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  1. #1
    Junior Member psh is on a distinguished road
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    VLAN configuration problems TL-SG1024DE and two hop TL-SG105E

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    I have an existing VLAN infrastructure in my house that relies on legacy switches from 3Com and Cisco. I was hoping to replace this with a set of TP-LINK switches.

    At the core in the new setup I have one TL-SG1024DE. Connected to that is a mid-hop via a TL-SG105E and onto one "edge" TL-SG105E and one "edge" TL-SG108E. Firmware appears to be current. I am familiar with VLANs including tagged and untagged ports. I use that in my existing configuration. The firewall is connected to the new 1024 via a tagged port and uses vlan interfaces to handle routing in between. The 1024 has a tagged port to reach three VLANs that are present on the 105/108s. The incoming port to the first 105 uses tagging and has all the relevant VLANs defined as tagged to that "uplink". Two ports on the 105 are tagged to forward traffic to the 105/108. The 105/108 have two VLANs. Tagging on their "uplink" and untagged on the other ports. I have made sure to set PVID on all untagged ports to match the untagged VLAN I want on the port.

    I used a CentOS laptop as a test vehicle and connected it into untagged ports that I then pinged from the firewall. I checked the traffic with promiscuous tcmpdump on the firewall, to see what traffic was flowing. Going through the 1024 and onwards to devices attached to next level TP-LINK switches was not working. I could see that arp-who-has requests going out but nothing coming back. I tried a variety of permutations, but no luck.

    The built in tools in the switches are limited so I cannot, for example, see what MACs are picked up where. Is this combination supposed to work? And, if so, what are the constraints?

    Thanks,

  2. #2
    You are confident about VLAN knowledge. I think your configuration if correct.
    Going through the 1024 and onwards to devices attached to next level TP-LINK switches was not working. I could see that arp-who-has requests going out but nothing coming back. I tried a variety of permutations, but no luck.
    Generally if the switch doesn't know the destination MAC of the data, it will broadcast the data. So do you mean that the ARP data form the firewall cannot reach the laptop? It may be related to your VLAN settings.

    As far as I know, we can not see what MACs are picked up on the Switch of TL-SG1024DE/108E/105E.

  3. #3
    What VLAN mode are you using? The switches support MTU VLAN, Port Based VLAN, and 802.1Q VLAN. Though similar in concept, the behavior and management of these is very different.

    Also, are you managing the switches using the built-in web UI or the Easy Smart Configuration utility? Depending upon the utility version, switch hardware versions, firmware versions, not all features and functions of the switches are accessible through the config utility.

    AND to top it off, not all features and functions are the same across all the switches in the Easy Smart family. For example, when using 802.1Q VLAN, the TL-SG108E latest firmware version allows removing VLAN 1 from a port ONLY through the web UI. That function does not exist in the config utility and is not supported at all on the TL-SG1024DE.

    Having said all that, if you are using 802.1Q VLAN and using the config utility, you need to recognize that the options being set on the "802.1Q VLAN" page define "egress rules". That is, which ports will send packets tagged with each VLID.

    The "802.1Q PVID Setting" page defines the per-port "ingress rule". Ingress rules define what VLID will be applied to untagged packets received on the port. You cannot set a port to have no ingress rule which means that every packet "inside" the switch carries a VLID (most of the time it will be VLID 1).

    The thing that confuses most people is that VLID 1 is the de facto "no VLAN" VLAN. with every port set to untag VLID 1 packets on transmit (remember, this can't be changed on the 1024DE) and to tag all untagged packets with VLID 1 on receive (changeable), the switches will function somewhat in factory reset state.

    Hope this helps.


 

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