Multi-vendor Network

Designing a hybrid network environment where Cisco Discovery Protocol (CDP) and Link Layer Discovery Protocol (LLDP) coexist securely.

Multi-vendor Network — TopologyInteractive

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Objective

To design and validate a multi-vendor network discovery environment where both Cisco Discovery Protocol (CDP) and Link Layer Discovery Protocol (LLDP) coexist without interference.
The goal is to keep Cisco-to-Cisco discovery zones separate from the multi-vendor interoperability zones.

Scenario Overview

In a mixed enterprise environment, not all devices support CDP.
Routers and switches that connect to Cisco equipment use CDP for detailed neighbor discovery, while ports facing third-party or open-standard devices use LLDP.
Setting it up per interface lets you control which protocol runs on which link and test how the two behave alongside each other.

Implementation Summary

Device	Cisco Zones (CDP)	Multi-Vendor Zones (LLDP)	Protocol Behavior	Notes / Purpose
Router1	e0/1, e0/2	e0/0, e0/3	CDP enabled on Cisco zones; LLDP transmit-only on multi-vendor links	Prevents overlap, shares link info with non-Cisco devices
Router2	e0/0, e0/2	e0/1, e0/3	CDP and LLDP separated by interface	Clean protocol boundaries, avoids duplicate discovery
Router3	----	All Ethernet ports (LLDP active)	LLDP transmit-only on e0/2; CDP active only on select Cisco links	Ensures full LLDP visibility, keeps backward Cisco compatibility
Switch1	e0/0, e0/1	e0/2 (receive-only)	CDP for Cisco links; LLDP limited to receiving on multi-vendor port	Acts as bridge between Cisco and multi-vendor zones
Switch2	—	e0/0–e0/3 (except e0/3 receive-only)	LLDP transmit/receive on all, CDP disabled	Pure LLDP environment for interoperability testing

Result

This topology cleanly divides discovery domains:

CDP zones: internal Cisco-to-Cisco connectivity
LLDP zones: external or third-party interoperability points

The result splits discovery cleanly: CDP stays inside the Cisco zones, and LLDP handles every link facing another vendor.

Topology DIAGRAM

Command On Each Device

Router1

Goal:
CDP on e0/1 & e0/2 (Cisco zone)
LLDP on e0/0 (Tx/Rx) and e0/3 (Tx only)

conf t
! --- Enable CDP globally
cdp run
! --- Enable LLDP globally
lldp run

! --- CDP-enabled interfaces
int e0/1
 cdp enable
 no lldp transmit
 no lldp receive
exit

int e0/2
 cdp enable
 no lldp transmit
 no lldp receive
exit

! --- Unused Port 
int e0/0
 no cdp enable
 no lldp transmit
 no lldp receive
exit
! --- LLDP-enabled interface
int e0/3
 no cdp enable
 lldp transmit
 no lldp receive
exit

Router2

Goal:
CDP on e0/0 & e0/2
LLDP on e0/1 & e0/3

conf t
cdp run
lldp run

! --- CDP zone
int e0/0
 cdp enable
 no lldp transmit
 no lldp receive
exit

int e0/2
 cdp enable
 no lldp transmit
 no lldp receive
exit

! --- LLDP zone
int e0/1
 no cdp enable
 lldp transmit
 lldp receive
exit

int e0/3
 no cdp enable
 lldp transmit
 lldp receive
exit

Router3

Goal:
CDP disabled Globally LLDP on all Ethernet ports (Tx/Rx), except e0/2 Tx only

conf t
no cdp run
lldp run

! --- LLDP on all Ethernet
int e0/0
 lldp transmit
 lldp receive
exit
! --- UNused Port
int e0/1
 no lldp transmit
 no lldp receive
exit

int e0/2
 lldp transmit
 no lldp receive
exit

int e0/3
 lldp transmit
 lldp receive
exit

! --- CDP kept for Serial interfaces in CML entering Serial interface of this device is not permit
int range s1/0 - 1/3
 no lldp transmit
 no lldp receive
exit

end
wr

Switch1

Goal:
CDP on e0/0 & e0/1
LLDP receive-only on e0/2

conf t
cdp run
lldp run

! --- Cisco zone (CDP)
int e0/0
 cdp enable
 no lldp transmit
 no lldp receive
exit

int e0/1
 cdp enable
 no lldp transmit
 no lldp receive
exit

! --- Multi-vendor receive-only LLDP
int e0/2
 no cdp enable
 no lldp transmit
 lldp receive
exit

! --- Disable LLDP entirely on e0/3
int e0/3
 no cdp enable
 no lldp transmit
 no lldp receive
exit

end
wr

Switch2

Goal:
CDP disabled Globally
LLDP on all interfaces (Tx/Rx), except e0/3 Rx-only

conf t
no cdp run
lldp run

! --- LLDP full Tx/Rx
int range e0/0 - 2
 no cdp enable
 lldp transmit
 lldp receive
exit

! --- LLDP Rx-only
int e0/3
 no cdp enable
 no lldp transmit
 lldp receive
exit

end

Summary Table

Device	CDP Interfaces	LLDP Interfaces (Tx/Rx)	Special Cases
Router1	e0/1, e0/2	e0/0 (Tx/Rx), e0/3 (Tx only)	–
Router2	e0/0, e0/2	e0/1, e0/3	–
Router3	e0/1 + Serial ports	e0/0, e0/1, e0/3	e0/2 Tx only
Switch1	e0/0, e0/1	e0/2 Rx only	–
Switch2	None	e0/0–e0/2 (Tx/Rx)	e0/3 Rx only

Download YAML File For CMLFile

Multi-vendor Network

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