[c-nsp] CDP -- more than one neighbor on the same port?
Furnish, Trever G
TGFurnish at herffjones.com
Wed Dec 12 13:58:07 EST 2007
Under what circumstances would CDP show more than one neighbor on the
same port?
We have a site where the local IT staff is claiming that a switch
interface (switch2 g0/2) is connected directly to exactly one other
cisco switch, but 'show cdp nei' on switch 2 shows three other switches
as neighbors on that interface.
LewSw2#show cdp nei g0/2
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
LewSw8.hj-int Gig 0/2 145 T S WS-C3508G-Gig
0/8
LewSw1.hj-int Gig 0/2 126 T S WS-C3548-XGig
0/1
LewSw12 Gig 0/2 156 S I WS-C3550-1Gig
0/11
Am I correct in assuming that this should only happen if the g0/2 port
is connected to a hub?
I realize CDP's not supposed to traverse switches, although I'm not
quite sure *why*. The destination's always 01000ccccccc, but I'm not
quite clear why such a frame wouldn't be flooded by a non-cdp-aware
switch.
--
Trever Furnish, tgfurnish at herffjones.com
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