Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 842)

812 Multi-Service IronWare Switching Configuration Guide
53-1003036-02
Configuring IP load sharing
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Specifying a slot number using the slot-number variable limits the command to an individual
module.
Specifying a slot number and a network processor ID using the slot-number and np-id variables
limits the command to the ports supported by the specified network processor on the specified
interface module.
This option can also be used in a multi-stage network to avoid the same traffic flow to always use
one path of an ECMP or the same LAG member index at each stage. Using the hash rotate function
the same set of traffic flows forwarded out of one LAG member or ECMP path to the next router can
be distributed across different paths of the LAG member or ECMP path to the next router.
Hash rotate for LAGs and IP load balancing
The hash rotate function provides another option (in addition to hash diversification) for diversifying
traffic flow in a multi-stage network. Using this feature, the ECMP hash index can be rotated by a
specified number of bits after it has been calculated. This allows path selection within IP load
balancing to be more diverse.
To configure hash rotate to LAG index calculations, enter a command such as the following.
Brocade(config)# load-balance hash-rotate 3 all
Syntax: [no] load-balance hash-rotate rotate-number [all | slot-number | slot-number np-id ]
The rotate-number value specifies number of bits between 0 and 7 that you want to rotate the
ECMP hash index value.
The all option applies the command to all ports within the device.
Specifying a slot number using the slot-number variable limits the command to an individual
module.
Specifying a slot number and a network processor ID using the slot-number and np-id variables
limits the command to the ports supported by the specified network processor on the specified
interface module.
NOTE
The hash diversification and hash rotate features can be applied separately or together. Depending
on your network configuration, either or both of these features may need to be configured.
Symmetric load balancing for LAGs
For many monitoring and security applications, bidirectional conversations flowing through the
system must be carried on the same port of a LAG. For Network Telemetry applications, network
traffic is tapped and sent to the Brocade devices, which can load balance selected traffic to the
application servers downstream. Each server analyzes the bidirectional conversations. Therefore,
the Brocade devices must enable symmetric load balancing to accomplish bidirectional
conversations. In addition, firewalls between the Brocade devices can be configured to allow the
bidirectional conversations per link of the LAG. These applications also require symmetric load
balancing on the LAGs between the Brocade devices.
Figure 203 depicts the symmetric load
balancing for LAGs feature.
FIGURE 203 Symmetric load balancing for LAGs