Loadbalacing

Hi,

there exist some limitations in load balancing in a routed environment (IP routed). Most bonding modes are optimized in communication within the same VLAN or subnet only. Balance-rr (mode 0), broadcast (mode 3), balance-tlb (mode 5) and balance-alb (mode 6) have problems to boost the performance, if a gateway (which have exactly one MAC address) is used. Only 802.3ad (mode 4) or balance-xor (mode 2) can help here. But in the default configuration the calculation method is made by selection the interface using the MAC address of the communication partner. In a routed environment with many VLANs (e.g. if layer-3 switches are used), this is always the gateway of the VLAN, and so every time the same interface of the bond is used (whatever how many interfaces are in the bond). Using calculation of the interface by IP address and perhaps TCP port can here increase the speed dramatic, if there are several endpoints (TCP sockets) in other VLANs/IP subnets to feed. This is normal in bigger IT environments.
The behavior can be set/change by the parameter xmit_hash_policy (layer3+4) instead of the default (layer2).

Can this parameter be modified in DSS? The speed benefit would be very high!

So long
Michael

Great suggestion! - I will ask our development team . We will need time though as many projects are scheduled for this year already.

http://www.linux-foundation.org/en/Net:Bonding