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Which feature should be enabled?

An administrator wishes to enable network port mirroring based on source port. Which feature should be
enabled?

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A.
vSphere standard switch port

B.
ERSPAN

C.
NSX Virtual Wire

D.
VLAN

Explanation:
Enter a valid VLAN ID in the field. This information is required for Remote Mirroring Source port mirroring
sessions.
https://docs.vmware.com/en/VMware-vSphere/6.5/com.vmware.vsphere.networking.doc/GUID-
81309F10-D7FF-447C-9D35-58CA3DDA53B1.html

16 Comments on “Which feature should be enabled?”

    1. genjam.bhai says:

      B is correct.

      To allow port mirroring, one does not need to “enable” a VLAN. Instead you need to specify the Port Mirroring Session Type, one of which is Encapsulated Remote Mirroring (L3) Source aka ERSPAN.

      https://docs.vmware.com/en/VMware-vSphere/6.5/com.vmware.vsphere.networking.doc/GUID-C3970893-9328-430C-A440-F22B7E26280A.html

      Also, to clear doubt you need to “Specify the source VLAN” if you selected a Remote Mirroring Destination sessions type, you must specify the source VLAN,
      but question asks for Source Port Mirroring.

      https://docs.vmware.com/en/VMware-vSphere/6.5/com.vmware.vsphere.networking.doc/GUID-79E7AB5B-A6A9-4F9B-A253-3E32A086F170.html




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      1. genjam.bhai says:

        ERSPAN needs a specific vlan for the mirrored traffic to traverse through. This vlan needs to be enabled on physical switches not in vSphere. So again, B is correct.

        “Enter a valid VLAN ID in the field. This information is required for Remote Mirroring Source port mirroring sessions.”




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  3. hnmurugan says:

    Answer : D
    The question states as in “Which feature should be enabled?”. I doubt there is a setting available in GUI of vCenter to enable “ERSPAN”, so i think the answer is D.




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  4. Youngster345 says:

    A VLAN would only need to be ‘enabled’ for the Remote Mirroring Destination type of port mirroring, which is based on VLANs. It explicitly calls out mirroring based on source port, invalidating that as the correct answer.

    NSX and standard switch ports are also invalid options for port mirroring, so ERSPAN is the only possible correct answer.

    https://docs.vmware.com/en/VMware-vSphere/5.5/com.vmware.vsphere.networking.doc/GUID-C3970893-9328-430C-A440-F22B7E26280A.html




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    1. Youngster345 says:

      Nevermind, further reading revealed that a VLAN ID is needed for encapsulating source port mirroring.

      “Enter a valid VLAN ID in the field. This information is required for Remote Mirroring Source port mirroring sessions.

      Mark the check box next to Preserve original VLAN to create a VLAN ID that encapsulates all frames at the destination ports. If the original frames have a VLAN and Preserve original VLAN is not selected, the encapsulation VLAN replaces the original VLAN.”

      Also, based on my reading true ERSPAN needs an additional module such as ExtraHop so it is not a feature to be ‘enabled’ in vSphere.

      https://docs.vmware.com/en/VMware-vSphere/6.5/com.vmware.vsphere.networking.doc/GUID-81309F10-D7FF-447C-9D35-58CA3DDA53B1.html




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  5. interzoid says:

    The wording of question is horrible (VLAN is not a “feature”), but I believe the answer is D.
    In vSphere 6.5 there are two possible mirroring methods based on source port: “Remote Mirroring Source” and “Encapsulated Remote Mirroring (L3) Source”)
    For Remote Mirroring Source you need to specify a VLAN ID to mirror.
    For Encapsulated Remote Mirroring (L3) Source you need to specify an encapsulation type (GRE or ERSPAN).
    Since question does not mention “Encapsulated mirroring” I believe it’s referring to simple Remote Mirroring Source method, so VLAN is the right answer.
    It’s D then.




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  6. vcpd says:

    Yet another question with a confusing wording, wonder if it’s the same in the exam..
    VLAN isn’t a VMware feature, so I would exclude it.
    Also, as per VMWare documentation: “If you selected a Remote Mirroring Destination sessions type, you must specify the source VLAN. “.
    When you set a Remote mirroring Source type from the GUI, it asks to choose a VLAN just to send the traffic with, with the option to retain or not the original VLAN.
    When you set Destination, it will ask which VLAN you want to mirror.

    In both cases, you set the VLAN as part of ERSPAN configuration.

    So, I would say ERSPAN, as it is a feature, which may require a VLAN as part of the configuration.




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      1. vcpd says:

        ERSPAN mirrors traffic on one or more “source” ports and delivers the mirrored traffic to one or more
        “destination” ports on another switch. vSphere 6.5 includes support for the ERSPAN protocol.




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