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For questions about or involving the Cisco Discovery Protocol (CDP), where CDP displays information about the directly connected devices such as device ID, Platform, connected interface, IOS versions, and layer 3 IP address on Cisco network devices.

3
votes
5answers
375 views

Is there a Layer 2 address advertising protocol?

I needed help in understanding if LLDP/CDP is the Layer 2 equivalent to RIP or say any Layer 3 route advertising protocol. If not,is there a protocol that advertises the MAC Address Tables among ...
4
votes
2answers
521 views

Cisco CDP is dot1q native tagging required?

The only way the router could receive CDP advertisements over a switch trunk, was by creating a sub-interface on the router with "encapsulation dot1Q 1 native" configured. If this sub-if was ...
-1
votes
1answer
32 views

CDP Reveal question

1) does CDP reveal vlan ID, voice vlan ID, trunk native vlan ID?? Or only Vlan ID and voice vlan id? 2) Also what is native vlan and default vlan? Is there a simple explanation?
0
votes
1answer
754 views

Understanding how spanning-tree protocol (STP) works, along with CDP and DTP

I have made the following simple network model on packet-tracer consisting of two laptops and a switch. I don't do any configurations on laptops or switches, the only thing I do is connecting them ...
2
votes
3answers
1k views

Why do I get different serial number from “show version” than from “show inventory”

Once I'm connected via telnet to certain CISCO equipment I type "Show inventory" and I get to something like this: Barragan_3750>show inventory NAME: "1", DESCR: "WS-C3750G-12S" PID: WS-C3750G-12S-...
1
vote
2answers
679 views

Couldn't activate the CDP compatibility in the HP V1910 web interface

I tried to enable both LLDP and CDP from the web interface of my V1910 switch, but every time I select enable the session logs out. I found a command to enable the LLDP from the the switch's terminal. ...
1
vote
1answer
483 views

CDP/LLDP over LACP Trunk Several Devices

I have a 4-switch stack of Alcatel Omniswitches connected to an HP 5412 core via 8 uplinks; these are ports D11-D18. Unfortunately, the client did not yet give me access to the Alcatels, but a request ...
1
vote
2answers
1k views

Switchport security best practises for Cisco IP Phones (Not subjective)

I am having some trouble figuring out what the most secure method is to secure a Cisco IP Phone. I can't find information on how to properly secure the Link between a switchport and a Cisco IP Phone, ...
2
votes
1answer
416 views

CDP over Frame-Relay

[R1]---[FRSW]---[R2] - is the topology. Everything is L2, there are no PVC's, all physical interfaces. At startup everything is running with HDLC. Enable CDP - we get CDP neighbors across the board....
1
vote
1answer
321 views

Listen-only (stealth) CDP on IOS

I would like to put my router in a listen-only mode for CDP i.e. it should allow CDP packets to only arrive while not advertising so that I can glimpse into physical topology while remaining hidden to ...
3
votes
1answer
443 views

How to disable CDP on multiple sub-interfaces from physical bearer?

You can enable flow on the physical bearer and it will automatically add the flow configuration to any subsequent sub-interfaces using ip route-cache flow. Is there any way to disable/enable CDP on ...
11
votes
2answers
1k views

Syslog message for CDP interface down

I have been searching for this for a while and haven't found one yet. I need a Cisco IOS command to send a syslog message or snmp trap whenever an interface that has a CDP neighbor goes down. Some ...
9
votes
2answers
544 views

CDP not available to be enabled on ME3400 port

We have a ME3400 that we want to enable CDP on but there is no cdp option. Why is it not available? switch(config)#int gi0/1 switch(config-if)#cdp ? % Unrecognized command CDP is enabled globally. ...
9
votes
2answers
1k views

Brocade chassis and CDP

I know Brocade will gladly accept CDP from Cisco devices and display it in a show fdp neighbor. If you enable CDP on a Brocade chassis will it send CDP packets out as well as FDP?