To use Access or Trunk mode on a port?

[danielgarcia15 (dangar)]

Hi all,

I am in need of some help with the correct VLAN mode to use on a port. I have some small business cisco switches that out of the box have all ports using Trunk mode.

Here is a switch that only has PCs connected to it (except GE26, that is a switch). Is this correct or should they be Access mode?

I have a very simple network setup. Without getting too complicated is this the correct way?

Any help is much appreciated.

[aarondeane]

Trunks carry multiple vlans where access ports carry only one vlan. All PC’s should be on access ports where switches should be on trunk ports. Hope this helps.

[dimforest (ᴅɪᴍꜰᴏʀᴇsᴛ)]

@aarondeane

Trunks carry multiple vlans where access ports carry only one vlan. All PC’s should be on access ports where switches should be on trunk ports. Hope this helps.

Pretty much this. There are some exceptions here and there but generally, yes - devices on access ports and switches on trunks.

[joshmecahm (Josh_the_Geek)]

@aarondeane

Trunks carry multiple vlans where access ports carry only one vlan. All PC’s should be on access ports where switches should be on trunk ports. Hope this helps.

Trunk Can mean a kind of Port Aggregation on some devices, be careful and be sure to check before you implement it.

[craigthomas6]

The Trunk config you show in your screenshot would provide identical functionality to having all those as Access ports in VLAN3.
A Trunk port which is untagged for PVID 3 works the same as an Access port in VLAN3, from the point of view of a normal PC.

The Trunk config you show could then easily be modified for VoIP phones by adding the Voice VLAN ID to each of these ports.

[igormeg]

@dimforest

@aarondeane

Trunks carry multiple vlans where access ports carry only one vlan. All PC’s should be on access ports where switches should be on trunk ports. Hope this helps.

Pretty much this. There are some exceptions here and there but generally, yes - devices on access ports and switches on trunks.

How are devices identified as to whether they should be on access ports or not?

[igormeg]

@craigthomas6

The Trunk config you show in your screenshot would provide identical functionality to having all those as Access ports in VLAN3.
A Trunk port which is untagged for PVID 3 works the same as an Access port in VLAN3, from the point of view of a normal PC.

The Trunk config you show could then easily be modified for VoIP phones by adding the Voice VLAN ID to each of these ports.

Let’s assume that I have a 4 port router or switch labelled ports 1 to 4.

The device is configured with the following VLANs

• VLAN 10
• VLAN 20
• VLAN 30
• VLAN 40

Each port is then assigned a VLAN as follows;

• VLAN 10 → Port 1
• VLAN 20 → Port 2
• VLAN 30 → Port 3
• VLAN 40 → Port 4

Each port is then assigned as an access port as follows;

• VLAN 10 → Port 1 → Access port

• VLAN 20 → Port 2 → Access port

• VLAN 30 → Port 3 → Access port

• VLAN 40 → Port 4 → Access port

If I subsequently update VLAN 40 and Port 4 to a trunk port which is connected to a PC via ethernet, do you mean to say that the PC would simply ignore the VLAN tag and treat the communication as untagged.