Mode trunk

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Mode trunk

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Mode trunk
Mode trunk
2019-05-12 08:05:04
Hardware Version: V3
Firmware Version:

Hello,

 

Yesterday I've installed a new switch T2600G-28TS but I was not able to change mode trunk for a dedicated port...

 

It seems that this option was removed from the new software version.

 

However I was able to do that after a downgrade with V2 firmware.

 

This situation is not acceptable !

 

 

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#1
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10 Reply
Re:Mode trunk
2019-05-13 08:47:04

Yeah, tp-link changed their firmware design for some functions, so regarding your question now switches with new fw design don't support access/general/trunk port modes, while you still can use only general port mode, which should be fine for you.

If you need access (vlan 2 as example) -> use switchport general allowed vlan 2 untagged, switchport pvid 2, no switchport general allowed vlan 1

if you need trunk -> use switchport general allowed vlan 2-10 tagged

 

I also do not like it, but it is the future of tp-link switches.

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#2
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Re:Mode trunk
2019-05-15 03:37:31

About the trunk port, I remember that the packets will be untagged if the VLAN ID is equal to PVID. 

 

For example, if the PVID is 1, the outgoing packets of VLAN 1 will be untagged. If use general port to set up, remember to set up the untagged port.

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#3
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Re:Re:Mode trunk
2019-05-16 16:31:31

This new system has me very confused...

So on every dedicated VLAN port you need to do "no switchport general vlan allowed 1"?

I'm also confused about the use of PVID, is it obligatory to configure or not?
I've been wanting to apply VLAN's on a T1600G-28TS and I've read the documentation but it is limited in it's examples imo.

 

If I have 3 VLANS (7,8,9) and VLAN 1 I assume you would go about configuring this in CLI like this? =>
VLAN 8 being a voice vlan, i've applied the configuration from the manual but haven't had the chance to test it yet.
This is what I've got so far:
interface gigabitEthernet 1/0/2
switchport mode general
switchport general allowed vlan 7,8,9 tagged
speed 1000
no shutdown
interface range gigabitEthernet 1/0/7-11
switchport voice vlan mode manual
switchport voice vlan security
switchport general allowed vlan 8 untagged
switchport PVID 8
no shutdown
interface range gigabitEthernet 1/0/15-20
switchport mode general
switchport general allowed vlan 9 untagged
switchport PVID 9
speed 1000
no shutdown

 

With port 2 being the trunk port, now what confuses me is how do I apply the PVID to port 2 as there are multiple VLAN's present.
Is this anywhere near correct?

Thanks in advance

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#4
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Re:Re:Re:Mode trunk
2019-05-17 02:53:47

zerat wrote

This new system has me very confused...

So on every dedicated VLAN port you need to do "no switchport general vlan allowed 1"?

I'm also confused about the use of PVID, is it obligatory to configure or not?
I've been wanting to apply VLAN's on a T1600G-28TS and I've read the documentation but it is limited in it's examples imo.

 

If I have 3 VLANS (7,8,9) and VLAN 1 I assume you would go about configuring this in CLI like this? =>
VLAN 8 being a voice vlan, i've applied the configuration from the manual but haven't had the chance to test it yet.
This is what I've got so far:
interface gigabitEthernet 1/0/2
switchport mode general
switchport general allowed vlan 7,8,9 tagged
speed 1000
no shutdown
interface range gigabitEthernet 1/0/7-11
switchport voice vlan mode manual
switchport voice vlan security
switchport general allowed vlan 8 untagged
switchport PVID 8
no shutdown
interface range gigabitEthernet 1/0/15-20
switchport mode general
switchport general allowed vlan 9 untagged
switchport PVID 9
speed 1000
no shutdown

 

With port 2 being the trunk port, now what confuses me is how do I apply the PVID to port 2 as there are multiple VLAN's present.
Is this anywhere near correct?

Thanks in advance

 

"no switchport general vlan allowed 1" is used for remove the port from VLAN 1. If you don't want the port belong to VLAN 1, you can use this command.

