Posted in Cisco Archives, ITExam Archives

Free Sharing CertBus Updated Cisco 400-101 VCE and PDF Exam Practice Materials

 Published Date: 08/21/2018

CertBus 2018 Latest Cisco 400-101 CCIE Exam VCE and PDF Dumps for Free Download!

☆ 400-101 CCIE Exam PDF and VCE Dumps : 1379QAs Instant Download: https://www.certgod.com/400-101.html [100% 400-101 Exam Pass Guaranteed or Money Refund!!]
☆ Free view online pdf on CertBus free test 400-101 PDF: https://www.certgod.com/online-pdf/400-101.pdf
☆ CertBus 2018 Latest 400-101 CCIE exam Question PDF Free Download from Google Drive Share: https://drive.google.com/file/d/0B_3QX8HGRR1mdEpkTFZvSDJDc2c/view?usp=sharing

Following 400-101 1379QAs are all new published by Cisco Official Exam Center

You can prepare for your Cisco CCIE Hotest 400-101 pdf exam with less time and effort because we,CertBus, will act as your reliable guide to pass your Cisco CCIE Aug 21,2018 Latest 400-101 free download exam. Our Cisco CCIE Latest 400-101 free download exam dumps are the latest and with the most accurate answers. We offer Cisco CCIE Latest 400-101 study guide PDF dumps and Cisco CCIE Newest 400-101 vce dumps VCE. Both are the most effective version.

latest CertBus 400-101 exam dumps pdf and vce free download. CertBus – the most professional 400-101 certification exam practice questions and answers provider. easily pass your 400-101 exams. just have a try! 4,500 exam dumps: pass your 400-101 certification exam with CertBus. 400-101 certification training tips | resources for 400-101 exam study 400-101 certification application guide and 400-101 training.

We CertBus has our own expert team. They selected and published the latest 400-101 preparation materials from Cisco Official Exam-Center: https://www.certgod.com/400-101.html

QUESTION NO:7

Which statement is true about TCN propagation?

A. The originator of the TCN immediately floods this information through the network.

B. The TCN propagation is a two step process.

C. A TCN is generated and sent to the root bridge.

D. The root bridge must flood this information throughout the network.

Answer: C

Explanation:

Explanation

New Topology Change Mechanisms

When an 802.1D bridge detects a topology change, it uses a reliable mechanism to first notify the

root bridge.

This is shown in this diagram:

Once the root bridge is aware of a change in the topology of the network, it sets the TC flag on the

BPDUs it sends out, which are then relayed to all the bridges in the network. When a bridge

receives a BPDU with the TC flag bit set, it reduces its bridging-table aging time to forward delay

seconds. This ensures a relatively quick flush of stale information. Refer to Understanding

Spanning-Tree Protocol Topology Changes for more information on this process. This topology

change mechanism is deeply remodeled in RSTP. Both the detection of a topology change and its

propagation through the network evolve.

Topology Change Detection

In RSTP, only non-edge ports that move to the forwarding state cause a topology change. This

means that a loss of connectivity is not considered as a topology change any more, contrary to

802.1D (that is, a port that moves to blocking no longer generates a TC). When a RSTP bridge

detects a topology change, these occur:

It starts the TC While timer with a value equal to twice the hello-time for all its non-edge

designated ports and its root port, if necessary.

It flushes the MAC addresses associated with all these ports.

Note: As long as the TC While timer runs on a port, the BPDUs sent out of that port have the TC

bit set.

BPDUs are also sent on the root port while the timer is active.

Topology Change Propagation

When a bridge receives a BPDU with the TC bit set from a neighbor, these occur:

It clears the MAC addresses learned on all its ports, except the one that receives the topology

change.

It starts the TC While timer and sends BPDUs with TC set on all its designated ports and root port

(RSTP no longer uses the specific TCN BPDU, unless a legacy bridge needs to be notified).

This way, the TCN floods very quickly across the whole network. The TC propagation is now a one

step process. In fact, the initiator of the topology change floods this information throughout the

network, as opposed to 802.1D where only the root did. This mechanism is much faster than the

802.1D equivalent. There is no need to wait for the root bridge to be notified and then maintain the

topology change state for the whole network for seconds.

In just a few seconds, or a small multiple of hello-times, most of the entries in the CAM tables of

the entire network (VLAN) flush. This approach results in potentially more temporary flooding, but

on the other hand it clears potential stale information that prevents rapid connectivity restitution.

Reference

http://www.cisco.com/en/US/tech/tk389/tk621/technologies_white_paper09186a0080094cfa.shtml

QUESTION NO:8

Which statement is true about loop guard?

