Configuring a link group
Link groups include ISP gateways your company uses for outbound traffic. Grouping links reduces the risk of outages and provisions additional bandwidth to relieve potential traffic congestion. See Using link groups.
The link group configuration specifies the load balancing algorithm and the gateway routers in the load balancing pool. You can enable LLB options, such as persistence rules and proximity routes.
Before you begin:
- You must have configured gateway links and persistence rules and before you can select them in the link group configuration.
- You must have Read-Write permission for Link Load Balance settings.
After you have configured a link group configuration object, you can select it in the link policy configuration.
To configure a link group:
- Go to Link Load Balance > Link Group.
- Click Create New to display the configuration editor.
- Complete the configuration and add members as described in Link group configuration.
- Save the configuration.
The configuration page displays the Link Group tab.
Settings | Guidelines |
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Name |
Configuration name. Valid characters are Note: After you initially save the configuration, you cannot edit the name. |
Address Type |
IPv4 Note: IPv4 is selected by default, and cannot be changed. |
Route Method |
|
Persistence |
Select a persistence configuration. Optional. |
Proximity Route |
|
Add member |
|
Name |
Configuration name. Valid characters are After you initially save the configuration, you cannot edit the name. |
Gateway |
Select a gateway configuration object. See Configuring gateway links. |
Weight |
Assigns relative preference among members—higher values are more preferred and are assigned connections more frequently. The default is 1. The valid range is 1 to 255. All load balancing methods consider weight, except spillover, which uses its own priority configuration. Servers are dispatched requests proportional to their weight, relative to the sum of all weights. The following example shows the effect of weight on WRR:
For other methods, weight functions as a tie-breaker. For example, with the Least Connection algorithm, requests are sent to the server with the least connections. If the number of connections is equal, the request is sent to the server with the greater weight. For example:
The next request is sent to Server B. |
Spillover Priority |
Assigns a priority to the link when using a spillover load balancing method. Higher values have greater priority. When a spillover method is enabled, the system dispatches new connections to the link that has the greatest spillover priority until its threshold is exceeded; then it dispatches new connections to the link with the next greatest priority until its threshold is exceeded, and so on. If multiple links in a link group have the same spillover priority, the system dispatches new connections among those links according to round robin. The default is 0. The valid range is 0-9. |
Status |
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Backup |
Enable to designate the link as a backup member of the group. All backup members are inactive until all main members are down. |