SONET and MAC address

Thu Dec 9 07:54:48 UTC 2010

Fuji 4500 gear, depending on the card, software release, and configuration,
can support or not support tagged traffic, which might also be
distinguishing aspect that your vendor may not be aware of.

Let me know if you need a bit more details, and I can ask our consultant who
works with these boxes on a regular basis.

Frank

-----Original Message-----
From: Jay Nakamura [mailto:zeusdadog at gmail.com] 
Sent: Wednesday, December 08, 2010 2:33 PM
To: NANOG
Subject: SONET and MAC address

We have a Gigabit Ethernet transport between cities by a vendor.  We
found that when there are identical MAC address that are on different
VLANs on different side of the circuit, one of the VLAN looses
packets.  This situation came up because two different networks that
travel over the Ethernet were using HSRP with the same virtual MAC
address.

The vendor says both sides are directly connected to Fujitsu SONET
gear and the equipment doesn't even look at the MAC address so it's
not their circuit.  All I know is, I can't recreate the problem if
this circuit is not in the path.

I haven't worked with Fujitsu SONET gear so I don't know if their
claim is true or not.  I vaguely remember someone talking about some
equipment actually having a builtin switch on the SONET port and that
was messing up the forwarding.

Also, on one side of the circuit, there is a copper to fiber media
converter.  I am going to find out what model this is and see if that
could be the cause.

Anyone have any thoughts on what I should look into or have the vendor
look into?  Anyone run into this situation?

Thanks!