trunking on ip phone ports?

Discussion in 'Cisco' started by P, Oct 17, 2003.

  1. P

    P Guest

    Hi

    I have seen lots of examples of ip phone ports set up like this..

    interface FastEthernet0/4
    switchport trunk encapsulation dot1q
    switchport trunk native vlan 150
    switchport mode trunk
    switchport voice vlan 200
    spanning-tree portfast
    end

    and this is kind of what I expected, whan having no experience in VOIP,
    assumed that an ip phone would have to trunk if it was also handling a PC in
    a different VLAN.

    But when I read the "Configuring Voice VLAN" section of the IOS docco, I
    don't recall it making references to this need, and in fact CDP is used to
    handle the phone.

    Thus is this perfectly valid?

    interface FastEthernet0/4
    switchport access vlan 150
    switchport voice vlan 200
    spanning-tree portfast
    end

    I occasionally get the phones obtaining a DHCP address from VLAN 150, rather
    than 200. Would this be some breakdown in the CDP negotiation between
    phone->switch?

    Anybody seen this before?
     
    P, Oct 17, 2003
    #1
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