About the trunk port, please make sure that the device connected to trunk port support VLAN tag as well. You port 2 is general port and tagged, the data from VLAN 7,8,9 is tagged, I think you don't need to change the PVID for port 2. PVID is used for untagged data, when switch receive the untagged data, the data will belong the VLAN which PVID is. Switch port can only has one PVID.

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#5
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Re:Re:Re:Mode trunk
2019-05-20 09:50:34

zerat wrote

This new system has me very confused...

So on every dedicated VLAN port you need to do "no switchport general vlan allowed 1"?

I'm also confused about the use of PVID, is it obligatory to configure or not?
I've been wanting to apply VLAN's on a T1600G-28TS and I've read the documentation but it is limited in it's examples imo.

 

If I have 3 VLANS (7,8,9) and VLAN 1 I assume you would go about configuring this in CLI like this? =>
VLAN 8 being a voice vlan, i've applied the configuration from the manual but haven't had the chance to test it yet.
This is what I've got so far:
interface gigabitEthernet 1/0/2
switchport mode general
switchport general allowed vlan 7,8,9 tagged
speed 1000
no shutdown
interface range gigabitEthernet 1/0/7-11
switchport voice vlan mode manual
switchport voice vlan security
switchport general allowed vlan 8 untagged
switchport PVID 8
no shutdown
interface range gigabitEthernet 1/0/15-20
switchport mode general
switchport general allowed vlan 9 untagged
switchport PVID 9
speed 1000
no shutdown

 

With port 2 being the trunk port, now what confuses me is how do I apply the PVID to port 2 as there are multiple VLAN's present.
Is this anywhere near correct?

Thanks in advance

 

If you are familiar with cisco (which is obv because of 'no shutdown' :)), PVID is the same as native vlan. All untagged data will go to this VLAN.

If you need typical 'access' port, then delete vlan 1 from the port (no switchport general allowed vlan 1), otherwise your port will receive VLAN 1 traffic, but you do not want it. PVID is OK in your examples.  For some vendors, like D-Link, which also use some kind of only 'general' ports, it is typical to have 'enable pvid auto_assign' command by default, so you do not need to configure PVID manually.

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#6
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Re:Re:Re:Mode trunk
2020-08-16 15:10:22

Hi @Mitya 

 

Im Having same issues with T2600G 28mps v4

 

Im so confused of how this untaged -Taged works in this new switches. I ve recently bought 7 and i have 2 mores v2 and one T1600G V1...  A Chaos Mix. 

 

My doubt is

 

Im using a Cisco Rv345 as router, 1 of the T2600G 28mps v4 as general switch to distribute to the others 9 switches.

 

From router to general Switch im using VLAN140 Untagged  and 101,110,120,130 as Tagged in boths devices. PVID140    asuming that this config is the same as  TRUNK

 

From General Switch To the others Switches  im using VLAN140 Untagged  and 101,110,120,130 as Tagged. in every port they are connected  PVID140, 

 

Here is my question, When i plug a PC, IP Camera with stastic ip, in a port Tagged with a VLAN (supposed 101,PVID101, "cameras vlan") Ive only can ping that device if i untag vlan101 in that port. If not host is inaccesible.

 

I dont understand how Tagged Workds as ACCESS; and UNTAGGED works as GENERAL.

In cisco Tagged is ACCESS and Untagged is TRUNK

 

Should end user devices be connected always in a untagged port of the T2600G 28mps v4? or im messing this in some point?

 

Im so confused 

 

 

Thanks 

 

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#7
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Re:Re:Re:Mode trunk
2020-08-17 06:01:53 - last edited 2020-08-17 07:41:17

 

meckhardt wrote

I dont understand how Tagged Workds as ACCESS; and UNTAGGED works as GENERAL.

In cisco Tagged is ACCESS and Untagged is TRUNK

 

Definitely not! Even for Cisco switches the same is true as for TP-Link switches:
 

  • An Ethernet port can be either an access port or a trunk port.
     
