RE: trouble understanding L2 protocol tunneling

From: Todd, Douglas M. (DTODD@PARTNERS.ORG)
Date: Thu Apr 12 2007 - 14:58:56 ART


Ah - Cool.

Sure enough I have the configuation running, like yours so I does not seem to be
the configuration. It's acting like the system things that there is a shutdown
threshhold. I would assume that the sh l2protocol-tunnel summary states that
this is not configured. So you could 1) disable the error-l2protocol feature
(good for the testing but not good for the lab or production)
2) Reboot the hardware and see if the problem goes away (it's an idea)
3) Possible problems with hardware or cabling? Have you tried this on a
different set of switches or ports?
4) This problem only happens when you hard set it to dot1q, but does not happen
when you use isl or leave at the port at negotiate etc?

Just some ideas to try...

DMT

________________________________

From: Ronnie Angello [mailto:ronnie.angello@gmail.com]
Sent: Thursday, April 12, 2007 1:25 PM
To: Todd, Douglas M.
Cc: udo; dampened; ccielab@groupstudy.com
Subject: Re: trouble understanding L2 protocol tunneling

...Yes but the ports configured for the l2 protocol tunnel are in access mode.
The trunk link in between the switches is independent of that and can be
configured any which way.

On 4/12/07, Todd, Douglas M. <DTODD@partners.org> wrote:

        Hi;
        
        I can get this to work fine, the only thing which may cause you problems
is DTP:
        CCO:
        The switch does not support Layer 2 protocol tunneling on ports with
switchport
        mode dynamic auto or dynamic desirable.
        *DTP is not compatible with layer 2 protocol tunneling.
        
        In my config I must use switchport nonegotiate this will disable DTP on
the
        port. DPT is enabled on the trunk port still (sh int swi | b 0/13) -
        
        
        DMT
        -----Original Message-----
        From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Ronnie
        Angello
        Sent: Thursday, April 12, 2007 8:51 AM
        To: udo
        Cc: dampened; ccielab@groupstudy.com
        Subject: Re: trouble understanding L2 protocol tunneling
        
        R1 is connected to vlan 20 via CAT2 fa0/1. R2 is connected to vlan 20
via
        CAT1 fa0/2. There is a dot1q trunk between CAT1 fa0/13 and CAT2 fa0/13.
        
        
        CAT1#s run int fa0/2
        Building configuration...
        
        Current configuration : 138 bytes
        !
        interface FastEthernet0/2
        description R2
        switchport access vlan 20
        switchport mode access
        l2protocol-tunnel cdp
        no cdp enable
        end
        
        CAT1#
        
        CAT1#s run int fa0/13
        Building configuration...
        
        Current configuration : 113 bytes
        !
        interface FastEthernet0/13
        description cat2
        switchport trunk encapsulation dot1q
        switchport mode trunk
        end
        
        CAT1#s int trunk
        
        Port Mode Encapsulation Status Native vlan
        Fa0/13 on 802.1q trunking 1
        
        
        
        
        CAT2#s run int fa0/1
        Building configuration...
        
        Current configuration : 138 bytes
        !
        interface FastEthernet0/1
        description R1
        switchport access vlan 20
        switchport mode access
        l2protocol-tunnel cdp
        no cdp enable
        end
        
        CAT2#
        
        CAT2#s run int fa0/13
        Building configuration...
        
        Current configuration : 113 bytes
        !
        interface FastEthernet0/13
        description cat1
        switchport trunk encapsulation dot1q
        switchport mode trunk
        end
        
        CAT2#s int trunk
        
        Port Mode Encapsulation Status Native vlan
        Fa0/13 on 802.1q trunking 1
        
        R1#s cdp ne
        Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                         S - Switch, H - Host, I - IGMP, r - Repeater
        
        Device ID Local Intrfce Holdtme Capability Platform Port
ID
        R2 Fas 0/0 162 R S I 2610XM Fas
0/0
        R1#
        
        R2#s cdp ne
        Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                         S - Switch, H - Host, I - IGMP, r - Repeater
        
        Device ID Local Intrfce Holdtme Capability Platform Port
ID
        R1 Fas 0/0 148 R S I 2610XM Fas
0/0
        R2#
        
