Scaling Networks Version 6 – ScaN Chapter 6 Exam

Scaling Networks (Version 6.00) – ScaN Chapter 6 Exam


Which statement about slow inter VLAN forwarding is true?

A.The VLAN is experiencing slowness in the point-to-point collisionless connection.
B.The VLANs are experiencing slowness because multiple devices are connected to the same hub.
C.The local VLAN is working normally, but traffic to the alternate VLAN is forwarded slower than expected.
D.The entire VLAN is experiencing slowness.
E.The VLANs are experiencing slowness due to a duplex mismatch.

Correct Answer: E
Section: (none)

Common Causes of Slow IntraVLAN and InterVLAN Connectivity The symptoms of slow connectivity on a
VLAN can be caused by multiple factors on different network layers. Commonly the network speed issue
may be occurring on a lower level, but symptoms can be observed on a higher level as the problem masks
itself under the term “slow VLAN”. To clarify, this document defines the following new terms: “slow collision
domain”, “slow broadcast domain” (in other words, slow VLAN), and “slow interVLAN forwarding”. These
are defined in the section Three Categories of Causes, below.
In the following scenario (illustrated in the network diagram below), there is a Layer 3 (L3) switch performing
interVLAN routing between the server and client VLANs. In this failure scenario, one server is connected to
a switch, and the port duplex mode is configured half- duplex on the server side and full-duplex on the
switch side. This misconfiguration results in a packet loss and slowness, with increased packet loss when
higher traffic rates occur on the link where the server is connected. For the clients who communicate with
this server, the problem looks like slow interVLAN forwarding because they do not have a problem
communicating to other devices or clients on the same VLAN. The problem occurs only when
communicating to the server on a different VLAN. Thus, the problem occurred on a single collision domain,
but is seen as slow interVLAN forwarding.

Three Categories of Causes
The causes of slowness can be divided into three categories, as follows:
Slow Collision Domain Connectivity
Collision domain is defined as connected devices configured in a half-duplex port configuration, connected
to each other or a hub. If a device is connected to a switch port and full-duplex mode
is configured, such a point-to-point connection is collisionless. Slowness on such a segment still can occur
for different reasons.
Slow Broadcast Domain Connectivity (Slow VLAN)
Slow broadcast domain connectivity occurs when the whole VLAN (that is, all devices on the same VLAN)
experiences slowness.
Slow InterVLAN Connectivity (Slow Forwarding Between VLANs) Slow interVLAN connectivity (slow
forwarding between VLANs) occurs when there is no slowness on the local VLAN, but traffic needs to be
forwarded to an alternate VLAN, and it is not forwarded at the expected rate.
Causes for Network Slowness
Packet Loss
In most cases, a network is considered slow when higher-layer protocols (applications) require extended
time to complete an operation that typically runs faster. That slowness is caused by the loss of some
packets on the network, which causes higher-level protocols like TCP or applications to time out and initiate
Hardware Forwarding Issues
With another type of slowness, caused by network equipment, forwarding (whether Layer 2 [L2] or L3) is
performed slowly. This is due to a deviation from normal (designed) operation and switching to slow path
forwarding. An example of this is when Multilayer Switching (MLS) on the switch forwards L3 packets
between VLANs in the hardware, but due to misconfiguration, MLS is not functioning properly and
forwarding is done by the router in the software (which drops the interVLAN forwarding rate significantly).


Which statement about the IP SLAs ICMP Echo operation is true?

A.The frequency of the operation .s specified in milliseconds.
B.It is used to identify the best source interface from which to send traffic.
C.It is configured in enable mode.
D.It is used to determine the frequency of ICMP packets.

Correct Answer: D
Section: (none)

This module describes how to configure an IP Service Level Agreements (SLAs) Internet Control Message
Protocol (ICMP) Echo operation to monitor end-to-end response time between a Cisco router and devices
using IPv4 or IPv6. ICMP Echo is useful for troubleshooting network connectivity issues. This module also
demonstrates how the results of the ICMP Echo operation can be displayed and analyzed to determine how
the network IP connections are performing.
ICMP Echo Operation
The ICMP Echo operation measures end-to-end response time between a Cisco router and any devices
using IP. Response time is computed by measuring the time taken between sending an ICMP Echo request
message to the destination and receiving an ICMP Echo reply. In the figure below ping is used by the ICMP
Echo operation to measure the response time between the source IP SLAs device and the destination IP
device. Many customers use IP SLAs ICMP-based operations, in-house ping testing, or ping-based
dedicated probes for response time measurements.

The IP SLAs ICMP Echo operation conforms to the same IETF specifications for ICMP ping testing and the
two methods result in the same response times. Configuring a Basic ICMP Echo Operation on the Source

1. enable
2. configure terminal
3. ip sla operation-number
4. icmp-echo {destination-ip-address | destination-hostname} [source-ip {ip-address | hostname} | sourceinterface interface-name]
5. frequency seconds 6. end


Which option describes how a switch in rapid PVST+ mode responds to a topology change?

