[c-nsp] Strange ethernet frames on switch client ports

[Piltrafilla]

Steinar and Adrian,

I think I could live with those frames. Just wanted to know if they
belang to any protocol I did not disable. ;)

I think i'd better keep the keepalive setting.

Thank you to both and best regards,


On Fri, 19 Nov 2004 11:21:33 +0200, Adrian Pirciu
<adrian.pirciu at rdsnet.ro> wrote:
> These are special Ethernet defined for loopback test: (type 9000 hex).
> As you can see, the source and destination macs are the same. This
> special type of packet helps the switch notice if any layer1 loop
> forms, the moment when it receives the packet transmitted on the same
> port (it disables the port when this happens, unless the protection is
> disabled). I don't know if you cand disable this (maybe using
> err-disable loopback something) but it is possible that the packets
> will still be sent. .
> 
> 
> 
> On Friday 19 November 2004 10:52, Piltrafilla wrote:
> > Hi people,
> >
> > I am trying to completely clean up management frames on client ports
> > applying best common practices such as BPDU filtering
> >
> > interface FastEthernetX/Y
> >  switchport access vlan NN
> >  switchport mode access
> >  no ip address
> >  no cdp enable
> >  spanning-tree portfast
> >  spanning-tree bpdufilter enable
> >  spanning-tree bpduguard enable
> >  spanning-tree guard root
> > !
> >
> > This config removes 802.1d BPDUs, CDP frames, etc but on that port I
> > still see this management frames. I can't find which feature I must
> > disable in order to avoid them:
> >
> > 09:39:26.970184 0:f:90:fd:97:85 0:f:90:fd:97:85 9000 60:
> >                          0000 0100 0000 0000 0000 0000 0000 0000
> >                          0000 0000 0000 0000 0000 0000 0000 0000
> >                          0000 0000 0000 0000 0000 0000 0000
> > 09:39:36.975274 0:f:90:fd:97:85 0:f:90:fd:97:85 9000 60:
> >                          0000 0100 0000 0000 0000 0000 0000 0000
> >                          0000 0000 0000 0000 0000 0000 0000 0000
> >                          0000 0000 0000 0000 0000 0000 0000
> > 09:39:56.975158 0:f:90:fd:97:85 0:f:90:fd:97:85 9000 60:
> >                          0000 0100 0000 0000 0000 0000 0000 0000
> >                          0000 0000 0000 0000 0000 0000 0000 0000
> >                          0000 0000 0000 0000 0000 0000 0000
> >
> > MAC address belongs to the switch as show mac-address-table says.
> >
> >    All    000f.90fd.9785    STATIC      CPU
> >
> > Anyone can give me some light on that? :)
> >
> > Thank you in advance,
> > _______________________________________________
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> 
> --
> ------------------------------------------------------------------------
> Adrian Pirciu
> Network Engineer
>