Home > VLAN Questions 4

VLAN Questions 4

November 24th, 2019 Go to comments

Question 1

Question 2

Question 3

Explanation

Normal range VLANs are from 1 to 1005 (in which VLANs 1002 to 1005 are Cisco defaults for FDDI and Token Ring. You cannot delete these VLANs). Extended range VLANs are from 1006 to 4094.

Question 4

Question 5

Explanation

If VLAN 20 has not been created in the switch then the command “switchport access vlan 20” will automatically create this VLAN.

Question 6

Question 7

Explanation

You can configure an access port with an attached Cisco IP Phone to use one VLAN for voice traffic and another VLAN for data traffic from a device attached to the phone -> Therefore we can configure two VLANs in total.

Reference: https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2960/software/release/12-2_40_se/configuration/guide/scg/swvoip.pdf

Question 8

Explanation

Normal range VLANs are from 1 to 1005 (in which VLANs 1002 to 1005 are Cisco defaults for FDDI and Token Ring. You cannot delete these VLANs). Extended range VLANs are from 1006 to 4094. When you configure VLANs in VLAN database mode, the VLAN configuration is saved in the vlan.dat file, not the running-config or startup-config files.

When the switch is in VTP server or transparent mode, you can configure VLANs in the VLAN database mode.

Question 9

Explanation

VTPv3 supports for extended VLAN range (VLANs 1006 to 4094). VTP versions 1 and 2 only supports VLANs 1 to 1005. If extended VLANs are configured, we cannot convert from VTP version 3 to version 1 or 2. VTP version 3 saves extended-range VLANs in the VLAN database.

Reference: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3560/software/release/12-2_52_se/configuration/guide/3560scg/swvtp.html

If you configure extended VLANs, you must also enable the spanning-tree extended system-ID feature (with the command “spanning-tree extend system-id”).

Reference: https://users.iit.uni-miskolc.hu/~szkovacs/HaloII/VLAN/ht_xvlan.pdf

Question 10

Question 11

Question 12

Explanation

CDP and VTP are always use VLAN 1 even if we change the native VLAN to another VLAN.

Comments
  1. HV
    January 25th, 2020

    Q1
    Cisco IP Phone Data Traffic
    The switch can also process tagged data traffic (traffic in IEEE 802.1Q or IEEE 802.1p frame types) from the device attached to the access port on the Cisco IP Phone (see Figure 14-1). You can configure Layer 2 access ports on the switch to send CDP packets that instruct the attached phone to configure the phone access port in one of these modes:
    •In trusted mode, all traffic received through the access port on the Cisco IP Phone passes through the phone unchanged.
    •In untrusted mode, all traffic in IEEE 802.1Q or IEEE 802.1p frames received through the access port on the Cisco IP Phone receive a configured Layer 2 CoS value. The default Layer 2 CoS value is 0. Untrusted mode is the default.
    Note: Untagged traffic from the device attached to the Cisco IP Phone passes through the phone unchanged, regardless of the trust state of the access port on the phone.
    https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2960/software/release/12-2_40_se/configuration/guide/scg/swvoip.pdf

  2. John2020
    January 26th, 2020

    Q:1 Certprepare answers are correct. Link below:

    https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3560/software/release/12-2_52_se/configuration/guide/3560scg/swvoip.html

    Before you enable voice VLAN, we recommend that you enable QoS on the switch by entering the mls qos global configuration command and configure the port trust state to trust by entering the mls qos trust cos interface configuration command. If you use the auto-QoS feature, these settings are automatically configured

  3. polleke
    February 6th, 2020

    B. All untagged traffic that arrives on the device is placed into the native VLAN. ==> Correct
    C. The VLAN tag is stripped from all incoming traffic that matches the native VLAN. ==> Correct
    D. They are propagated through VTP. ==> Wrong, VTP is propagated through the native VLAN.

  4. polleke
    February 6th, 2020

    Q10 add C: Unless “vlan dot1q tag native” is used.

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