Understanding txload and rxload in an etherchannel

[toolman]

I have two interfaces bundled in an etherchannel. From the reading I've done, for individual ports, rxload + txload should never exceed 255/255. I have one of the interfaces exceeding that, but the average rxload + txload of the etherchannel is staying below 255/255. I'm just curious how one link in an etherchannel can be exceeding 100% load? What is being measured in this case?

Device is a WS-C4510R+E

Interface 1: reliability 255/255, txload 131/255, rxload 250/255

Interface 2: reliability 255/255, txload 5/255, rxload 22/255

Portchannel: reliability 255/255, txload 68/255, rxload 137/255 (noticed this is the average of two interfaces)

interface GigabitEthernet1/1
switchport access vlan 100
switchport trunk allowed vlan 101,102,103
switchport mode trunk
speed 1000
duplex full
no snmp trap link-status
channel-group 1 mode active
spanning-tree portfast edge
service-policy output Interlink-PO-Priority
end

interface GigabitEthernet1/2
switchport access vlan 100
switchport trunk allowed vlan 101,102,103
switchport mode trunk
speed 1000
duplex full
no snmp trap link-status
channel-group 1 mode active
spanning-tree portfast edge
service-policy output Interlink-PO-Priority
end

interface Port-channel1
switchport
switchport access vlan 100
switchport trunk allowed vlan 101,102,103
switchport mode trunk
speed 1000
duplex full
service-policy output Interlink-PO-Police
end

[balaji.bandi]

It all depends on what kind of LB method is used. Check some references on how the hashing works—change the LB method to meet the requirement. Again, it all depends on traffic. 

https://www.cisco.com/c/en/us/support/docs/lan-switching/etherchannel/12023-4.html

In my experience, some TCP sessions are established for a long time and then use the same path until the TCP session closes.

[Joseph W. Doherty]

The TX and RX load ratios are based on actual average load over some time period (default, I recall, 5 minutes) vs. what device believes is the maximum available bandwidth using a scale from zero to 255.

The ratio will not exceed 255, but a load percentage can exceed 100% if the computation uses an incorrect value for maximum available bandwidth.

For example if a dual port channel believes its aggregate bandwidth is only one port's, the port channel could have up to 200% usage.