Dell Force10 S4820T FTOS Command Reference Guide - Page 518

www.dell.com | support.dell.com The hash value calculated with the hash-algorithm command is unique to the entire chassis. The hash algorithm command with the line card option changes the hash for a particular line card by applying the mask specified in the IPSA and IPDA fields. The line card option is applicable with the lag-hash-align microcode only (refer to cam-profile (Config)). Any other microcode returns an error message as follows: Message 1 FTOS(conf)#hash-algorithm linecard 5 ip-sa-mask ff ip-da-mask ff Message 2 % Error: This command is not supported in the current microcode configuration. In addition, the linecard number ip-sa-mask value ip-da-mask value option has the following behavior to maintain bi-directionality: • When hashing is done on both IPSA and IPDA, the ip-sa-mask and ip-da-mask values must be equal. (Single Linecard) • When hashing is done only on IPSA or IPDA, FTOS maintains bi-directionality with masks set to XX 00 for line card 1 and 00 XX for line card 2 (ip-sa-mask and ip-da-mask). The mask value must be the same for both line cards when using multiple line cards as ingress (where XX is any value from 00 to FF for both line cards). For example, assume traffic is flowing between linecard 1 and linecard 2: Message 3 hash-algorithm linecard 1 ip-sa-mask aa ip-da-mask 00 Message 4 hash-algorithm linecard 2 ip-sa-mask 00 ip-da-mask aa The different hash algorithms are based on the number of Port Channel members and packet values. The default hash algorithm (number 0) yields the most balanced results in various test scenarios, but if the default algorithm does not provide a satisfactory distribution of traffic, then use the hash-algorithm command to designate another algorithm. When a Port Channel member leaves or is added to the Port Channel, the hash algorithm is recalculated to balance traffic across the members. On TeraScale if the keyword ECMP or LAG is not entered, FTOS assumes it to be common for both. If the keyword ECMP or LAG is entered separately, both should fall in the range of 0 to 23 or 24 to 47 since compression enable/disable is common for both. TeraScale and ExaScale support the range 0-47. The default for ExaScale is 24. For EtherScale, only the range 0 to 15 is valid; 16 to 47 is considered as 15. Compression Enabled 0-11 rotate [0 - 11] 518 | Equal Cost Multi-Path