CertBus 2018 Hottest Cisco 400-101 CCIE Exam VCE and PDF Dumps for Free Download!
☆ 400-101 CCIE Exam PDF and VCE Dumps : 1436QAs Instant Download: https://www.certbus.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.certbus.com/online-pdf/400-101.pdf
☆ CertBus 2018 Hottest 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 1436QAs are all new published by Cisco Official Exam Center
No debt that the Cisco CCIE Newest 400-101 free download dumps are very popular and CertBus provides variety of Cisco CCIE Latest 400-101 vce exam dumps in PDF and VCE format. CertBus will continue to release latest CCIE Nov 09,2018 Hotest 400-101 pdf dumps CCIE Routing and Switching Written v5.0 study materials to meet the rapidly increasing demand of the IT industry.
CertBus – 100% real 400-101 certification exam questions and answers. easily pass with a high score. CertBus goal is to help you get passed in all CertBus certification exams first attempt. high pass rate and success rate. reliable 400-101 certification exams preparation – latest braindumps at CertBus. updated 2016 for all 400-101 top certifications | CertBus .
We CertBus has our own expert team. They selected and published the latest 400-101 preparation materials from Cisco Official Exam-Center: https://www.certbus.com/400-101.html
A new backup connection is being deployed on a remote site router. The stability of the connection
has been a concern. In order to provide more information to EIGRP regarding this interface, you
wish to incorporate the “reliability” cost metric in the EIGRP calculation with the command metric
weights 1 0 1 0 1.
What impact will this modification on the remote site router have for other existing EIGRP
neighborships from the same EIGRP domain?
A. Existing neighbors will immediately begin using the new metric.
B. Existing neighbors will use the new metric after clearing the EIGRP neighbors.
C. Existing neighbors will resync, maintaining the neighbor relationship.
D. All existing neighbor relationships will go down.
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.
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
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
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
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:
Which two options are contained in a VTP subset advertisement? (Choose two.)
A. followers field
B. MD5 digest
C. VLAN information
D. sequence number
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:
Which two statements are true about traffic shaping? (Choose two.)
A. Out-of-profile packets are queued.
B. It causes TCP retransmits.
C. Marking/remarking is not supported.
D. It does not respond to BECN and ForeSight Messages.
E. It uses a single/two-bucket mechanism for metering.
In 802.1s, how is the VLAN to instance mapping represented in the BPDU?
A. The VLAN to instance mapping is a normal 16-byte field in the MST BPDU.
B. The VLAN to instance mapping is a normal 12-byte field in the MST BPDU.
C. The VLAN to instance mapping is a 16-byte MD5 signature field in the MST BPDU.
D. The VLAN to instance mapping is a 12-byte MD5 signature field in the MST BPDU.
MST Configuration and MST Region
Each switch running MST in the network has a single MST configuration that consists of these
1. An alphanumeric configuration name (32 bytes)
2. A configuration revision number (two bytes)
3. A 4096-element table that associates each of the potential 4096 VLANs supported on the
chassis to a given instance.
In order to be part of a common MST region, a group of switches must share the same
It is up to the network administrator to properly propagate the configuration throughout the region.
Currently, this step is only possible by the means of the command line interface (CLI) or through
Management Protocol (SNMP). Other methods can be envisioned, as the IEEE specification does
not explicitly mention how to accomplish that step.
Note: If for any reason two switches differ on one or more configuration attribute, the switches are
part of different regions. For more information refer to the Region Boundary section of this
In order to ensure consistent VLAN-to-instance mapping, it is necessary for the protocol to be able
to exactly identify the boundaries of the regions. For that purpose, the characteristics of the region
are included in the BPDUs. The exact VLANs-to-instance mapping is not propagated in the BPDU,
because the switches only need to know whether they are in the same region as a neighbor.
Therefore, only a digest of the VLANs-toinstance mapping table is sent, along with the revision
number and the name. Once a switch receives a BPDU, the switch extracts the digest (a
numerical value derived from the VLAN-to-instance mapping table through a mathematical
function) and compares this digest with its own computed digest. If the digests differ, the port on
which the BPDU was received is at the boundary of a region.
