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Port Trunking Modes
Round-robin policy
- Transmits packets in sequential order from the first available slave through
the last. This mode provides load balancing and fault tolerance.
Active-backup policy
- Only one half of the bond is active at once. The other half becomes active if
and only if the active slave fails. The bond’s MAC address is externally visible on only one port to
avoid confusing the switch. This mode provides fault tolerance.
XOR policy
- Transmit is based on the source MAC address XOR’d with destination MAC address
and modulo slave count. This selects the same slave for each destination MAC address. XOR
provides load balancing and fault tolerance.
Broadcast policy
- Transmits everything on all slave interfaces. This mode provides fault tolerance.
Dynamic link aggregation
- Creates aggregation groups that share the same speed and duplex
settings. Utilizes all slaves in the active aggregator according to the 802.3ad specification. Switch
must support IEEE 802.3ad Dynamic link aggregation to use this mode.
TLB
- Channel bonding that does not require any special switch support. Outgoing traffic is
distributed according to the current load (computed relative to the speed) on each slave. Incoming
traffic is received by the current slave. If the receiving slave fails, another slave takes over the
MAC address of the failed receiving slave.
ALB
- Adaptive load balancing includes balance-tlb plus receive load balancing (rlb) for IPV4 traffic
and does not require any special switch support. The receive load balancing is achieved by ARP
negotiation. The bonding driver intercepts the ARP Replies sent by the local system on their way
out and overwrites the source hardware address with the unique hardware address of one of the
slaves in the bond such that different peers use different hardware addresses for the server.
