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Re: XRN Stack 3Com 5500GEI - Routing Problems

Occasional Visitor

XRN Stack 3Com 5500GEI - Routing Problems

Hi there,

we got a problem with our main Network Stacked Core that consists of two 3Com 5500GEI in a Fabric.

Our topology is something like the attached image.

We currently have two Main LAN Networks in 2 buildings, geografically distant and are interconnected by a Fibre Link at Layer 3. The Network Core of building A, has about 50 vlan networks in its routing table, and about the same at other site.

The absolutely absurd problem we have is, in Building A. Both 5500GEI are properly cross connected, Cascade interfaces are set to fabric ports, sysname and global configurations are identical, Comware is exact the same. But Unit 1 reach about 2/3rds of the entire networks in building B.

This means that every single link directly connected to Unit 2 (currently the master) can reach every corner of the entire network, but those links directly connected to Unit 1 (In the very same stack, with all above properties)  do not reach all of them  (even with the very same port config, With NO ACLs of any kind) and reach aleatory parts of the network, this means by a moment reach network "a", "b" ,"c" but then "a" is unreachable and now it reachs b, c and d networks.

Do somebody know what could be happening ?


  • display topology information and display topology databases show a Ring topology properly establisehd with Normal Status.
  • We can create Distributed Link agregations to both units, but they are just not L3 forwarded propperly.
  • Unit 1 can reach every network that is DIRECT in its routing table, but no the specified by its gateway the linux Firewall

We have triple cheked every configuration, could this be a Hardware related issue ? some kind of corrupted routing capabilities in unit 1 ?

We have scheduled a maintance to rebuild the stack, but i think that will not resolve this.

Any help is extremely appreciated.


Occasional Visitor

Re: XRN Stack 3Com 5500GEI - Routing Problems

We were able to solve this issue, and  i will paste the solution in case someone has this problem.

We did a  dir /fabric  and verify the very same files were in both units. (There were two *.log files in one unit, wich were deleted.)
We did a  reset ftm statistics, clearing all counters
We turned off the affected unit by pulling the power cord and restarted it, with the planned consequence of make the second unit reboot when the first one got up.

Best regards.