| (iii) | Port Trunking |
Applicable to NAS models with two or more LAN ports only.
The NAS supports port trunking which combines two Ethernet interfaces into one to increase the bandwidth and offers load balancing and fault tolerance (also known as failover). Load balancing is a feature which distributes the workload evenly across two Ethernet interfaces for higher redundancy. Failover is the capability to switch over to a standby network interface (also known as the slave interface) when the primary network interface (also known as the master interface) does not correspond correctly to maintain high availability.
To use port trunking on the NAS, make sure at least two LAN ports of the NAS have been connected to the same switch and the settings described in sections (i) and (ii) have been configured.
Follow the steps below to configure port trunking on the NAS:
| 1. | Click “Settings”. |
| 2. | Select the network interfaces for a trunking group (Ethernet 1+2, Ethernet 3+4, Ethernet 5+6, or Ethernet 7+8). Choose a port trunking mode from the drop-down menu. The default option is Active Backup (Failover). |
| 3. | Select a port trunking group to use. Click “Apply”. |
| 4. | Click the Edit button under “IP Address” to edit the network settings. |
|
Note: Make sure the Ethernet interfaces are connected to the correct switch and the switch has been configured to support the port trunking mode selected on the NAS. |
The port trunking options available on the NAS:
|
Field |
Description |
Switch Required |
|
Balance-rr (Round-Robin) |
Round-Robin mode is good for general purpose load balancing between two Ethernet interfaces. This mode transmits packets in sequential order from the first available slave through the last. Balance-rr provides load balancing and fault tolerance. |
Supports static trunking. Make sure static trunking is enabled on the switch. |
|
Active Backup |
Active Backup uses only one Ethernet interface. It switches to the second Ethernet interface if the first Ethernet interface does not work properly. Only one interface in the bond is active. The bond’s MAC address is only visible externally on one port (network adapter) to avoid confusing the switch. Active Backup mode provides fault tolerance. |
General switches |
|
Balance XOR |
Balance XOR balances traffic by splitting up outgoing packets between the Ethernet interfaces, using the same one for each specific destination when possible. It transmits based on the selected transmit hash policy. The default policy is a simple slave count operating on Layer 2 where the source MAC address is coupled with destination MAC address. Alternate transmit policies may be selected via the xmit_hash_policy option. Balance XOR mode provides load balancing and fault tolerance. |
Supports static trunking. Make sure static trunking is enabled on the switch. |
|
Broadcast |
Broadcast sends traffic on both network interfaces. This mode provides fault tolerance. |
Supports static trunking. Make sure static trunking is enabled on the switch. |
|
IEEE 802.3ad (Dynamic Link Aggregation) |
Dynamic Link Aggregation uses a complex algorithm to aggregate adapters by speed and duplex settings. It utilizes all slaves in the active aggregator according to the 802.3ad specification. Dynamic Link Aggregation mode provides load balancing and fault tolerance but requires a switch that supports IEEE 802.3ad with LACP mode properly configured. |
Supports 802.3ad LACP |
|
Balance-tlb (Adaptive Transmit Load Balancing) |
Balance-tlb uses channel bonding that does not require any special switch. The outgoing traffic is distributed according to the current load on each Ethernet interface (computed relative to the speed). Incoming traffic is received by the current Ethernet interface. If the receiving Ethernet interface fails, the other slave takes over the MAC address of the failed receiving slave. Balance-tlb mode provides load balancing and fault tolerance. |
General switches |
|
Balance-alb (Adaptive Load Balancing) |
Balance-alb is similar to balance-tlb but also attempts to redistribute incoming (receive load balancing) for IPV4 traffic. This setup does not require any special switch support or configuration. The receive load balancing is achieved by ARP negotiation sent by the local system on their way out and overwrites the source hardware address with the unique hardware address of one of the Ethernet interfaces in the bond such that different peers use different hardware address for the server. This mode provides load balancing and fault tolerance. |
General switches |
