Thanks for the response. The layer 3 traffic is unicast. I have poked
around further and found the counters from the command "show platform
software drop-port" for "InpL2AclDrop" are increasing with my missing
packets.
4900M#show platform software drop-port | in Drop Event
Reason|InpL2AclDrop|Time
Time source is NTP, 16:35:59.675 NZST Sun Jun 29 2014
Drop Event Reason Packets Dropped
InpL2AclDrop 1433452028
4900M#show platform software drop-port | in Drop Event
Reason|InpL2AclDrop|Time
Time source is NTP, 16:36:02.843 NZST Sun Jun 29 2014
Drop Event Reason Packets Dropped
InpL2AclDrop 1433496091
4900M#show platform software drop-port | in Drop Event
Reason|InpL2AclDrop|Time
Time source is NTP, 16:36:07.020 NZST Sun Jun 29 2014
Drop Event Reason Packets Dropped
InpL2AclDrop 1433539406
So far I haven't been able to find any additional details about this. I
am guessing it is some kind of inbuilt L2 ACL.
Cheers
Ivan
On 29/Jun/2014 2:33 p.m., Justin Krejci wrote:
Is the layer 3 traffic multicast? Your indication of HA makes me suspect
it is and perhaps you have a multicast snooping/filtering on the Cisco
or some other related limiter setting.
Just a total guess without any configs or other pertinent data.
-----Original Message-----
*From:* Ivan [[email protected]]
*Received:* Saturday, 28 Jun 2014, 5:10PM
*To:* cisco-nsp [[email protected]]
*Subject:* Re: [c-nsp] Cisco 4900M and Layer2 Broadcasts
Sorry to respond to my own post but I have some further thoughts that
may be useful. The traffic ends up being broadcast at layer 2 (dest MAC
address ff:ff:ff:ff:ff:ff) but the IPv4 payload is generally unicast.
So I am thinking perhaps the 4900M could be "getting upset" with these
packets. Not really expecting the 4900M to look higher than layer 2 of
these packets though as vlan does not have SVI.
Ivan
On 28/Jun/2014 10:17 p.m., Ivan wrote:
I am hoping someone may have come across an issue I am seeing on a Cisco
4900M running 15.1(2)SG3.
I have a device connected to an interface sending traffic from it's own
MAC address to MAC address ff:ff:ff:ff:ff:ff. When the layer 3 protocol
is IPv6 I see this going out other port in the same vlan as the source -
all good. When the layer 3 protocol is IPv4 the frames seem to go into
a black hole - very bad. I have confirmed all this with packet captures.
I have poked around but cam find any indication of the issue. I will be
logging a TAC case in the next day or two for this but would be
interested to hear if anyone else has seen this.
Thanks
Ivan
PS. Not really looking to get into the details of the connected devices
etc - just some HA type traffic using layer 2 over a vlan.
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