Cisco Gigabit Ethernet Switch Module for HP BladeSystem p-class Release Notes, Cisco IOS Release 12.2(50)SE and later

Cisco Gigabit Ethernet Switch Module for HP BladeSystem p-Class Release Notes, Cisco IOS Release 12.2(50)SE and later

515765-002

Limitations and Restrictions

• When auto-QoS is enabled on the switch, priority queuing is not enabled. Instead, the switch uses

shaped round robin (SRR) as the queuing mechanism. The auto-QoS feature is designed on each

platform based on the feature set and hardware limitations, and the queuing mechanism supported

on each platform might be different. There is no workaround. (CSCee22591)

SPAN and RSPAN

These are the SPAN and Remote SPAN (RSPAN) limitations.

• An egress SPAN copy of routed unicast traffic might show an incorrect destination MAC address on

both local and remote SPAN sessions. This limitation does not apply to bridged packets. The

workaround for local SPAN is to use the replicate option. For a remote SPAN session, there is no

workaround.

This is a hardware limitation: (CSCdy72835)

• Egress SPAN routed packets (both unicast and multicast) show the incorrect source MAC address.

For remote SPAN packets, the source MAC address should be the MAC address of the egress VLAN,

but instead the packet shows the MAC address of the RSPAN VLAN. For local SPAN packets with

native encapsulation on the destination port, the packet shows the MAC address of VLAN 1. This

problem does not appear with local SPAN when the encapsulation replicate option is used. This

limitation does not apply to bridged packets. The workaround is to use the encapsulate replicate

keywords in the monitor session global configuration command. Otherwise, there is no

workaround.

This is a hardware limitation: (CSCdy81521)

• 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: (CSCed24036)

• 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.

Trunking

These are the trunking limitations:

• The switch treats frames received with mixed encapsulation (802.1Q and Inter-Switch Link [ISL])

as frames with FCS errors, increments the error counters, and causes the LED to blink amber. This

happens when an ISL-unaware device receives an ISL-encapsulated packet and forwards the frame

to an 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