can't get 802.1Q to work

RouterOS General
1

Hi Guys,

i have a mikrotik 450G (and tried 750) with VLAN 1 on port 2, and an IP allocated to that vlan1.

then i connect a switch (namely ‘planet’), i setup that switch to use 802.1Q with vlan 1 on the port that the Mikrotik connects to.

but when i use the mikrotik and ping the ip of the switch strangly:

a) i cannot ping the switch unless i put the switch into port based vlan1.
b) i cannot sniff any packets going out on vlan 1 yet i can see traffic on that vlan

im thinking mikrotik isnt doing true 802.1 Q?

2

Or your Planet switch does not really support VLAN.

According to PLANET Technology Corporation, some switches has limitations when operating in multilayer mode.

3

ive replaced the planet with a cisco 3500xl and the same thing happens… ive also replaced the mikrotik connection to the planet with a pc and it works fine…


have i missed any steps to configuring 802.1Q on the mikrotik?

4

what’s your ROS config?..

5

the router os config is as simple as what i mentioned in the first line above.

  1. attatch vlan1 to eth2
  2. give vlan1 and ip address
6

a) dot1q is working fine for me between an RB1000 and a 3560G. Post the output of “/int eth pri det”, “/int vl pri det”, “/ip add pri det” from the RouterOS device, and “sh vlan” and “sh run int fa0/x” (substitute for uplink port) on the Cisco side.

b) Wild guess: vlan 1 is special on Cisco (it’s the default native vlan). The native on a port has all dot1 tags stripped when forwarded out the port. Unless you’ve set the native vlan on the port to be something else, you’re sending out a packet without a dot1q tag to a device that expects a dot1q tag to match traffic to its vlan 1 interface. Since there’s no tag, traffic doesn’t go to the vlan interface but to the ethernet interface instead as that receives all non-dot1 traffic. Either use vlan 2, or set the native vlan on the Cisco port to 2 (or something else).

7

i found that the planet wasn’t working with the mikrotik (most likely planet fault) with tagged setting so i set port to untagged and all is well with no vlans for management.