[Free] 2019(Nov) EnsurePass Cisco 300-115 Dumps with VCE and PDF 1-10

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Question No.1

What is the size of the VLAN field inside an 802.1q frame?

  1. 8-bit

  2. 12-bit

  3. 16-bit

  4. 32-bit

Correct Answer: B


The VLAN field is a 12-bit field specifying the VLAN to which the frame belongs. The hexadecimal values of 0x000 and 0xFFF are reserved. All other values may be used as VLAN identifiers, allowing up to 4,094 VLANs

Reference: http://en.wikipedia.org/wiki/IEEE_802.1Q

Question No.2

A manager tells the network engineer to permit only certain VLANs across a specific trunk interface. Which option can be configured to accomplish this?

  1. allowed VLAN list

  2. VTP pruning

  3. VACL

  4. L2P tunneling

Correct Answer: A


When a trunk link is established, all of the configured VLANs are allowed to send and receive traffic across the link. VLANs 1 through 1005 are allowed on each trunk by default. However, VLAN traffic can be removed from the allowed list. This keeps traffic from the VLANs from passing over the trunk link.

Note: The allowed VLAN list on both the ends of the trunk link should be the same. For Integrated Cisco IOS Software based switches, perform these steps:

1. To restrict the traffic that a trunk carries, issue the switchport trunk vlan-list interface configuration command.

This removes specific VLANs from the allowed list.

Reference: https://supportforums.cisco.com/document/11836/how-define-vlans-allowed-trunk-link

Question No.3

For security reasons, the IT manager has prohibited users from dynamically establishing trunks with their associated upstream switch. Which two actions can prevent interface trunking? (Choose two.)

  1. Configure trunk and access interfaces manually.

  2. Disable DTP on a per interface basis.

  3. Apply BPDU guard and BPDU filter.

  4. Enable switchport block on access ports.

Correct Answer: AB


The Dynamic Trunking Protocol (DTP) is used to negotiate forming a trunk between two Cisco devices. DTP causes increased traffic, and is enabled by default, but may be disabled. To disable DTP, configure quot;switchport nonegotiate.quot; This prevents the interface from generating DTP frames. You can use this command only when the interface switchport mode is access or trunk. You must manually configure the neighboring interface as a trunk interface to establish a trunk link,

otherwise the link will be a non-trunking link. Reference:http://www.ciscopress.com/articles/article.asp?p=2181837amp;seqNum=8

Question No.4

Refer to the exhibit. Which option shows the expected result if a show vlan command is issued?








Correct Answer: A


In this case, the port has been configured both as a trunk and as a switchport in data vlan 10. Obviously, a port can not be both, soeven thoughCisco IOSwill accept both, the port will actually be used as a trunk, ignoring the switchport access VLAN 10 command.

Question No.5

In a Cisco switch, what is the default period of time after which a MAC address ages out and is discarded?

  1. 100 seconds

  2. 180 seconds

  3. 300 seconds

  4. 600 seconds

Correct Answer: C


To configure the aging time for all MAC addresses, perform this task:

Command Purpose Step 1

switch#configure terminal Enters configuration mode.

Step 2

switch(config)#mac-address-table aging-timeseconds[vlanvlan_id] Specifies the time before an entry ages out and is discarded from the MAC address table. The range is from 0 to 1000000;the default is 300 seconds. Entering the value 0 disables the MAC aging. If a VLAN is not specified, the aging specification applies to all VLANs.

Reference: http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/configuration/guide/cli/MAC Address.html

Question No.6

Which statement about Cisco devices learning about each other through Cisco Discovery Protocol is true?

  1. Each device sends periodic advertisements to multicast address 01:00:0C:CC:CC:CC.

  2. Each device broadcasts periodic advertisements to all of its neighbors.

  3. Each device sends periodic advertisements to a central device that builds the network topology.

  4. Each device sends periodic advertisements to all IP addresses in its ARP table.

Correct Answer: A


Cisco devices send periodic CDP announcements to the multicast destination address 01-00-0c- cc-cc-cc, out each connected network interface. These multicast packets may be received by Cisco switches and other networking devices that support CDP into their connected network interface.


Question No.7

Refer to the exhibit. Which EtherChannel negotiation protocol is configured on the interface f0/13

– f0/15?


  1. Link Combination Control Protocol

  2. Port Aggregation Protocol

  3. Port Combination Protocol

  4. Link Aggregation Control Protocol

Correct Answer: B


PAgP modes are off, auto, desirable, and on. Only the combinations auto-desirable, desirable- desirable, and on-on will allow a channel to be formed. .

The Link Aggregate Control Protocol (LACP) trunking supports four modes of operation:

In this example, we see that fa 0/13, fa0/14, and fa0/15 are all in Port Channel 12, which is operating in desirable mode, which is only a PAgP mode. all in Port Channel 12, which is operating in desirable mode, which is only a PAgP mode.

Question No.8

Which two protocols can be automatically negotiated between switches for trunking? (Choose two.)

  1. PPP

  2. DTP

  3. ISL

  4. HDLC

  5. DLCI

  6. DOT1Q

Correct Answer: CF


Switches such as the Catalyst 3550 that are capable of either 802.1Q or ISL trunking encapsulation, the switchport trunk encapsulation [dot1q | isl | negotiate] interface command must be used prior to the switchport mode trunk command.

Reference:https://learningnetwork.cisco.com/servlet/JiveServlet/previewBody/14792-102-1- 57313/Dynamic Trunking Protocol.PDF

Question No.9

Which option is a possible cause for an errdisabled interface?

  1. routing loop

  2. cable unplugged

  3. STP loop guard

  4. security violation

Correct Answer: D


There are various reasons for the interface to go into errdisable. The reason can be: Duplex mismatch

Port channel misconfiguration BPDU guard violation

UniDirectional Link Detection (UDLD) condition Late-collision detection

Link-flap detection Security violation

Port Aggregation Protocol (PAgP) flap Layer 2 Tunneling Protocol (L2TP) guard DHCP snooping rate-limit

Incorrect GBIC / Small Form-Factor Pluggable (SFP) module or cable Address Resolution Protocol (ARP) inspection

Inline power Reference:http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a00 806cd87b.shtml

Question No.10

A network engineer notices inconsistent Cisco Discovery Protocol neighbors according to the diagram that is provided. The engineer notices only a single neighbor that uses Cisco Discovery Protocol, but it has several routing neighbor relationships. What would cause the output to show only the single neighbor?

  1. The routers are connected via a Layer 2 switch.

  2. IP routing is disabled on neighboring devices.

  3. Cisco Express Forwarding is enabled locally.

  4. Cisco Discovery Protocol advertisements are inconsistent between the local and remote devices.

Correct Answer: A


If all of the routers are connected to each other using a layer 2 switch, then each router will only have the single switch port that it connects to as its neighbor. Even though multiple routing neighbors can be formed over a layer 2 network, only the physical port that it connects to will be seen as a CDP neighbor. CDP can be used to determine the physical topology, but not necessarily the logical topology.

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