Cisco Cisco IOS Software Release 12.2(53)SE

Traffic on EtherChannel ports is not perfectly load-balanced. Egress traffic on EtherChannel ports 
are distributed to member ports on load balance configuration and traffic characteristics like MAC 
or IP address. More than one traffic stream might map to same member ports, based on hashing 
results calculated by the ASIC.

If this happens, traffic distribution is uneven on EtherChannel ports. 

Changing the load balance distribution method or changing the number of ports in the EtherChannel 
can resolve this problem. Use any of these workarounds to improve EtherChannel load balancing:

for random source-ip and dest-ip traffic, configure load balance method as src-dst-ip

for incrementing source-ip traffic, configure load balance method as src-ip

for incrementing dest-ip traffic, configure load balance method as dst-ip

Configure the number of ports in the EtherChannel so that the number is equal to a power of 2 
(for example, 2, 4, or 8)

For example, with load balance configured as dst-ip with 150 distinct incrementing destination 
IP addresses, and the number of ports in the EtherChannel set to either 2, 4, or 8, load 
distribution is optimal. (CSCeh81991)

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)

After you change the access VLAN on a port that has IEEE 802.1x enabled, the IP phone address is 
removed. Because learning is restricted on IEEE 802.1x-capable ports, it takes approximately 30 
seconds before the address is relearned. No workaround is necessary. (CSCea85312)

If an IGMP 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)