In generic terms, a port is at the boundary of a region if the designated bridge on its segment is in
a different region or if it receives legacy 802.1d BPDUs. In this diagram, the port on B1 is at the
boundary of region A, whereas the ports on B2 and B3 are internal to region B:
According to the IEEE 802.1s specification, an MST bridge must be able to handle at least these
One Internal Spanning Tree (IST)
One or more Multiple Spanning Tree Instance(s) (MSTIs)
The terminology continues to evolve, as 802.1s is actually in a pre-standard phase. It is likely
these names will change in the final release of 802.1s. The Cisco implementation supports 16
instances: one IST (instance 0) and 15 MSTIs.
show vtp status
Cisco switches “show vtp status” Field Descriptions has a MD5 digest field that is a 16-byte
checksum of the
VTP configuration as shown below
Router# show vtp status
VTP Version: 3 (capable)
Configuration Revision: 1
Maximum VLANs supported locally: 1005
Number of existing VLANs: 37
VTP Operating Mode: Server
VTP Domain Name: [smartports]
VTP Pruning Mode: Disabled
VTP V2 Mode: Enabled
VTP Traps Generation: Disabled
MD5 digest : 0x26 0xEE 0x0D 0x84 0x73 0x0E 0x1B 0x69
Configuration last modified by 172.20.52.19 at 7-25-08 14:33:43
Local updater ID is 172.20.52.19 on interface Gi5/2 (first layer3 interface fou)
VTP version running: 2
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.
Which two tunneling techniques support IPv6 multicasting? (Choose two.)
When IPv6 multicast is supported (over a 6to4 tunnel), an IPv6 multicast routing protocol must be
Restrictions for Implementing IPv6 Multicast
IPv6 multicast for Cisco IOS software uses MLD version 2. This version of MLD is fully backward-
compatible with MLD version 1 (described in RFC 2710). Hosts that support only MLD version 1
will interoperate with a router running MLD version 2. Mixed LANs with both MLD version 1 and
MLD version 2 hosts are likewise supported.
IPv6 multicast is supported only over IPv4 tunnels in Cisco IOS Release 12.3(2)T, Cisco IOS
(18)S, and Cisco IOS Release 12.0(26)S.
When the bidirectional (bidir) range is used in a network, all routers in that network must be able to
understand the bidirectional range in the bootstrap message (BSM).
IPv6 multicast routing is disabled by default when the ipv6 unicast-routing command is configured.
On Cisco Catalyst 6500 and Cisco 7600 series routers, the ipv6 multicast-routing also must be
enabled in order to use IPv6 unicast routing
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
Which command can be used on a PE router to connect to a CE router (220.127.116.11) in VRF red?
A. telnet 18.104.22.168 /vrf-source red
B. telnet 22.214.171.124 source /vrf red
C. telnet 126.96.36.199 /source vrf red
D. telnet 188.8.131.52 /vrf red
E. telnet 184.108.40.206 vrf red
Telnetting can be done through the VRF using the Management Ethernet interface. In the
following example, the router telnets to 172.17.1.1 through the Management Ethernet interface
Router# telnet 172.17.1.1 /vrf Mgmt-intf
Refer to the exhibit.
Which interface(s) will show ip rpf 220.127.116.11 indicate as RPF interface(s)?
A. Ethernet 1/0
B. Ethernet 0/0
C. Both Ethernet 0/0 and Ethernet 1/0
D. RPF will fail
When troubleshooting multicast routing, the primary concern is the source address. Multicast has
a concept of Reverse Path Forwarding check (RPF check). When a multicast packet arrives on an
interface, the RPF process checks to ensure that this incoming interface is the outgoing interface
used by unicast routing to reach the source of the multicast packet. This RPF check process
prevents loops. Multicast routing does not forward a packet unless the source of the packet
passes a reverse path forwarding (RPF) check. Once a packet passes this RPF check, multicast
routing forwards the packet based only upon the destination address.
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.certbus.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 certbus.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.