A. Loop guard only operates on interfaces that are considered point-to-point by the spanning tree.

B. Loop guard only operates on root ports.

C. Loop guard only operates on designated ports.

D. Loop guard only operates on edge ports.

Answer: A

Explanation:

Explanation

Understanding How Loop Guard Works

Unidirectional link failures may cause a root port or alternate port to become designated as root if

BPDUs are absent. Some software failures may introduce temporary loops in the network. Loop

guard checks if a root port or an alternate root port receives BPDUs. If the port is receiving

BPDUs, loop guard puts the port into an inconsistent state until it starts receiving BPDUs again.

Loop guard isolates the failure and lets spanning tree converge to a stable topology without the

failed link or bridge.

You can enable loop guard per port with the set spantree guard loop command.

Note When you are in MST mode, you can set all the ports on a switch with the set spantree

global-defaults loop-guard command.

When you enable loop guard, it is automatically applied to all of the active instances or VLANs to

which that port belongs. When you disable loop guard, it is disabled for the specified ports.

Disabling loop guard moves all loop-inconsistent ports to the listening state.

If you enable loop guard on a channel and the first link becomes unidirectional, loop guard blocks

the entire channel until the affected port is removed from the channel. Figure 8-6 shows loop

guard in a triangle switch configuration.

Figure 8-6 Triangle Switch Configuration with Loop Guard

Figure 8-6 illustrates the following configuration:

Switches A and B are distribution switches.

Switch C is an access switch.

Loop guard is enabled on ports 3/1 and 3/2 on Switches A, B, and C.

Use loop guard only in topologies where there are blocked ports. Topologies that have no blocked

ports, which are loop free, do not need to enable this feature. Enabling loop guard on a root switch

has no effect but provides protection when a root switch becomes a nonroot switch.

Follow these guidelines when using loop guard:

Do not enable loop guard on PortFast-enabled or dynamic VLAN ports.

Do not enable PortFast on loop guard-enabled ports.

Do not enable loop guard if root guard is enabled.

Do not enable loop guard on ports that are connected to a shared link.

Note: We recommend that you enable loop guard on root ports and alternate root ports on access

switches.

Loop guard interacts with other features as follows:

Loop guard does not affect the functionality of UplinkFast or BackboneFast.

Root guard forces a port to always be designated as the root port. Loop guard is effective only if

the port is a root port or an alternate port. Do not enable loop guard and root guard on a port at the

same time.

PortFast transitions a port into a forwarding state immediately when a link is established. Because

a PortFast-enabled port will not be a root port or alternate port, loop guard and PortFast cannot be

configured on the same port. Assigning dynamic VLAN membership for the port requires that the

port is PortFast enabled. Do not configure a loop guard-enabled port with dynamic VLAN

membership.

If your network has a type-inconsistent port or a PVID-inconsistent port, all BPDUs are dropped

until the misconfiguration is corrected. The port transitions out of the inconsistent state after the

message age expires. Loop guard ignores the message age expiration on type-inconsistent ports

and PVID-inconsistent ports. If the port is already blocked by loop guard, misconfigured BPDUs

that are received on the port make loop guard recover, but the port is moved into the type-

inconsistent state or PVID-inconsistent state.

In high-availability switch configurations, if a port is put into the blocked state by loop guard, it

remains blocked even after a switchover to the redundant supervisor engine. The newly activated

supervisor engine recovers the port only after receiving a BPDU on that port.

Loop guard uses the ports known to spanning tree. Loop guard can take advantage of logical ports

provided by the Port Aggregation Protocol (PAgP). However, to form a channel, all the physical

ports grouped in the channel must have compatible configurations. PAgP enforces uniform

configurations of root guard or loop guard on all the physical ports to form a channel.

These caveats apply to loop guard:

QUESTION NO:11

When you are troubleshooting duplex mismatches, which two errors are typically seen on the full-

duplex end? (Choose two.)

A. runts

B. FCS errors

C. interface resets

D. late collisions

Answer: A,B

Explanation:

QUESTION NO:12

Which two options are contained in a VTP subset advertisement? (Choose two.)

A. followers field

B. MD5 digest

C. VLAN information

D. sequence number

Answer: C,D

Explanation:

Subset Advertisements

When you add, delete, or change a VLAN in a Catalyst, the server Catalyst where the changes are

made increments the configuration revision and issues a summary advertisement. One or several

subset advertisements follow the summary advertisement. A subset advertisement contains a list

of VLAN information.

