Cisco Gigabit Ethernet Switch Module for HP BladeSystem p-Class Release Notes, Cisco IOS Release 12.2(46)SE

501396-001

Limitations and Restrictions

HSRP

When the active switch fails in a switch cluster that uses HSRP redundancy, the new active switch might

not contain a full cluster member list. The workaround is to ensure that the ports on the standby cluster

members are not in the spanning-tree blocking state. To verify that these ports are not in the blocking

state, see the “Configuring STP” chapter in the software configuration guide. (CSCec76893)

When the rate of received DHCP requests exceeds 2,000 packets per minute for a long time, the response

time might be slow when you are using the console. The workaround is to use rate limiting on DHCP

traffic to prevent a denial of service attack from occurring. (CSCeb59166)

IP Telephony

This is the IP telephony limitation:

After you change the access VLAN on a port that has 802.1x enabled, the IP Phone address is

removed. Because learning is restricted on 802.1x capable ports, it takes approximately 30 seconds

before the address is relearned. No workaround is necessary. (CSCea85312)

Multicasting

These are the multicasting limitations:

• If the number of multicast routes and Internet Group Management Protocol (IGMP) groups are more

than the maximum number specified by the show sdm prefer global configuration command, the

traffic received on unknown groups is flooded in the received VLAN even though the show ip igmp

snooping multicast-table privileged EXEC command output shows otherwise. The workaround is

to reduce the number of multicast routes and IGMP snooping groups to less than the maximum

supported value. (CSCdy09008)

• IGMP filtering is applied to packets that are forwarded through hardware. It is not applied to packets

that are forwarded through software. Hence, with multicast routing enabled, the first few packets are

sent from a port even when IGMP filtering is set to deny those groups on that port. There is no

workaround. (CSCdy82818)

• If an IG MP report packet has two multicast group records, the switch removes or adds interfaces

depending on the order of the records in the packet:

–

If the ALLOW_NEW_SOURCE record is before the BLOCK_OLD_SOURCE record, the

switch removes the port from the group.

–

If the BLOCK_OLD_SOURCE record is before the ALLOW_NEW_SOURCE record, the

switch adds the port to the group.

There is no workaround. (CSCec20128)

• When IGMP snooping is disabled and you enter the switchport block multicast interface

configuration command, IP multicast traffic is not blocked.

The switchport block multicast interface configuration command is only applicable to non-IP

multicast traffic.

There is no workaround. (CSCee16865)