Shared ports on a VLAN

[dachilli]

I'm looking for some help with my 2928 SFP Plus switch. I'd like to be able to create ports that can be see on multiple VLANs. Here is how I'd like to have it set up:

Switch is 192.168.0.100 / 24

VLAN 2  ports 1-4

VLAN 3 ports 5-8

VLAN 4 ports 9-12

Ports 20 and 21 to be see by all VLANS ( This is where my router/ firewall and back up server will reside)

Can this be accomplished and if so how?

[Fred_Mancen_1]

Set the ports you want to pass all VLAN as a hybrid port, and then assign it to the tagged VLANs you need to pass, the native VLAN will remain untagged.

HTH

[dachilli]

So,  would I set up my VLAN ports as tagged or untagged ?

For example,

VLAN 2 ports 1-4 tagged or untagged ?

VLAN 3 ports 5-8 tagged or untagged ?

ports 20,21 tagged (Hybrid) members of VLANs 2,3,x ?

Thanks a bunch for your help.

[Fred_Mancen_1]

The ports that you will use with just one VLAN assigned (access ports) you have to setup the VLANs as untagged. The default VLAN in every port is the VLAN 1, which is untagged. Since you change the VLAN to another one you have to define it as untagged in order to eliminate the VLAN 1 from the port configuration.

In the hybrid ports you will setup the native VLAN (PVID) as untagged, and the others as tagged. Example: if your firewall uses the VLAN 2 as the native VLAN (with an IP address assigned to this VLAN), you will setup the VLAN 2 as untagged, and the VLAN 3 as tagged.

If your router supports 802.1Q protocol, setup the switch port as a trunk port, and configure the trunk to permit the trafiic of the VLANs you want to pass through the connection. To deny the traffic coming from VLAN 1 (default VLAN) in the trunk, you can remove the VLAN 1 from the permission. If you prefer to use the hybrid mode, setup the portas the same way used to the firewall connection.

HTH

[dachilli]

Here is my current config from what I understand you saying:

Port                                              untgd      tagged           port type                       PVID

GE1/0/1	2		Access	2
GE1/0/3	2		Access	2
GE1/0/4	2		Access	2
GE1/0/2	2		Access	2
GE1/0/21	5	2-3	Hybrid	5
GE1/0/22	5	2-3	Hybrid	5
GE1/0/23	5	2-3	Hybrid	5
GE1/0/24	5	2-3	Hybrid	5

Right now my PC is plugged into port 3 with the PC IP address of 10.0.50.234 /24

I have a NAS device plugged into port 23. NAS IP 10.0.50.78 /24

When I attemp to ping the NAS from the PC I get destination host unreachable. Is there something I'm missing ? Maybe the NIC set up on the PC or NAS ?

Thanks!

[Fred_Mancen_1]

Did you configured the correct default gateway at the PC? In order to reach hosts from different network segments you need to have a layer 3 device with some routing protocol or static routes configured. If the PC already has a default gateway in the IP settings maybe there is some routing parameter missing on the L3 device (router or firewall with L2/L3 capabilities).

HTH

[dachilli]

They are all using the same 10.0.50.253 gateway address. If all of the devices are on the same IP network 10.0.50.x /24 does the gateway matter? I apologize, I am quite new to the whole VLAN thing so if my questions are somewhat basic, this is the reason.

[Fred_Mancen_1]

Ok. VLANs are created at the Layer 2, and to communicate among the VLANs you have to create the Layer 3 interfaces (VLAN interfaces) and associate subnets to these interfaces. The subnets have different subnets, this is mandatory. In order to route among these VLANs, you need to have a multilayer switch or a router with 802.1Q support, if not you cannot route and communicate among the VLANs.

[dachilli]

Hmmmm.

If I have to route all the traffic with a L3 device, what is the point of having a L2 switch? I could buy just a bunch of 5 port GB switches, couldn't I ? I guess I'm just not understanding the benift of VLANing then.