trunk port

[suthomas1]

Hello,
We have this network , where access points are all connected via a small
non-cisco basic switch(in a workshop enviornment) which only seems to have basic vlan & port setting.
these small switches are linked to a cisco switch , cisco end port is a trunk port.
vlans 21,22 & 23 are defined on cisco switch and are the ones that get connected to main office from remote workshop.
should the small switces also have vlan 21,22 & 23 defined on them or will this work if the small switches uplink
port to cisco switch be just set as trunk instead of access.

[Andrew Khalil]

@suthomas1,

Greetings,

All ports that are connected from the cisco managed switch to a non managed switch should be in access mode, otherwise it will not work! simply because when the link is trunk, it will tag the packets with the vlans ID, while the unmanaged switch hasn't the ability to remove the vlan ID and give it to the meant port! except if the vlan is default, so it will not be tagged at all! 

To make a specific port in an access mode: 

#switchport mode access

#switchport access vlan x

#no shutdown

Please, don't forget to rate helpful responses and mark solutions,

Bst Rgds,

Andrew Khalil

[romanroma · Accepted solution]

You might want to see if the non-cisco switch supports 802.1q. If it does, then you might be able to configure a trunk port on your non-cisco device.

The configuration might be different, and you will have to understand (1) what you want tagged, and (2) what you don't want tagged. For example: HP label their 802.1q concepts a little different then Cisco.

However, the main take away is see if the switch in question supports 802.1q.

In addition, the switch in question might not support the VTP data base, so there maybe a possibility that if you supply the VLAN number on the other switches, the tagging will work. Treat it as if the switch is in Transparent mode for VTP as in the VTP domain topology concept; however, you might want to play with this in a lab type environment.

[suthomas1]

Thanks.

One of my colleagues who is on this site, has indicated that the non-managed switch does have the option of access & trunk on its port setting.Now given this, if we just set the uplink to trunk & all vlan will this work?

[Andrew Khalil]

@suthomas1,

Greetings,

As I said before, if you configured that link to trunk, non of the vlan will be accessed by this non managed devices, 

the only solution is to configure it as an access port, and this means that only ONE vlan will be accessed by the non managed switches!

Please don't forget to rate helpful responses and mark solutions!

Bst Rgds,

Andrew Khalil

[ngkin2010]

HI,

If more than one VLANs are used in the small switch (the non-cisco switch), you must set the up link to be trunk link, so that it could carry multiple VLAN tagged packet over the trunk link.

[romanroma]

It will carry all vlans across the Trunk port; however, you still might have to create the vlans locally on the non-cisco switch, since this switch is not participating in the VTP domain.

Note.... remember - you would still have to perform routing some where within your topology. That can be at a router/switch or a firewall depending on how your network is configured.