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Network Guy
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reply to xdxml12

Re: CDP

If it's a Cisco shop, CDP could be useful in a topology where the previous network guy didn't bother keeping an updated Visio diagram somewhere, if at all.

Of course one would still want to physically spot-check what IOS is saying at the prompt, but it's still a good place to start.


nosx

join:2004-12-27
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4 edits

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Im not arguing with you cramer, im saying that your experience in the past 20 years does not match the experience of others.
Attached is a picture from vmware vsphere 5 running the standard vswitch with CDP information.
CDP is not only useful in a pure cisco network either, plenty of systems have been configured to add value through use of CDP:
C3750-A#show cdp nei g1/0/17 detail
-------------------------
Device ID: NEMESIS(SYSTEM)
Entry address(es): 
  IP address: 3.1.0.50
Platform: MEM: All=16382M,  Capabilities: Host 
Interface: GigabitEthernet1/0/17,  Port ID (outgoing port): Intel(R) PRO/1000 EB Network 
Holdtime : 29 sec
 
Version :
CPU:8*586 Intel(R) Xeon(R) CPU           E5410  @ 2.33GHz
Microsoft Windows Server 2003 R2, Enterprise x64 Edition Service Pack 2 (build 3790)
DISK INFORMATION:
C:\ : Fixed Disk
D:\ : CDROM Disk
W:\ : Fixed Disk
 
advertisement version: 2
Management address(es): 
 
In a datacenter with 7000+ hosts you dont have to worry about shutting down a port or tracing a cable to figure out which host and interface its plugged into.
Link layer discovery can be worth its weight in gold from an operational support perspective.
Also, CDP is only locally significant traffic. A CDP frame from a host is not flooded throughout an entire VLAN, so no need to slay another little broadcast "vampire".


Paulg
Displaced Yooper
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join:2004-03-15
Neenah, WI
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What software are you using for a windows box to speak CDP?

As a VMWare guy, CDP is incredibly useful.


cramer
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join:2007-04-10
Raleigh, NC
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reply to nosx

All I can say is none of my VMware servers appear in the switch's CDP neighbors. (they've all been boxed for an office move)

Actually, it's multicast -- broadcast for dumber swithces. And it does, indeed, flood through a network that doesn't understand what it is. (esp. for any network set to flood unknown multicast.)



Paulg
Displaced Yooper
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join:2004-03-15
Neenah, WI
kudos:1

esxcfg-vswitch -B both [VSWITCHNAME]