VLAN communication between 2 SG300-28P using one LAG

[LDEFNEURO]

Hi,

I have 2 SG300-28P without a router used for back-end network usage.

The switches are configured in L2.

I would like to configure on both switches:

• The default VLAN with Id 90
• One VLAN with Id 80 to access the databases
• One VLAN with Id 70 to access the backup server
• One agregate with ports 25/26/27/28
• Ports 1 to 8, 13 to 20 with VLAN 80 (90UP/80T)
• Ports 9 to 12, 21 to 24 with VLAN 70 (70UP)

Computers connecting in VLAN 70 will only talk to VLAN 70.

I would like to use the access mode for ports in VLAN 70.

Computers connecting in VLAN 80 will only talk to VLAN 80.

It seems that the servers on VLAN 80 on switch 1 can communicate with servers on VLAN 80 on switch 2.

My problem is that the servers on VLAN 70 on switch 1 don't access the servers on VLAN 70 on switch 2.

I suppose that this is due to the LAG 25/26/27/28 configured 90UP.

Any idea to resolve this problem?

[Tom Watts]

Hi Luc, the LAG should be configured with all vlans tagged to it, such as 90u, 70t, 80t. This should allow 70 to talk to 70 and 80 to talk to 80 between the switches.

-Tom
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[LDEFNEURO]

Hi,

Thanks for your quick answer.

However, I can not configure VLANs on the ports configured in the LAG. I have an error message each time I tried to do it. I can only have 90u.

[Tom Watts · Accepted solution]

The LAG is like any other link. It is configurable. You should be able to log the cli

config t

int po1

switchport mode trunk

switchport trunk native vlan 90

switchport trunk allowed vlan add 70,80

-Tom
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[LDEFNEURO]

Thanks a lot. You are right.

This configuration can not be performed using the web interface. Only in command line.