Load Balancing Modems on a capable Cradlepoint Router
Products Supported: Series 3. Click here to identify your router.
Firmware Version: 5.3.0 - for information on upgrading firmware, click here.
Firmware version 6.0 has been released and introduces a vastly improved GUI for all current Series 3 routers. Cradlepoint has created new Knowledge Base articles with updated screen shots and instructions for the new GUI layout. As a result, this article has received its final update. To view the version of this Knowledge Base article for Firmware 6.0 and Later please click here.
This article explains how to configure the Load-Balancing feature on capable Series 3 Cradlepoint routers.
Load-Balancing allows multiple WAN connections to be used concurrently to improve bandwidth reliability with a Cradlepoint Series 3 router. This feature effectively increases the data transfer throughput by using any connected modem interfaces consecutively. Please see the "High Level Explanation" section of this article for a high level explanation of Cradlepoint's Load Balancing implementation.
This article describes the necessary steps to enable Load Balancing on your Series 3 Cradlepoint router.
MBR1400 Load-Balancing Limitations
There are 3 USB & 2 ExpressCard connectors for modems on a MBR1400, which are provided to give users the maximum flexibility in choosing modems to use with the Series 3 Router. The limitations of their use are outlined below:
AER2100 Load-Balancing Limitations
- The power budget of the MBR1400 allows a maximum of 2 cellular modems to be actively connected and transmitting data at one time. These 2 modems can be any combination of LTE/WiMAX/HSPA+/EVDO.
- Version 3.3.0 or greater is required to support 2 simultaneous LTE or WiMAX modems.
- 2 additional modems are allowed if configured in a non-connected/standby mode.
- A “dual-mode” modem typically can only connect to one mode at a time and counts as 1 modem load.
There are 2 Modem Slots & 2 USB Ports on the AER2100 to provide flexibility in connection options. With the standard 3.3V power supply the AER2100 is capable of load balancing 2 LTE modems (either in the USB or Modem Slots). With the 4V upgraded power supply, the AER2100 can load balance an additional LTE modem for a total of 3.
High Level Explanation
It is important to understand that the Cradlepoint router does not perform aggregate channel bonded load balancing. Cradlepoint routers attempt to balance modem use based on available bandwidth on attached load balanced modems. However, the Cradlepoint router will not sum the available bandwidths of attached load balanced modems, nor will summed bandwidth be reflected in an online speed test.
Each modem (air card) attached to the router that is load balanced has an associated bandwidth value. For example, let's say modem A has an available bandwidth of 1Mbps and modem B has an available bandwidth of 2Mbps. When an IP connection (session) is generated from a computer attached to the router, the router will assess the available bandwidth of each modem and place the connection on the modem with the greatest available bandwidth (in this example, this would be modem B), then subtract the connection's required bandwidth from the available bandwidth on modem B. Only Modem B will be utilized for this IP connection. As new IP connections (session) are generated from a computer, the router will again check modem A and modem B for available bandwidth. If modem B still has more available bandwidth than modem A, then modem B will again be utilized for this new IP connection until the connection is terminated. The available bandwidth of each modem will be checked each time new IP connections are generated and modem A will not be ever be utilized unless it has greater available bandwidth than modem B.
Based on the above description, one can see that the attached load balanced modems are not evenly utilized, nor is the available bandwidth of the modems summed together. This issue can be accentuated when there is a very large difference in the available bandwidth of the two attached modems, for instance, an attached 4G modem in combination with an attached 3G modem. In cases such as this, the 3G modem may be only slightly utilized, or possibly not at all, depending on the volume of IP connections that are generated from attached computers. However, services such as bit torrents will usually utilize both modems very well due to the fact that multiple individual IP connections are spawned while a torrent is downloading.
Configuration Difficulty: Intermediate
- Step 1: Log into the router's Setup Page. For help with logging in please click here.
- Step 2: Click on the Internet tab and select Connection Manager from the drop-down menu.
- Step 3: Within the "WAN Interfaces" list, check the boxes in the Load Balancing column to specify which devices you would like to load balance across.
- Step 4: Click on the Internet tab, and select WAN Affinity/Load Balancing from the drop-down menu.
- Step 5: Click the down arrow beside the Load Balance Algorithm field to select the needed option.
- Spillover: This was the default algorithm in the version 3 firmware. Load is always given to devices with the most available bandwidth. The estimated bandwidth rate is based on a combination of the upload and download configuration values and the observed capabilities of the device.
- Round-Robin: Evenly distribute each session to the available WAN connections.
- Rate: Distribute load based on the current upload and download rates. A WAN device's upload and download bandwidth values can be set in the Connection Manager page.
- Device Usage: This mode works in concert with the Data Usage feature. The router will make best effort to keep data usage between interfaces at a similar percentage of the assigned data cap in the Data Usage rule for each interface, rather than distributing sessions based solely on bandwidth. For proper function you need to create data usage rules for each WAN device you will be load balancing. Make certain to select the "Use with Load Balancing" checkbox in the Data Usage rule editor.
- Step 6: Press the Apply button to submit the setting.
Published Date: 12/16/2014
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