Dell Force10 S4820T S4820T Configuration Guide - Page 457

C-Series and S-Series load-balancing For LAG hashing on C-Series and S-Series, the source IP, destination IP, source TCP/UDP port, and destination TCP/UDP port are used for hash computation by default. For packets without a Layer 3 header, FTOS automatically uses load-balance mac source-dest-mac. IP hashing or MAC hashing should not be configured 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 on the C-Series and S-Series, use the following command: Command Syntax [no] load-balance {ip-selection [dest-ip | source-ip]} | {mac [dest-mac | source-dest-mac | source-mac]} | {tcp-udp enable} | {ing-port} Command Mode Purpose CONFIGURATION Replace the default IP 4-tuple method of balancing traffic over a port channel. 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 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 TCP/UDP source and destination ports. ing-port -Distribute traffic based on the port ID of the IP source address. Hash algorithm The load-balance command discussed above selects the hash criteria applied to port channels. If even distribution is not obtained with the load-balance command, the hash-algorithm command can be used to select the hash scheme for LAG, ECMP and NH-ECMP. The 12 bit Lag Hash can be rotated or shifted till the desired hash is achieved. The nh-ecmp option allows you to change the hash value for recursive ECMP routes independently of non-recursive ECMP routes. This option provides for better traffic distribution over available equal cost links that involve a recursive next hop lookup. Interfaces | 457