HP Cisco Catalyst Blade Switch 3020 Release Note page 10

Limitations and Restrictions
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Trunking
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VLAN
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Release Notes for the Cisco Catalyst Blade Switch 3020 for HP, Cisco IOS Release 15.0(2)SE and Later
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During periods of very high traffic when two RSPAN source sessions are configured, the VLAN ID
of packets in one RSPAN session might overwrite the VLAN ID of the other RSPAN session. If this
occurs, packets intended for one RSPAN VLAN are incorrectly sent to the other RSPAN VLAN.
This problem does not affect RSPAN destination sessions.
The workaround is to configure only one RSPAN source session. This is a hardware limitation.
(CSCea72326)
Cisco Discovery Protocol (CDP), VLAN Trunking Protocol (VTP), and Port Aggregation Protocol
(PAgP) packets received from a SPAN source are not sent to the destination interfaces of a local
SPAN session.
The workaround is to use the monitor session session_number destination {interface interface-id
encapsulation replicate} global configuration command for local SPAN. (CSCed24036)
The switch treats frames received with mixed encapsulation (IEEE 802.1Q and Inter-Switch Link
[ISL]) as frames with FCS errors, increments the error counters, and the port LED blinks amber.
This happens when an ISL-unaware device receives an ISL-encapsulated packet and forwards the
frame to an IEEE 802.1Q trunk interface.
There is no workaround. (CSCdz33708)
IP traffic with IP options set is sometimes leaked on a trunk port. For example, a trunk port is a
member of an IP multicast group in VLAN X but is not a member in VLAN Y. If VLAN Y is the
output interface for the multicast route entry assigned to the multicast group and an interface in
VLAN Y belongs to the same multicast group, the IP-option traffic received on an input VLAN
interface other than one in VLAN Y is sent on the trunk port in VLAN Y because the trunk port is
forwarding in VLAN Y, even though the port has no group membership in VLAN Y.
There is no workaround. (CSCdz42909).
For trunk ports or access ports configured with IEEE 802.1Q tagging, inconsistent statistics might
appear in the show interfaces counters privileged EXEC command output. Valid IEEE 802.1Q
frames of 64 to 66 bytes are correctly forwarded even though the port LED blinks amber, and the
frames are not counted on the interface statistics.
There is no workaround. (CSCec35100).
If the number of VLANs times the number of trunk ports exceeds the recommended limit of 13,000,
the switch can fail.
The workaround is to reduce the number of VLANs or trunks. (CSCeb31087)
When dynamic ARP inspection is configured on a VLAN, and the ARP traffic on a port in the VLAN
is within the configured rate limit, the port might go into an error-disabled state.
The workaround is to configure the burst interval to more than 1 second. (CSCse06827)
When many VLANs are configured on the switch, high CPU utilization occurs when many links are
flapping at the same time.
The workaround is to remove unnecessary VLANs to reduce CPU utilization when many links are
flapping. (CSCtl04815)
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