CDP frame is a multicast. It is not a unicast/broadcast.
You can see this information from www.cisco.com
Rajesh
"[EMAIL PROTECTED]" wrote:
> I turned all debugging for CDP on and I am no seeing much? I don't have a
> sniffer.
>
> r2#sh cdp nei
> Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
> S - Switch, H - Host, I - IGMP
>
> Device ID Local Intrfce Holdtme Capability Platform Port ID
> r3 Eth 2/0 134 R 1000 Eth 0
> r4 Eth 2/1 124 R 2500 Eth 0
> r2#
>
> r2#debug cdp ?
> adjacency CDP neighbor info
> events CDP events
> packets CDP packet-related information
>
> r2(config-if)#
> CDP-AD: Interface Ethernet2/0 going down
> CDP-PA: Packet sent out on Ethernet2/0
> CDP-AD: Interface Ethernet2/0.1 going down
> CDP-PA: Packet sent out on Ethernet2/0.1
> CDP-AD: Interface Ethernet2/0.2 going down
> CDP-PA: Packet sent out on Ethernet2/0.2
> CDP-AD: Interface Ethernet2/0 going down
> CDP-PA: Packet sent out on Ethernet2/0
> CDP-AD: Interface Ethernet2/0.1 going down
> CDP-PA: Packet sent out on Ethernet2/0.1
> CDP-AD: Interface Ethernet2/0.2 going down
> CDP-PA: Packet sent out on Ethernet2/0.2
> %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet2/0, changed state
> to d
> CDP-EV: Encapsulation on interface Serial0/0 failed
> CDP-PA: Packet sent out on Ethernet2/1
> %LINK-5-CHANGED: Interface Ethernet2/0, changed state to administratively
> down
>
> r2(config-if)#no shut
> r2(config-if)#
> CDP-AD: Interface Ethernet2/0 coming up
> CDP-PA: Packet sent out on Ethernet2/0
> CDP-AD: Interface Ethernet2/0.1 coming up
> CDP-PA: Packet sent out on Ethernet2/0.1
> CDP-AD: Interface Ethernet2/0.2 coming up
> CDP-PA: Packet sent out on Ethernet2/0.2
> %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet2/0, changed state
> to
> CDP-AD: Interface Ethernet2/0 coming up
> CDP-PA: Packet sent out on Ethernet2/0
> CDP-AD: Interface Ethernet2/0.1 coming up
> CDP-PA: Packet sent out on Ethernet2/0.1
> CDP-AD: Interface Ethernet2/0.2 coming up
> CDP-PA: Packet sent out on Ethernet2/0.2
> %LINK-3-UPDOWN: Interface Ethernet2/0, changed state to up
>
> ----- Original Message -----
> From: "Priscilla Oppenheimer"
> To:
> Sent: Tuesday, June 26, 2001 4:45 PM
> Subject: Re: Is a CDP frame a broadcast, multicast or unicast? [7:10024]
>
> > At 06:21 PM 6/26/01, [EMAIL PROTECTED] wrote:
> > >Is a CDP frame a broadcast, multicast or unicast?
> >
> > Why don't you turn on debug or use an analyzer and find out for
yourself!?
> > :-) You would learn a lot.
> >
> > > The frame contains no
> > >source
> > >or destination.
> >
> > If it contains no destination, then why are you wondering if it is
> destined
> > to a broadcast, multicast, or unicast address?
> >
> > On LANs, it does contain a source (the router or switch that is sending
> the
> > info) and a destination, the Cisco multicast address 01:00:0C:CC:CC:CC.
> >
> > Perhaps the statement meant that on a point-to-point WAN link it doesn't
> > include a source and destination. That could be true.
> >
> > Priscilla
> >
> > > It consists of a header, followed by a set of variable-length
> > >fields consisting of type/length/value.
> > ________________________
> >
> > Priscilla Oppenheimer
> > http://www.priscilla.com
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