  • An access port is a port which is member of exactly one VLAN. Since its purpose is to connect VLAN-unaware devices, it almost always is an untagged member of this single VLAN. From the view of the connected device there is no VLAN. The VLAN is said to be »terminated« for egress traffic in the switch and the switch »starts« this VLAN for ingress traffic by assigning the VLAN ID according to the Port VLAN ID (PVID) setting.
     
  • A trunk port is a port which is member of several VLANs. Its purpose is to carry traffic for different VLANs over the same physical cable. Since a trunk is used to connect VLAN-aware devices, the port is almost always a tagged member of all VLANs it carries traffic for. From the view of a connected device the VLAN »starts« in the device itself and is »terminated« in this device (or – if a switch – in another device to which it forwards the trunk).

 

There are no different types of trunks. A GENERAL port was a special setting for a trunk in old switches, but it was way to unflexible. Nevertheless, a GENERAL port is a trunk, too. It just behaves differently from a (former) TRUNK port on egress of tagged frames.

 

Usually, a trunk in modern networks does not handle untagged frames. The ability of a trunk to handle untagged traffic (by adding a VLAN ID to untagged frames on ingress according to the PVID and by removing this VLAN ID from frames on egress if it matches the PVID) has been introduced to help migrating an existing non-VLAN network with legacy devices to a VLAN network.

 

If your whole network can handle VLANs, there is no need to use untagged frames at all on trunks. In fact, there are no untagged frames inside a VLAN network. All frames always get assigned to a VLAN, at least inside the switch. A managed switch does not forward untagged frames internally, all frames are always tagged internally even if they had been received untagged and will be emitted untagged by the switch.

 

Setting up VLANs is so easy if you keep some basic rules of thumb in mind:
 

  • Design your networks as if they were separate networks. E.g. for five networks draw a picture (in mind) of five routers, five switch layers, five different client device layers and plenty of cables.
     
  • Now check which device is VLAN-aware:
    • If the router is VLAN-aware, you can use one router for all five networks.
    • If the switch layer (one or more switches) is VLAN-aware, you can use one switch layer for all five networks.
    • If the connected device is VLAN-aware, e.g. a wireless access point, a server / NAS, you can connect this device to all five networks.
    • If a connected device is not VLAN-aware, e.g. a laptop, PC or a camera, your VLAN must be terminated in the switch (or AP) this device is connected to and the device will reside in only one of the five networks.
       
  • Now connect all VLAN-aware devices over trunks to save cables.
  • Then connect all non-VLAN-aware devices to an access port of a switch (or to a SSID of an access point).

 

For example, your router knows five different networks assigned to VLANs 101, 110, 120, 130 and 140. I would start those VLANs on the router, that means the router sets the VLAN tag and the router's port which is connected to the switch therefore is a trunk port. In this case, the switch's port must be a trunk, too. So you assign the router's and the switch's port a tagged membership of all five VLANs.

 

The switch carries traffic of all five networks to another switch over a trunk, too. The other switch also uses a trunk port which is a tagged member of all five VLANs. The PVID does not matter, except if you expect untagged frames appearing on a trunk. But where should untagged frames come from on a trunk? There are none as long as you don't use exotic protocols like those used on some legacy HP servers which did mix untagged and tagged frames on its trunk ports. However, for such weird protocols a trunk can still carry untagged frames if necessary.

 

Of course, if you want to complicate things, you can mix untagged traffic (VLAN 140) and tagged traffic (remaining VLANs) on a trunk. You can also shoot yourself in the foot with a gun, nobody will keep you away from doing so. :-)

 

If you want, you can call such a VLAN 140 an »untagged VLAN« or a »Default VLAN« or a »Native VLAN« or a »System VLAN«, but it isn't untagged inside the switch. It gets tagged with VLAN ID 140, else it would be no VLAN. And managed switches always know only VLANs.

 

Let's assume your wired device is an access point which offers three SSIDs for three of your five networks. The switch port to which the AP is connected to and the port of the AP are trunk ports and as such they must be tagged members of those three VLANs. The VLAN is terminated in the SSID (to be precise: in the virtual interface assigned to this SSID). A client device connecting to one of the three SSIDs connects to one of those three networks provided by the AP, it does not need to know anything about VLANs, it just resides in a single network. Note that the AP itself can also use VLAN-tagged frames (»Management VLAN«) or use untagged frames for management access.

