family switch without losing their unique VLAN IDs.
When you configure 802.1Q tunneling on the Catalyst 6000 family switch, traffic to be tunneled comes into the switch from an 802.1Q trunk port on a neighboring device and enters the switch through a port configured to support 802.1Q tunneling (a tunnel port). When the tunnel port receives traffic from an 802.1Q trunk port, it does not strip the 802.1Q tags from the frame header but, instead, leaves the 802.1Q tags intact and puts all the received 802.1Q traffic into the VLAN assigned to the tunnel port. The VLAN assigned to the tunnel port then carries the tunneled customer traffic to the other neighboring devices participating in the tunnel port VLAN. When the tunneled traffic is received by an 802.1Q trunk port on a neighboring device, the 802.1Q tag is stripped and the traffic is removed from the tunnel.
QUESTION NO: 10
Given the above partial configuration, which two statements are true about VLAN traffic? (Choose two.)
A. VLANs 1-5 will use fa0/10 as a backup only.
B. VLANs 6-10 will use fa0/10 as a backup only.
C. VLANs 1-5 will be blocked if fa0/10 goes down.
D. VLANs 1-10 are configured to load share between fa0/10 and fa0/12.
E. VLANs 6-10 have a port priority of 128 on fa0/10.
Answer: B,D
Explanation:
Spanning-Tree Protocol (STP) is a Layer 2 protocol that utilizes a special-purpose algorithm to discover physical loops in a network and affect a logical loop-free topology. STP creates a loopfree tree structure consisting of leaves and branches that span the entire Layer 2 network. The actual mechanics of how bridges communicate and how the STP algorithm works will be discussed at length in the following topics. Note that the terms bridge and switch are used interchangeably when discussing STP. In addition, unless otherwise indicated, connections between switches are assumed to be trunks.
Load sharing can be accomplished using a couple of methods. The most common method of load sharing is through root bridge placement on a per-VLAN basis. This will distribute traffic for separate VLANs across separate paths to different root bridges. A separate method divides the bandwidth supplied by parallel trunks connecting switches. To avoid loops, STP normally blocks all but one parallel link between switches. Using load sharing, traffic can be divided between the links according to which VLAN the traffic belongs.
Load sharing can be configured on trunk ports by using STP port priorities or STP path costs. For load sharing using STP port priorities, both load-sharing links must be connected to the same switch. For load sharing using STP path costs, each load-sharing link can be connected to the same switch or to two different switches.
Load Sharing Using STP Port Priorities
When two ports on the same switch form a loop, the STP port priority setting determines which port is enabled and which port is in a blocking state. The priorities on a parallel trunk port can be set so that the port carries all the traffic for a given VLAN. The trunk port with the higher priority (lower values) for a VLAN is forwarding traffic for that VLAN. The trunk port with the lower priority (higher values) for the same VLAN remains in a Blocking state for that VLAN. One trunk port sends or receives all traffic for the VLAN.
Why answer “E” is not correctly?