Load-Balancing Methods
By default, LAG hashing uses the source IP, destination IP, source transmission control protocol (TCP)/
user datagram protocol (UDP) port, and destination TCP/UDP port for hash computation. For packets
without a Layer 3 header, the system automatically uses load-balance mac source-dest-mac.
Do not configure IP hashing or MAC hashing at the same time. If you configure an IP and MAC hashing
scheme at the same time, the MAC hashing scheme takes precedence over the IP hashing scheme.
To change the IP traffic load-balancing default, use the following command.
• Replace the default IP 4-tuple method of balancing traffic over a port channel.
CONFIGURATION mode
[no] load-balance {ip-selection [dest-ip | source-ip]} | {mac [dest-mac |
source-dest-mac | source-mac]} | {tcp-udp enable} | {ing-port}
You can select one, two, or all three of the following basic hash methods:
–ip-selection [dest-ip | source-ip] — Distribute IP traffic based on the IP destination or
source address.
–mac [dest-mac | source-dest-mac | source-mac] — Distribute IPV4 traffic based on the
destination or source MAC address, or both, along with the VLAN, Ethertype, source module ID
and source port ID.
–tcp-udp enable — Distribute traffic based on the TCP/UDP source and destination ports.
–ing-port — Distribute traffic based on the port ID of the IP source address.
Changing the Hash Algorithm
The load-balance command selects the hash criteria applied to port channels.
If you do not obtain even distribution with the load-balance command, you can use the hash-
algorithm command to select the hash scheme for LAG, ECMP and NH-ECMP. You can rotate or shift
the 12–bit Lag Hash until the desired hash is achieved.
To change to another algorithm, use the second command.
• Change the default (0) to another algorithm and apply it to ECMP, LAG hashing, or a particular line
card.
CONFIGURATION mode
hash-algorithm {ecmp {crc16 | crc16cc | crc32MSB | crc32LSB | crc–upper |
dest-ip | lsb | xor1 | xor2 | xor4 | xor8 | xor16} hg {crc16 | crc16cc |
crc32MSB | crc32LSB | xor1 | xor2 | xor4 | xor8 | xor16} {hg-seed seed-value}
lag {crc16 | crc16cc | crc32MSB | crc32LSB | xor1 | xor2 | xor4 | xor8 |
xor16} | seed seed-value} linecard slot-id | port-set port-pipe
For more information about algorithm choices, refer to the command details in the IP Routing
chapter of the Dell Networking OS Command Reference Guide.
• Change to another algorithm.
CONFIGURATION mode
hash-algorithm ecmp {crc-upper} | {dest-ip} | {lsb}
Interfaces 417