 

A non-VLAN-aware wired laptop or a non-VLAN-aware wired camera will be connected to the switch over an access port. The goal of an access port is to start and to terminate the VLAN in the switch, so the device sees itself as connected to only one (supposedly) non-VLAN network. You assign this switch port an untagged membership of only one VLAN and set the Port VLAN ID (PVID) to this VLAN ID. Frames on ingress now get tagged by the switch (due to the PVID setting) and frames on egress will have the VLAN tag removed by the switch (b/c of untagged membership of the port in this VLAN).

 

Now you might wonder what's the difference of an ancient TRUNK port switch setting vs. a GENERAL port setting.

 

Assume switch #1 adds VLAN tag 140 to untagged frames arriving from the router since you emit untagged frames on the router and have set the switch's PVID to 140 to start VLAN 140 on the switch.

 

Next, assume switch #1 is connected to switch #2 over a trunk. Switch #1 needs to decide how to egress frames in VLAN 140 to switch #2.

 

Should the switch remove the VLAN tag or should it keep the tag? The ancient answer to this question was a subtype for the trunk, namely a GENERAL port:
 

  • A GENERAL port will force the switch to keep the VLAN tag on egress.
  • A TRUNK port will remove the VLAN tag for VLAN 140 on egress since its PVID is 140.
    That's because the PVID rules the switch's behavior on egress to a TRUNK port.

 

This is old style and too unflexible.

 

With the untagged/tagged flag of a switch port you have much finer control of the switch's behavior:
 

  • If the port is an untagged member of VLAN X, the switch removes the tag on egress for all frames with VLAN tag X.
  • If the port is a tagged member of VLAN X, the switch will keep the tag on egress for all frames with VLAN tag X.
  • The PVID no longer determines whether a tag is removed on egress. It still is used to assign untagged frames a VLAN tag on ingress.

 

Nowadays, TP-Link switches use trunk ports which behave like former GENERAL ports used in TP-Link firmwares two generations back (keep tag on egress, that's tagged behavior unless explicitly told to egress untagged frames). The old switches are EoL meanwhile.
 
Don't be confused, there are no GENERAL ports anymore, albeit you still find this ancient port type in the CLI commands. It will force admins who were used to this old notation to use (former) GENERAL ports for trunks. But those ports are trunk ports as per definition.

 

Home work left to the reader:

  1. Can an access port be a member of two VLANs if untagged? And if so, for what purpose?
  2. Can a trunk port be a member of only one VLAN if tagged? If so, does this make any sense?
  3. Can a VLAN be terminated inside a client device such as a laptop or PC? If so, for what purpose?
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#8
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Re:Re:Re:Mode trunk
2021-05-23 20:39:03
I want to express my gratitude, your post is gold. Thank you
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#9
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Re:Re:Re:Mode trunk
2021-05-29 00:39:08

@Luchito TP has a way of complicating things haha

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#10
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Re:Mode trunk
2021-05-29 05:36:21

@glecomte 

I have a 7pcs TP-Link 2600G-52TS firmware:v4

 

And a pfSense with LAN interface IP addr network: 10.10.6.x with

VLAN30 IP addr network: 192.168.30.x

VLAN 40 IP addr network: 192.168.40.x

 

And Unifi UAP-AP with VLAN30 and VLAN40

 

my problem is that how to set up the switch interfaces.

In TP-Link interface gi 1/0/5 where I will plug the Access Point, interface gi 1/0/1 routed port IP adrr of 10.10.6.195 where my Uplink to pfsense.

How can I set the VLANs?

Will the 10.10.6.x network coming from TP-Link SW routed port be untagged?

And as for Access Point the interface gi 1/0/5 should be set as trunk port right? Because of 2 VLANs?

The TP-Link VLAN1 network would be: 172.16.5.0 network

 

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#11
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Replies: 10

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