If there are several VLANs, more than one subset advertisement can be required in order to

advertise all the VLANs.

Subset Advertisement Packet Format

This formatted example shows that each VLAN information field contains information for a different

VLAN. It is ordered so that lowered-valued ISL VLAN IDs occur first:

Most of the fields in this packet are easy to understand. These are two clarifications:

Code

QUESTION NO:14

Which three options are features of VTP version 3? (Choose three.)

A. VTPv3 supports 8K VLANs.

B. VTPv3 supports private VLAN mapping.

C. VTPv3 allows for domain discovery.

D. VTPv3 uses a primary server concept to avoid configuration revision issues.

E. VTPv3 is not compatible with VTPv1 or VTPv2.

F. VTPv3 has a hidden password option.

Answer: B,D,F

Explanation:

Key Benefits of VTP Version 3

Much work has gone into improving the usability of VTP version 3 in three major areas:

The new version of VTP offers better administrative control over which device is allowed to update

other devices\’ view of the VLAN topology. The chance of unintended and disruptive changes is

significantly reduced, and availability is increased. The reduced risk of unintended changes will

ease the change process and help speed deployment.

Functionality for the VLAN environment has been significantly expanded. Two enhancements are

most beneficial for today\’s networks:

400-101 VCE Dumps400-101 Practice Test400-101 Exam Questions

QUESTION NO:19

Which two options does Cisco PfR use to control the entrance link selection with inbound

optimization? (Choose two.)

A. Prepend extra AS hops to the BGP prefix.

B. Advertise more specific BGP prefixes (longer mask).

C. Add (prepend) one or more communities to the prefix that is advertised by BGP.

D. Have BGP dampen the prefix.

Answer: A,C

Explanation: PfR Entrance Link Selection Control Techniques

The PfR BGP inbound optimization feature introduced the ability to influence inbound traffic. A

network advertises reachability of its inside prefixes to the Internet using eBGP advertisements to

its ISPs. If the same prefix is advertised to more than one ISP, then the network is multihoming.

PfR BGP inbound optimization works best with multihomed networks, but it can also be used with

a network that has multiple connections to the same ISP. To implement BGP inbound

optimization, PfR manipulates eBGP advertisements to influence the best entrance selection for

traffic bound for inside prefixes. The benefit of implementing the best entrance selection is limited

to a network that has more than one ISP connection.

To enforce an entrance link selection, PfR offers the following methods:

BGP Autonomous System Number Prepend When an entrance link goes out-of-policy (OOP) due

to delay, or in images prior to Cisco IOS Releases 15.2(1) T1 and 15.1(2)S, and PfR selects a

best entrance for an inside prefix, extra autonomous system hops are prepended one at a time (up

to a maximum of six) to the inside prefix BGP advertisement over the other entrances. In Cisco

IOS Releases 15.2(1)T1, 15.1(2)S, and later releases, when an entrance link goes out-of policy

(OOP) due to unreachable or loss reasons, and PfR selects a best entrance for an inside prefix,

six extra autonomous system hops are prepended immediately to the inside prefix BGP

advertisement over the other entrances. The extra autonomous system hops on the other

entrances increase the probability that the best entrance will be used for the inside prefix. When

the entrance link is OOP due to unreachable or loss reasons, six extra autonomous system hops

are added immediately to allow the software to quickly move the traffic away from the old entrance

link. This is the default method PfR uses to control an inside prefix, and no user configuration is

required.

BGP Autonomous System Number Community Prepend

When an entrance link goes out-of-policy (OOP) due to delay, or in images prior to Cisco IOS

Releases 15.2

(1)T1 and 15.1(2)S, and PfR selects a best entrance for an inside prefix, a BGP prepend

community is attached one at a time (up to a maximum of six) to the inside prefix BGP

advertisement from the network to another autonomous system such as an ISP. In Cisco IOS

Releases 15.2(1)T1, 15.1(2)S, and later releases, when an entrance link goes out-of-policy (OOP)

due to unreachable or loss reasons, and PfR selects a best entrance for an inside prefix, six BGP

prepend communities are attached to the inside prefix BGP advertisement. The BGP prepend

community will increase the number of autonomous system hops in the advertisement of the

inside prefix from the ISP to its peers. Autonomous system prepend BGP community is the

preferred method to be used for PfR BGP inbound optimization because there is no risk of the

local ISP filtering the extra autonomous system hops. There are some issues, for example, not all

ISPs support the BGP prepend community, ISP policies may ignore or modify the autonomous

system hops, and a transit ISP may filter the autonomous system path. If you use this method of

inbound optimization and a change is made to an autonomous system, you must issue an

outbound reconfiguration using the “clear ip bgp” command.

