Need Help With DTP Configuration

[david.esposito01]

Hi folks, i needed some help with DTP configuration on my network that i’m working on. I just have not been able to get DTP to work and to be able to ping the other devices. The two base configs are linked below. I am trying to connect port fa0/14 from beijing switch to fa0/14 on shanghai switch. I was planning on using ‘switchport mode dynamic des’ then ‘switchport trunk native vlan 999’ on beijing switch and ‘switchport trunk native vlan 999’ on shanghai switch. I’m not really sure if any of this is correct but nothing i tried worked. If it helps here is a diagram of the setup

BeijingRTR ———BeijingSW———BeijingPC

                               |

                               |

ShanghaiRTR——ShanghaiSW——ShanghaiPC

Hopefully someone can help fix my mistakes haha.

[pieterh]

you need to configure link between switch and router as a trunk too! (both routers)

the router does not know about trunks, but uses subinterfaces to send vlan-tagged packets

the switchport does not negotiate the trunk with the router, it must be configured fixed trunk on the connected interface

(and don't forget to check the port is not shutdown)

depending on age of the device you may need to use crossed UTP cable between the two switches (if not auto MDI/MDI-X capable)

[david.esposito01]

how would i go about doing that? i thought i had the link manually configured as a trunk (from router to switch).

and they should be mdix capable. thanks for your help

[david.esposito01]

actually never mind. i figured it out lol. thanks so much for your help :3

[pieterh]

good to hear you got it working

Regards,

Pieter