A.It immediately deletes dynamic MAC addresses that were learned by all ports on the switch.
B.It sets a timer to delete all MAC addresses that were learned dynamically by ports in the same STP
C.It sets a timer to delete dynamic MAC addresses that were learned by all ports on the switch.
D.It immediately deletes all MAC addresses that were learned dynamically by ports in the same STP

Correct Answer: D
Section: (none)

Rapid PVST+This spanning-tree mode is the same as PVST+ except that is uses a rapid convergence
based on the IEEE 802.1w standard. To provide rapid convergence, the rapid PVST+ immediately deletes
dynamically learned MAC address entries on a per-port basis upon receiving a topology change. By
contrast, PVST+ uses a short aging time for dynamically learned MAC address entries.
The rapid PVST+ uses the same configuration as PVST+ (except where noted), and the switch needs only
minimal extra configuration. The benefit of rapid PVST+ is that you can migrate a large PVST+ install base
to rapid PVST+ without having to learn the complexities of the MSTP configuration and without having to
reprovision your network. In rapid-PVST+ mode, each VLAN runs its own spanning-tree instance up to the
maximum supported.


Which type of topology is required by DMVPN?

B.full mesh
D.partial mesh

Correct Answer: C
Section: (none)


Refer to the exhibit. Router edge-1 is unable to establish OSPF neighbor adjacency with router ISP-1.
Which two configuration changes can you make on edge-1 to allow the two routers to establish adjacency? (Choose two.)

A.Set the subnet mask on edge-1 to 255 255.255.252.
B.Reduce the MTU on edge-1 to 1514.
C.Set the OSPF cost on edge-1 to 1522.
D.Reduce the MTU on edge-1 to 1500.
E.Configure the ip ospf mtu-ignore command on the edge-1 Gi0/0 interface.

Correct Answer: DE
Section: (none)

A situation can occur where the interface MTU is at a high value, for example 9000, while the real value of
the size of packets that can be forwarded over this interface is 1500.
If there is a mismatch on MTU on both sides of the link where OSPF runs,
then the OSPF adjacency will not form because the MTU value is carried in the Database Description
(DBD) packets and checked on the other side.


Which statement about switch access ports is true?

A.They drop packets with 802.1Q tags.
B.A VLAN must be assigned to an access port before it is created.
C.They can receive traffic from more than one VLAN with no voice support
D.By default, they carry traffic for VLAN 10.

Correct Answer: A
Section: (none)

“If an access port receives a packet with an 802.1Q tag in the header other than the access VLAN value,
that port drops the packet without learning its MAC source address.”


Which option is a benefit of switch stacking?

A.It provides redundancy with no impact on resource usage.
B.It simplifies adding and removing hosts.
C.It supports better performance of high-needs applications.
D.It provides higher port density with better resource usage.

Correct Answer: D
Section: (none)

A stackable switch is a network switch that is fully functional operating standalone but which can also be set
up to operate together with one or more other network switches, with this group of switches showing the
characteristics of a single switch but having the port capacity of the sum of the combined switches.


What is the first step you perform to configure an SNMPv3 user?

A.Configure server traps.
B.Configure the server group.
C.Configure the server host.
D.Configure the remote engine ID.

Correct Answer: B
Section: (none)

The first task in configuring SNMPv3 is to define a view. To simplify things, we’ll create a view that allows
access to the entire internet subtree:
router(config)#snmp-server view readview internet included This command creates a view called readview.
If you want to limit the view to the system tree, for example, replace internet with system. The included
keyword states that the specified tree should be included in the view; use excluded if you wanted to exclude
a certain subtree.
Next, create a group that uses the new view. The following command creates a group called readonly ; v3
means that SNMPv3 should be used. The auth keyword specifies that the entity should authenticate
packets without encrypting them; read readview says that the view named readview should be used whenever members of the readonly group access
the router. router(config)#snmp-server group readonly v3 auth read readview


Which statement about named ACLs is true?

A.They support standard and extended ACLs.
B.They are used to filter usernames and passwords for Telnet and SSH.
C.They are used to filter Layer 7 traffic.
D.They support standard ACLs only.
E.They are used to rate limit traffic destined to targeted networks.

Correct Answer: A
Section: (none)

Named Access Control Lists (ACLs) allows standard and extended ACLs to be given names instead of
numbers. Unlike in numbered Access Control Lists (ACLs), we can edit Named Access Control Lists.
Another benefit of using named access configuration mode is that you can add new statements to the
access list, and insert them wherever you like. With the legacy syntax, you must delete the entire access list
before reapplying it using the updated rules.


Which two switch states are valid for 802.1w? (Choose two.)


Correct Answer: DE
Section: (none)

Port States
There are only three port states left in RSTP that correspond to the three possible operational states. The
802.1D disabled, blocking, and listening states are merged into a unique 802.1w discarding state.


Which statement about MPLS is true?

A.It operates in Layer 1.
B.It operates between Layer 2 and Layer 3.
C.It operates in Layer 3. operates in Layer 2.

Correct Answer: B
Section: (none)

MPLS belongs to the family of packet-switched networks. MPLS operates at a layer that is generally
considered to lie between traditional definitions of OSI Layer 2 (data link layer) and Layer 3 (network layer),
and thus is often referred to as a layer 2.5 protocol.


Which Cisco platform can verify ACLs?

A.Cisco Prime Infrastructure
B.Cisco Wireless LAN Controller
D.Cisco IOS-XE

Correct Answer: B
Section: (none)


Which three options are the HSRP states for a router? (Choose three.)

F. primary

Correct Answer: BDE
Section: (none)

HSRP States


You enter the show ipv6 route command on an OSPF device and the device displays a route.
Which conclusion can you draw about the environment?

A.OSPF is distributing IPv6 routes to BGP.
B.The router is designated as an ABR.
C.The router is designated as totally stubby.
D.OSPFv3 is in use.

Correct Answer: A
Section: (none)


Which NTP command configures the local device as an NTP reference clock source?

A.ntp peer
B.ntp broadcast
C.ntp master
D.ntp server

Correct Answer: D
Section: (none)

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