Should I see the CSR1000V's as CDP neighbors?


If I setup two CSR1000Vs on VMware and give each router a dot1q sub-interface of say vlan 100 - should they see each other as CDP neighbors? 

Does the VMware vSwitch work more like a real switch or a hub?




  • If you set up the vswitch correctly, you should see them as cdp neighborings via their physical interface, not the sub-interface. 

  • You need to modify the vSwitch properties to enable promiscuous operation for both the NIC that supports the vSwitch and vSwitch itself..  Also don't forget to set the vlans setting to allow all vlans on the NIC.

  • CDP is disabled globally and at the interface level by default on CSR1000v.


    Enable with:


    conf t

    cdp run

    int ...

    cdp enable


  • fc2462fc2462 ✭✭


    I did setup my vSwitch in promiscuous mode and have confirmed because I have a Wireshark VM and I can see traffic from all the routers on the Wireshark port.

    I also discovered that CDP was disabled on the 1000V by default and fixed that.

    But I still can't see the 1000V as neighbors.

    Any ideas what else to check?



  • Are you doing trunking/sub-interfaces? Or just IP addressing on the main interface?


    Could you provide running-config and 'sh cdp interface' outputs?

  • fc2462fc2462 ✭✭


    OK, got it now.  I needed to enable CDP on the sub-interface as well.  Now it's working.

    csr1#sh cdp nei
    Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                      S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone,
                      D - Remote, C - CVTA, M - Two-port Mac Relay

    Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
    csr2             Gig 1.100         139              R I   CSR1000V  Gig 1.100

    Total cdp entries displayed : 1

    I wonder why CDP is completely disabled by default on these 1000Vs?

    Thank you,


  • As per:



    "CDP is not enabled by default on Cisco Aggregation Services Routers (ASRs) or on the Cisco CSR 1000v."


    I guess this make sense for the CSR1000v as 95%+ of the interfaces (in a real topology - not a home CCIE lab) will be host facing so security wise it's safer for the default to be disabled.


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