315PN DP double mac address

JOLTRON · Aug 12, 2011

I'm sorry if this has already been talked about. When I did a search I only found information about CP's.

Anyways, I have a 7 315 2PN/DP's. Each of these processors has 2 ports on the front of it for profinet.

From what I gather from the manual and siemens site, each processor has 3 mac addresses. The mac address of the device(mac) the mac address for port 1(mac +1) and the mac address for port 2(mac+2).

Now the mac addresses printed on the face of each processor is different. Also from the command prompt if I ping any of the processors and the do an "arp -a" I get a unique mac address for each device.

The problem, when all of the processors are connected to a managed cisco switch it freaks out for having a duplicate mac addresses on differnet ports(Flapping), and also for having multiple macs a a single port.

After talking with IT and doing reading it looks like it is do to LLDP (Link Layer Discovery Protocol), which I see on older CP's it was an option that could be disabled.

The closest thing I see on the processor is an option that can be enabled on either port for "End of topology discorver"

Has anyone seen this before?

JOLTRON · Aug 29, 2011

Just giving this thread a bump to see if I can catch anyone's attention this time around.

TurpoUrpo · Aug 29, 2011

JOLTRON said:
..

The problem, when all of the processors are connected to a managed cisco switch it freaks out for having a duplicate mac addresses on differnet ports(Flapping), and also for having multiple macs a a single port.
...

In what way they are networked? Remember those ports are switched ports, its two ports out + one port to cpu. So it does have multiple macs in one port. Duplicate mac's there would be if also cpus are connected together.

JesperMP · Aug 29, 2011

Any difference if you enable the "End of topology discover" ?

JOLTRON · Aug 29, 2011

TurpoUrpo said:
In what way they are networked? Remember those ports are switched ports, its two ports out + one port to cpu. So it does have multiple macs in one port. Duplicate mac's there would be if also cpus are connected together.

I'm not sure what you mean.
I know that each PLC has a unique MAC address, and Port 1 is the MAC address +1 and Port 2 is the MAC address +2.
Each PLC has a Ethernet cable running from Port 1 to our Cisco switch.

JesperMP said:
Any difference if you enable the "End of topology discover" ?

I have not tried it yet since I am not on site yet, I was curious if anyone has had to do this before.

TurpoUrpo · Aug 29, 2011

JOLTRON said:
I'm not sure what you mean.
I know that each PLC has a unique MAC address, and Port 1 is the MAC address +1 and Port 2 is the MAC address +2.
Each PLC has a Ethernet cable running from Port 1 to our Cisco switch.

This is only cpu:

Code:

PORT1--SWITCH--PORT2
          |
         PLC

So there is multiple macs behind one port of Cisco switch.

Is this how you network is connected:

Code:

PLC1_SWITCH_PORT1---CISCO---PLC2_SWITCH_PORT1

There must not be any other link from PLC1 to PLC2 than trough CISCO, otherwise it will find same PLC trough both ports.

JOLTRON · Aug 29, 2011

TurpoUrpo · Aug 29, 2011

JOLTRON said:
Layout of Cisco Switch.

---------
|Cisco |
|Switch |
| |
|Port 1 |-----PLC 1 port 1
|Port 2 |-----PLC 2 port 1
|Port 3 |-----PLC 3 port 1
|Port 4 |-----PLC 4 port 1
|Port 5 |-----PLC 5 port 1
|Port 6 |-----PLC 6 port 1
|Port 7 |-----PLC 7 port 1
|Port 8 |-----HMI 1
|Port 9 |-----HMI 2
|Port 10|-----HMI 3
|Port 11|-----HMI 4
---------

If there really is nothing else (no cables in port2's of plc's), then duplicate mac's alert seems very odd.

315PN DP double mac address

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