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642-813 Q&A – Implement VLAN based solution (26-30)

Section 1 – Implement VLAN based solution, given a network design and a set of requirements

Which of the following specifications is a companion to the IEEE 802.1w Rapid Spanning Tree Protocol (RSTP) algorithm, and warrants the use multiple spanning-trees?
A. IEEE 802.1s (MST)
B. IEEE 802.1Q (CST)
C. Cisco PVST+
D. IEEE 802.1d (STP)
E. None of the other alternatives apply

Answer: A
MST uses the modified RSTP version called the Multiple Spanning Tree Protocol (MSTP). MST extends the IEEE 802.1w rapid spanning tree (RST) algorithm to multiple spanning trees. This extension provides both rapid convergence and load balancing in a VLAN environment. MST converges faster than PVST+. MST is backward compatible with 802.1D STP, 802.1w (rapid spanning tree protocol [RSTP]), and the Cisco PVST+ architecture.
MST allows you to build multiple spanning trees over trunks. You can group and associate VLANs to spanning tree instances. Each instance can have a topology independent of other spanning tree instances. This new architecture provides multiple forwarding paths for data traffic and enables load balancing. Network fault tolerance is improved because a failure in one instance (forwarding path) does not affect other instances (forwarding paths).
In large networks, you can more easily administer the network and use redundant paths by locating different VLAN and spanning tree instance assignments in different parts of the network.
A spanningtree instance can exist only on bridges that have compatible VLAN instance assignments. You must configure a set of bridges with the same MST configuration information, which allows them to participate in a specific set of spanning tree instances. Interconnected bridges that have the same MST configuration are referred to as an MST region.

You are assigning VLANs to the ports of switch R1. What VLAN number value is an assigned to the default VLAN?
A. VLAN 1003
Answer: B
The default VLAN is VLAN 1. Although this VLAN can be modified, it can not be deleted from the switch. The following VLANs are on by default for all Cisco Catalyst switches:
VLAN 1 – Default VLAN
VLAN 1002 – Default FDDI VLAN
VLAN 1003 – Default Token Ring VLAN
VLAN 1004 – Default FDDI Net VLAN
VLAN 1005 – Default Token Ring Net VLAN
Incorrect Answers:
A: This is the default Token Ring VLAN that is installed in the switch IOS. It is seldom used.
C: ON is a VTP configuration mode, but is not a normal VLAN name.
D: Although any VLAN can be named VLAN A, it is not created by default.
E: Although in Cisco IOS the number 0 has significance (i.e. ethernet 0, console port 0, serial 0) in VLANs 1 is the default. VLAN 0 is an invalid VLAN and can not be used.

The Company administrator has issue the "show vlan id 5" command. What will this command display? (Select two)
A. Ports in VLAN 5
B. Utilization
C. VLAN information on port 0/5
D. Filters
E. MTU and type
Answer: A,E
#show vlan id 5 : Shows all ports belonging to VLAN 5 and MTU of ports and type.

Which MST configuration statement is correct?
A. MST configurations can be propagated to other switches using VTP.
B. After MST is configured on a Switch, PVST+ operations will also be enabled by default.
C. MST configurations must be manually configured on each switch within the MST region.
D. MST configurations only need to be manually configured on the Root Bridge.
E. MST configurations are entered using the VLAN Database mode on Cisco Catalyst switches.
Answer: C
MST configuration must be manually be configured on each switch within the MST region.

In the three-layer hierarchical network design model; what’s associated with the access layer? (Select two)
A. optimized transport structure
B. high port density
C. boundary definition
D. data encryption
E. local VLANs
F. route summaries
Answer: B,E
The access layer is the outermost layer, and it is composed of the least sophisticated network equipment. The most important function of the access layer is high port density, since these devices connect the individual end users. The access layers are also where VLANs are implemented, since VLANs are assigned on a per-port basis.