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CISCO SWITCHES FOR SMALL and MEDIUM BUSINESS

Introducing the next generation of Cisco Small and Medium Business Switches. Cisco is refreshing its SMB Switch portfolio. Click here  to learn more.


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Problem with GVRP in combination with Link Aggregation?

Hi,

At our office we use seven Cisco 300 Series Small Business Switches. One main switch in the server room and one in each room. They work great! But I’m having weird behaviors with GVRP in combination with Link Aggregation. LAG's seem to get mixed up. If it is not a normal behavior I really got the feeling there might be a bug in the firmware. It is hard to explain, but I will do my best to describe our scenario.

Switch (main server room):

  • Cisco SG 300-28 (PID:SRW2024-K9)-VSD <<< known as swtich 1 (configured with LAG 3 to 8)

Switches (one in each room):

  • Cisco SG 300-10P (PID:SRW2008P-K9)-VSD <<< known as swtich 3 (configured with LAG 1)
  • Cisco SG 300-10 (PID:SRW2008-K9)-VSD <<< known as swtich 4 (configured with LAG 1)
  • Cisco SG 300-10 (PID:SRW2008-K9)-VSD <<< known as swtich 5 (configured with LAG 1)
  • Cisco SG 300-10 (PID:SRW2008-K9)-VSD <<< known as swtich 6 (configured with LAG 1)
  • Cisco SG 300-10 (PID:SRW2008-K9)-VSD <<< known as swtich 7 (configured with LAG 1)
  • Cisco SG 300-10 (PID:SRW2008-K9)-VSD <<< known as swtich 8 (configured with LAG 1)

All these switches use firmware v1.1.1.8. Each switch in each room is connected to the main switch by Link Aggregation (2xGE). The main switch is configured in Layer 3 mode and all the others in Layer 2 mode. We have a lot of VLAN’s configured which are actually not relevant for this post.

  • The main switch has LAG 3, 4, 5, 6, 7 and 8 configured.
  • The other switches only have LAG 1 configured (all of them connecting to the main switch).

The LAG ID’s somewhat reflect the switch hostname/number (e.g. LAG 3 is connected to switch 3). The Link Aggregations seem to work properly. The network is fully routable. A DHCP Server is available. Each VLAN uses DHCP relaying. If we statically assign a VLAN to a port and the LAG, that just works fine. Great switches.

But… here it comes; when we enable GVRP all LAG's seem te get mixed up. The following issue occurs which is quit confusing.

  • When I change a VLAN setting on let’s say LAG 3. Nothing changes on switch 3. But it changes on switch 4 instead.
  • When I change a VLAN setting on let’s say LAG 4. Nothing changes on switch 4. But it changes on switch 3 instead.
  • When I change a VLAN setting on let’s say LAG 5. Nothing changes on switch 5. But it changes on switch 7 instead.
  • When I change a VLAN setting on let’s say LAG 6. Changes are seen on switch 6, as it should!
  • When I change a VLAN setting on let’s say LAG 7. Nothing changes on switch 7. But it changes on switch 8 instead.
  • When I change a VLAN setting on let’s say LAG 8. Nothing changes on switch 8. But it changes on switch 5 instead.

It seems as if the GVRP settings are not forwarded the right LAG.

Is this a normal behavior?

Am I doing something wrong?

Do the LAG ID numbers need to match on each switch?

Another issues happend. Although they are mixed up GVRP works. But once I enabled Auto Voice VLAN GVRP stopped working. Is there a reason for it? I really hope someboady can help me. At this moment I have disabled GVRP. But it a hessle to configure the VLAN's between te LAG, as some switchs need to be modified quit often and we have a lot of VLAN's.

Everyone's tags (5)
2 REPLIES 2

Problem with GVRP in combination with Link Aggregation?

Nobody?

I question myself. Might this be a bug? Are there things I need to be aware of when I configure LAGs?

Frequent Contributor

Problem with GVRP in combination with Link Aggregation?

Boudewijn,

Please call Cisco Small Business Support Center for assistance with your issues @ 1-866-606-1866 and open a support case. Would like to take a look at your complete network topology and see the exact behavior explained in this community post. As I have set up 4 SG300-10 switches and did not have the behavior you described.

Thanks,

Jasbryan