        
        On 4/12/07, udo < ccie_ka@arcor.de <mailto:ccie_ka@arcor.de> > wrote:
>
> hi,
>
> plz can you share the working config ?
> I also tried this but it doesn't work...
>
> thx
>
> Am Dienstag, den 03.04.2007 , 09:46 +0800 schrieb dampened:
> > Thank you for the clarification. Ronnie.
> >
> >
> >
> > ----- Original Message -----
> > From: Ronnie Angello
> > To: dampened taker
> > Cc: ccielab@groupstudy.com
> > Sent: Monday, April 02, 2007 9:48 PM
> > Subject: Re: trouble understanding L2 protocol tunneling
> >
> >
> > It should not be a problem to have trunk links between the
> switches. Only
> > the ports connected to R3 and R5 need to be access or .1q tunnel
> > ports
> to
> > support l2 protocol tunneling.
> >
> >
> >
> >
> > On 4/2/07, dampened taker <cheechew@hotmail.com> wrote:
> > But the problem with dot1q is between SWA and SWB.
> > Will dot1q between switches will cause problem?
> >
> >
> >
> >
> >
> >
> > From: "Ronnie Angello" < ronnie.angello@gmail.com
<mailto:ronnie.angello@gmail.com> >
> > To: dampened <cheechew@hotmail.com>
> > CC: "Cisco certification" < ccielab@groupstudy.com
<mailto:ccielab@groupstudy.com> >
> > Subject: Re: trouble understanding L2 protocol tunneling
> > Date: Mon, 2 Apr 2007 08:05:04 -0400
> >
> > The switch supports tunneling of CDP, STP, including multiple
> > STP
> (MSTP),
> > and VTP. Protocol tunneling is disabled by default but can be
> enabled for
> > the individual protocols on IEEE 802.1Q tunnel ports or on
> > access
> ports.
> >
> > Tunneling is not supported on trunk ports. If you enter the
> > *l2protocol-tunnel
> > *interface configuration command on a trunk port, the command is

> > accepted,
> > but Layer 2 tunneling does not take affect unless you change the
> port to
> > a
> > tunnel port or an access port.
> > Ronnie
> >
> > On 4/2/07, dampened <cheechew@hotmail.com> wrote:
> > >
> > >Dear Josef,
> > >
> > >Which part of the document states it cannot work with dot1q?
> > >
> > >It would be strange if the interconnect switch is unable to
> > support dot1q.
> > >
> > >Regards
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > "Josef A" <josefnet@gmail.com>
> > > Sent by: nobody@groupstudy.com
> > > 03/28/2007 06:43 PM Please respond to
> > > "Josef A" josefnet@gmail.com
> > >
> > >
> > >
> > >
> > >Layer 2 protocol tunnelling only works with access ports or
> > tunnel
> ports.
> > >
> > >
> > >
> http://www.cisco.com/univercd/cc/td/doc/product/lan/cat3560/12225see/s
<http://www.cisco.com/univercd/cc/td/doc/product/lan/cat3560/12225see/s>
> cg
> > /swtu
> > >nnel.htm
> > >
> > >
> > >
> > >On 3/27/07, Swan, Jay <jswan@sugf.com > wrote:
> > > >
> > > > I have the following physical topology:
> > > >
> > > >
> > > >
> > > > R3---SwA---SwB---R5
> > > >
> > > >
> > > >
> > > > R3 and R5 are in access vlan 35 with "l2protocol-tunnel cdp"
> > on
> the
> > > > access ports.
> > > >
> > > >
> > > >
> > > > If I configure the link between SwA and SwB in access vlan
> > 35
> with
> > > > "l2protocol-tunnel cdp", everything works fine: R3 and R5
> > see
> each
> > other
> > > > as directly connected CDP neighbors. If I configure the link
> between
> > SwA
> > > > and SwB as a hard-coded 802.1q trunk, however, the link is
> > err-disabled
> > > > with an l2ptguard error.
> > > >
> > > >
> > > >
> > > > I don't understand why this doesn't work with a trunk link.
> Thoughts?
> > > >
> > > >
> > > >
> > > > Jay
> > > >
> > > >
> >



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