Reference

http://www.cisco.com/en/US/docs/ios-xml/ios/pfr/configuration/15-2s/pfr-bgp-inbound.html#GUID-

F8A59E241D59-

4924-827D-B23B43D9A8E0

http://www.cisco.com/en/US/products/ps8787/products_ios_protocol_option_home.html

QUESTION NO:20

Refer to the exhibit.

What is the potential issue with this configuration?

A. There is no potential issue; OSPF will work fine in any condition.

B. Sub-optimal routing may occur since there is no area 1 adjacency between the ABRs.

C. This is a wrong OSPF configuration because all routers must be in area 0 only.

D. This is a wrong OSPF configuration because /30 requires 0.0.0.3 wild card.

Answer: B

Explanation:

QUESTION NO:27

Refer to the exhibit.

What triggered the first SPF recalculation?

A. changes in a router LSA, subnet LSA, and external LSA

B. changes in a router LSA, summary network LSA, and external LSA

C. changes in a router LSA, summary network LSA, and summary ASBR LSA

D. changes in a router LSA, summary ASBR LSA, and external LSA

Answer: B

Explanation:

OSPFv2

Is built around links, and any IP prefix change in an area will trigger a full SPF. It advertises IP

information in Router and Network LSAs. The routers thus, advertise both the IP prefix information

(or the connected subnet information) and topology information in the same LSAs. This implies

that if an IP address attached to an interface changes, OSPF routers would have to originate a

Router LSA or a Network LSA, which btw also carries the topology information. This would trigger

a full SPF on all routers in that area, since the same LSAs are flooded to convey topological

change information. This can be an issue with an access router or the one sitting at the edge,

since many stub links can change regularly.

Only changes in interarea, external and NSSA routes result in partial SPF calculation (since type

3, 4, 5 and 7 LSAs only advertise IP prefix information) and thus IS-IS

QUESTION NO:29

What is the first thing that happens when IPv6 is enabled on an interface on a host?

A. A router solicitation is sent on that interface.

B. There is a duplicate address detection on the host interface.

C. The link local address is assigned on the host interface.

D. A neighbor redirect message is sent on the host interface.

Answer: B

Explanation:

Duplicate address detection (DAD) is used to verify that an IPv6 home address is unique on the

LAN before assigning the address to a physical interface (for example, QDIO). z/OS

Communications Server responds to other nodes doing DAD for IP addresses assigned to the

interface.

Reference

http://publib.boulder.ibm.com/infocenter/zos/v1r12/index.jsp?topic=/com.ibm.zos.r12.hale001

/ipv6d0021002145.htm

QUESTION NO:36

For which routes does LDP advertise a label binding?

A. all routes in the routing table

B. only the IGP and BGP routes in the routing table

C. only the BGP routes in the routing table

D. only the IGP routes in the routing table

Answer: D

Explanation:

CertBus exam braindumps are pass guaranteed. We guarantee your pass for the 400-101 exam successfully with our Cisco materials. CertBus CCIE Routing and Switching Written v5.0 exam PDF and VCE are the latest and most accurate. We have the best Cisco in our team to make sure CertBus CCIE Routing and Switching Written v5.0 exam questions and answers are the most valid. CertBus exam CCIE Routing and Switching Written v5.0 exam dumps will help you to be the Cisco specialist, clear your 400-101 exam and get the final success.

400-101 Latest questions and answers on Google Drive(100% Free Download): https://drive.google.com/file/d/0B_3QX8HGRR1mdEpkTFZvSDJDc2c/view?usp=sharing

400-101 Cisco exam dumps (100% Pass Guaranteed) from CertBus: https://www.certgod.com/400-101.html [100% Exam Pass Guaranteed]

Why select/choose CertBus?

Millions of interested professionals can touch the destination of success in exams by certgod.com. products which would be available, affordable, updated and of really best quality to overcome the difficulties of any course outlines. Questions and Answers material is updated in highly outclass manner on regular basis and material is released periodically and is available in testing centers with whom we are maintaining our relationship to get latest material.

BrandCertbusTestkingPass4sureActualtestsOthers
Price$45.99$124.99$125.99$189$69.99-99.99
Up-to-Date Dumps
Free 365 Days Update
Real Questions
Printable PDF
Test Engine
One Time Purchase
Instant Download
Unlimited Install
100% Pass Guarantee
100% Money Back
Secure Payment
Privacy Protection