My Question has two parts

1). I would like to know Can a Access Port be part of two different VLAN'S?

2). Also say how can a member(node) of one VLAN(V10) connected to Switch(s1) through access port communicate with member(node) of same VLAN(V10) connected to Switch(s2) through Trunk port . Switch(s1) and Switch(s2) are connected each other through a trunk port

How above it happen?

  • What business solution are you trying to offer with this configuration? VoIP phones? Something else? Jul 26, 2012 at 16:24
  • I'm just trying to understand how things work under VLAN
    – AMIT
    Jul 26, 2012 at 17:31
  • Then you might be interested in this response Jul 26, 2012 at 17:40

2 Answers 2


1) An access port will ingress untagged traffic and place it on the default VLAN, or whatever VLAN you set it to. Traffic bound for MAC addresses on that same port is egressed untagged as well. If you want TWO VLANs to be accessible on that port, you can configure it as a trunk and assign both VLANs to the port and the downstream device will need to be able to make use of VLAN tagging. Additionally, you can set the "native" VLAN on the port so that it will also still accept untagged traffic. Most servers and NIC drivers support VLAN tagging, so it's perfectly fine to do this. Some switch manufacturers DO permit you to leave the port configured as an "access" port and also allow tagged traffic. This achieves the same result as configuring it as a trunk. It can be quite confusing because they sometimes change terminology.

2) If the link between the switches is configured as a trunk, and either allows all VLANs or allows those specific VLANs, then all you need to do is configure either access or trunk ports onto that VLAN and things should work properly.

  • Thanks for your explanation @Spiff but if tagged frame comes at access port conversion do take place (tagged info removed from frame) and if access port sends a frame to truck port there also conversion takes place (tagged info is added there),am I right?
    – AMIT
    Jul 27, 2012 at 5:40
  • If an tagged packet hits an acccess port, the tag will be stripped off. If that same now untagged packet hits a trunk port that has a "native" VLAN set on the port, the trunk will usually drop the untagged packet into the native VLAN. This may all work the way you "want". But it's bad/confusing design.
    – Rex
    Jul 27, 2012 at 6:15
  • Thanks Rex for your response and it help me a lot . Can I have some docs where this "native VLAN" this is mentioned out.
    – AMIT
    Jul 27, 2012 at 11:35
  • It's in the admin guide for whatever hardware your using, go to the manufacturer's website and download it there. Jul 27, 2012 at 13:19
  1. No, an access port can only be part of one VLAN.
  2. The trunk ports on the two switches need to be configured to forward the VLAN 10 packets, then all hosts on all VLAN 10 access ports will be able to communicate.
  • Thanks @Oliver Why access port is part of one VLAN only?
    – AMIT
    Jul 26, 2012 at 15:49
  • That's pretty much the definition of an access port, its meant for devices that do not understand VLAN tags, therefore it puts untagged traffic onto the default VLAN or whatever VLAN you set it to. Either way, the conversation happens without tags on the ethernet frame. Jul 27, 2012 at 0:50
  • @AMIT if you were able to put an access port in multiple VLANs, you would basically join these VLANs to a single VLAN in which case you wouldn't need the VLANs to be separate.
    – Oliver
    Jul 27, 2012 at 7:54
  • @Oliver - To clarify, when should an access port be used and when should a trunk be used? My understanding is that an access port is to support the communication between a router or switch to a device such as a PC or printer that does not supporting tagging. A trunk is used when a port on a router or switch is configured to support multiple VLAN tags. The port is connected with another router or switch.
    – Motivated
    Oct 27, 2019 at 2:45
  • @Oliver - What occurs when a port is configured to be an access port and a device that supports tagging is connected to it? Equally,what occurs when a device that does not support tags is connected to a trunk?
    – Motivated
    Oct 27, 2019 at 2:45

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