Ken Spickler
Sent from iPhone. Srry for tpos.
sure this is old news for most, but I've found this to be useful.
cisco has a layer 2 protocol that allows you to see end devices
before line protocol comes up (typically IP) called CDP, LLDP is
the open equivalent to it.
there is a project (one of a few i found) openlldp which will
compile without issue on osx and linux (probably windows too).
anyway it allows you to see hosts on the other end of a link/port
which can be useful when trying to answer the question "what is
plugged into port 3/4 on that switch?". And you can do this without
the other end being IP'd, or IP'd incorrectly, or misconfigured
( LACP to non LACP port for example). as long as the interface is up.
take care and have a great weekend,
greg
see the output below, commands issued from one of our routers..
osx-gwhynott:~ gwhynott$ ssh core0
Password:
*
This is:
CORE0.
OICR.ON.CA June
2009
*
COREROUTER>show lldp neighbors
Capability codes:
(R) Router, (B) Bridge, (T) Telephone, (C) DOCSIS Cable Device
(W) WLAN Access Point, (P) Repeater, (S) Station, (O) Other
Device ID Local Intf Hold-time Capability Port ID
GFDCHPC Te6/2 120 B,R 3
GFDCHPC Te6/1 120 B,R 1
dist5 Te3/5 120 B 265
GFDC Te3/7 120 B,R 1
GFDC Te3/8 120 B,R 3
6SR_C1_SHAKEY Te5/5 120 B,R 49
sl-e1200 Gi5/1 120
GigabitEthernet 0/10
apc-sw0 Gi9/12 120 B 50
6thDIST Te3/6 120 B 1
6SR_CORE2_DUSTY Te5/4 120 B 241
osx-gwhynott Gi5/41 120 RS en0
Total entries displayed: 11
COREROUTER>show lldp neighbors gigabitEthernet 5/41 detail
Chassis id: 0017.f20a.ba72
Port id: en0
Port Description:
System Name: osx-gwhynott.res.oicr.on.ca
System Description:
QTSS/6.0.3 (Build/526.3; Platform/MacOSX; Release/Darwin Streaming
Server; State/Development; )
Time remaining: 118 seconds
System Capabilities: S,R
Enabled Capabilities:
Management Addresses:
IP: 10.10.10.10
Auto Negotiation - supported, enabled
Physical media capabilities:
Other/unknown
Symm Pause(FD)
Symm, Asym Pause(FD)
Media Attachment Unit type:
Total entries displayed: 1
COREROUTER>
_
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