Protocol Migration check is inconsistent with two switch topology.

[Rajani]

Hi Vitalli,

While testing, I had observed the below issue.

With two switch topology, SW1(RSTP mode) and SW2(STP mode), port protocol migration check is inconsistent on RSTP enabled switch.

Steps to reproduce the issue:
1. Connect two switches (SW1(port1) --> SW2(port1)), where SW1 is the Root Bridge.
2. After STP calculation, we can observe that port1 of SW1 as Designated port and port1 of SW2 as Root Port. And Both switches communicates through STP Config BPDU's.
3. After sometme if we do portmcheck on port1 of SW1, I could see only RSTP BPDUs will be communicated on SW1, Instead of STP config BPDU's.

Kindly let us know your inputs.

Regards,
Rajani

[Rajani]

(For the reference) Attachement is the packets captured at SW1 (RSTP enabled switch), after the port protocol Migrtaion check enabled on it.

[satyanarayana]

Hi Vitalli,

Code change has been done in mstp.c file in MSTP_IN_port_mcheck( ) function,

/ 12.8.2.5 Force BPDU Migration Check /
int MSTP_IN_port_mcheck(port_t prt)
{
bridge_t br = prt->bridge;
per_tree_port_t *cist = GET_CIST_PTP_FROM_PORT(prt); //changes

if(rstpVersion(br) && prt->portEnabled && br->bridgeEnabled)
{
    prt->mcheck = true;
 cist->proposing = true; //Changes
    br_state_machines_run(br);
}

return 0;

}

We have done basic testing successfully, let us know your opinion on the same.

[Satish Ashok]

Hi Rajani/Satyanarayan,
I was able to reproduce this issue and I tried out the fix you suggested, things look good. I shall be running IXIA ANVL tests with this change to verify no other functionality is broken and I shall then check-in this change.

Thanks,
Satish

[Satish Ashok]

Hi Rajani/Satyanarayan,
I have committed the change with revision 61, thanks for reporting and fixing the issue..

Thanks,
Satish