MR57 Dual Uplink High Availability
Overview
MR57 has two Ethernet ports and can support 802.3af/802.3at/802.3bt/UPoE.
There are three PoE operation modes:
- Single PoE: only one Ethernet port receives PoE.
- Dual PoE (power sharing mode): both Ethernet ports receive PoE. The power is split on both ports, not necessarily even.
- Dual PoE (dual-uplink mode): both Ethernet ports receive PoE. If PoE on one of the Ethernet ports fails, MR57 will seamlessly switch to the remaining Ethernet port without adversely affecting wireless clients' connectivity.
In power-sharing mode, the power draw is not split equally among the two PoEs. MR57 tends to draw more power from the PoE with higher voltage. For example, if MR57 is connected to two 802.3af PSE ports and draws 23W in total, MR57 could draw more than 802.3af power from one PoE port (18W) while little from the other (5W). Some switch ports might shut down the port if the PD draws more power than the switch support, and MR57 will reboot. To solve this problem, MR57 needs to set the maximum power draw from the PSE depending on the classified PD type or LLDP/CDP negotiation results.
In the High-Availability mode, MR57 will not reboot or drop any wireless clients if one of the ports loses power.
Minimum firmware support for Dual Uplink High Availability is MR 30.1
Power Source Options 
MR57 can be powered by dual M-Gig 802.3bt capable PoE ports. The two Ethernet ports can combine the power of two 802.3af/at power to provide 802.3at/bt. The AP can operate at its full capacity when powered by a single 802.3bt power at full capacity. All the AP radios will run at full capacity; however, the USB port will be disabled when powered by a single 802.3at power.
The table below indicates the different modes of PoE power input and the expected operation of the AP.
|
PoE0 |
PoE1 |
2.4GHz |
5GHz |
6GHz |
Scan |
IoT |
USB |
|
AF |
None |
Not Supported and AP does not power up |
|||||
|
AF |
AF |
4x4 |
4x4 |
4x4 |
ON |
ON |
OFF |
|
AT |
None |
4x4 |
4x4 |
4x4 |
ON |
ON |
OFF |
|
AT |
AT |
4x4 |
4x4 |
4x4 |
ON |
ON |
ON |
|
BT |
None |
4x4 |
4x4 |
4x4 |
ON |
ON |
ON |
|
BT |
BT |
4x4 |
4x4 |
4x4 |
ON |
ON |
ON |
MR57 APs can be powered by the PoE power in different modes, as mentioned above, when using a PoE-capable switch. MR57 can also be powered by a single 802.3bt capable PoE injector MA-INJ-6 - MerakimultiGigabit 802.3bt Power over Ethernet Injector. It can also be powered by an AC power adaptor MA-PWR-50WACMeraki AC Adapter for MR Series.
High Availability
In High Availability mode, the MR57 can switch between the ethernet ports without rebooting or dropping any wireless clients. This high availability allows for seamless failover from the primary to the secondary uplink port. The MR57 has dual ethernet ports ETH0 and ETH1 with separate assigned MAC addresses. In High availability, the MR57 will check the link state of the redundant interface every 5 seconds. In the event of a failover, the MR57 will switch the primary uplink from ETH0 to ETH1.
Note: Power sharing mode is the default mode of the MR57. When High Availability is configured, the power is not shared between links. If an MR57 uses High Availability and both ports receive 802.3at, the MR57 will register a single 802.3at power source. Reference the required power source combinations for operation in the table below.
|
PoE0 |
PoE1 |
2.4GHz |
5GHz |
6GHz |
Scan |
IoT |
USB |
|
AF |
AF |
Not Supported and AP does not power up |
|||||
|
AT |
AT |
4x4 |
4x4 |
4x4 |
ON |
ON |
OFF |
|
AT |
BT |
4x4 |
4x4 |
4x4 |
ON |
ON |
ON |
|
BT |
BT |
4x4 |
4x4 |
4x4 |
ON |
ON |
ON |
Configuration
Prerequisites
Port Profiles
If the MR57 is configured with port profiles, ensure the secondary port is enabled for seamless failover.
For additional information on configuring port profiles on APs, please refer to the following link.
Link Aggregation
High Availability requires link aggregation to be enabled on both ethernet ports. This allows the MR57 to monitor the link operational state of the secondary port.
Please refer to this link for additional information on configuring link aggregation on MRs.
Mode Selection
- Mode selection can be made on the AP details page Wireless > Monitor > Access points.
- Select the MR57
- Within the Access point view page, change the Ethernet Power Mode to High Availability.
- Save the configuration
Note: Power sharing mode is the default mode of the MR57. When High Availability is configured, power is not shared between the links. For example, if two ports receive 802.3at, AP operates on a single 802.3at. Refer to the above power distribution.
Below is a table summary of the configuration states:
| Link Aggregation State | Mode | Use case |
| Enabled | Power Sharing | Additional power is required. |
| Enabled | High Availability | Power and Data Redundancy. |
| Disabled | Power Sharing | No benefits, feature is disabled. |
| Disabled | High Availability | No benefits, feature is disabled. |