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KB80569
SNAP PAC devices receiving long 802.1Q VLAN broadcasts may have communication failures
Revision:  2.0
Published:  5/12/2010
Applies To
SNAP-PAC-S1
SNAP-PAC-S2
SNAP-PAC-R1
SNAP-PAC-R2
SNAP-PAC-S1-W
SNAP-PAC-S2-W
SNAP-PAC-R1-W
SNAP-PAC-R2-W
Versions
In all versions up to and including version:  
R8.5a
Resolution is included beginning in version:  
B8.5b
Problem is fixed in version:  
R8.5c

SYMPTOMS

If an affected SNAP PAC device is connected to an Ethernet segment that carries IEEE 802.1Q VLAN traffic, it may become unresponsive to Ethernet communication.

The IEEE 802.1Q standard increased the maximum Ethernet fram size from 1518 bytes to 1522 bytes to accommodate the VLAN tag. If any frames longer than 1518 bytes are received by an affected SNAP PAC device, memory corruption occurs.

WORKAROUND

Disable 802.1Q VLAN for the 802.1Q compatible switch port to which the SNAP PAC devices are attached. By doing so, the SNAP PAC devices do not receive VLAN tagged messages.

CASE STATUS

Opto 22 has resolved this issue.

Relevant Downloads
No relevant downloads have been specified.
Questions? Contact Opto 22 Product Support.
Phone: 800-835-6786 or 951-695-3080
Email: support@opto22.com

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