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Cisco IP Phone 7985 invalid source multicast

We have couple of Cisco IP Phone 7985 deployed. We have noticed the following logs:

%SYS-4-P2_WARN: 1/Invalid traffic from multicast source address 35:4f:81:00:00:63 on port 6/29

Understand that source ip address should never be multicast. We have seem the above log appearing in switchport when the Cisco IP Phone 7985 is attached.

Also, the usual multicast should start with 01:00:5e and our case it start with

35:4f:81.

Can anyone advise? Is there a concern on this.

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Re: Cisco IP Phone 7985 invalid source multicast

<http://www.cisco.com/warp/public/473/176.html#subtopic1m>

%SYS-4-P2_WARN: 1/Invalid traffic from multicast source address

Problem

The switch generates Invalid traffic from multicast source address messages.

Description

This example shows the syslog output that you see when this error occurs:

SYS-4-P2_WARN: 1/Invalid traffic from multicast source address

81:00:01:00:00:00 on port 2/1

%SYS-4-P2_WARN: 1/Invalid traffic from multicast source address

81:00:01:01:00:00 on port 2/1

The switch generates the Invalid traffic from multicast source address syslog message when the switch receives packets with a multicast MAC address as the source MAC. The use of a broadcast or multicast MAC address as the source MAC for a frame is not standards-compliant behavior. However, the switch still forwards traffic that is sourced from a multicast MAC address.

The syslog message indicates the multicast MAC address in the source MAC field of the frame, as well as the port on which the traffic was received.

The workaround is to try to identify the end station that generates frames with a multicast source MAC address. Typically, one of these devices transmits such frames:

* A traffic generator, such as SmartBits

* Third-party devices that share a multicast MAC address, such as load-balancing firewall or server products

hth,

Ajaz

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