Dell C1048P Port Extender Networking Configuration Guide for the C9000 Series - Page 435

• Disable a port channel. shutdown When you disable a port channel, all interfaces within the port channel are operationally down also. Load Balancing Through Port Channels The system uses hash algorithms for distributing traffic evenly over channel members in a port channel (LAG). The hash algorithm distributes traffic among electronic commerce messaging protocol (ECMP) paths and LAG members. The distribution is based on a flow, except for packet-based hashing. A flow is identified by the hash and is assigned to one link. In packet-based hashing, a single flow can be distributed on the LAG and uses one link. Packet based hashing is used to load balance traffic across a port-channel based on the IP Identifier field within the packet. Load balancing uses source and destination packet information to get the greatest advantage of resources by distributing traffic over multiple paths when transferring data to a destination. The system allows you to modify the hashing algorithms used for flows and for fragments. The load-balance and hashalgorithm commands are available for modifying the distribution algorithms. 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} Example of the hash-algorithm Command Dell(conf)#hash-algorithm ecmp xor1 lag crc16 Dell(conf)# The hash-algorithm command is specific to ECMP group. The default ECMP hash configuration is crc-lower. This command takes the lower 32 bits of the hash key to compute the egress port. Other options for ECMP hash-algorithms are: • crc-upper - uses the upper 32 bits of the hash key to compute the egress port. • dest-ip - uses destination IP address as part of the hash key. • lsb - always uses the least significant bit of the hash key to compute the egress port. Interfaces 435