14.1.1 Frame Alignment Legacy Mode

Products PMP
1

I'm hoping one of the Cambium guys can clear up something for us. The Configuration and User Guide for 14.1.1 seems to indicate that the Frame Alignment Legacy Mode option is only needed if there are co-located PMP100 APs but the User Interface on the device doesn't also give this indication. So is it ever neceaasry to enable this option if there are co-located PMP450 APs? Thanks.

2

Hello Des Chambers!

First, to answer your question, yes the Frame Alignment Legacy Mode also applies to co-locating 450 APs which are on different software versions (Mode configuration can be determined by the web management interface tables you mentioned).  

The User Guide will be refreshed to clarify that Frame Alignment Legacy Mode operates in the following fashion:

Frame Alignment Legacy Mode

In order to facilitate field hardware upgrades/replacements, "Frame Alignment Legacy Mode" has been added to newer software releases to allow for co-location with radios running older Canopy versions which cannot be upgraded at the same time, or to allow for slow rollout of upgrades on a per-sector basis, while maintaining compatibility with nearby sectors.

The best solution for resolving frame alignment issues for co-location is to maintain deployment of the latest software builds.

The web management interface contains a table (located at Configuration > Radio > Advanced) to reference which setting is appropriate for your network based on software versions and synchronization sources:

Figure 3 Frame Alignment Legacy Mode (non-900 MHz)

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Figure 4 Frame Alignment Legacy Mode (900 MHz)

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Please refer to the AP’s web management interface at Configuration > Radio > Advanced to determine the setting for the Frame Alignment Legacy Mode based on your network deployment. Note that this table differs between 900 MHz and 5 GHz hardware.

 

When utilizing Frame Alignment Legacy Mode, legacy radios must remain on a fixed synchronization source, or the Frame Alignment Legacy Mode parameter must be adjusted to accommodate the changes of the legacy radio synchronization source. New devices with Frame Alignment Legacy Mode set to ON (Mode 1 or Mode 2) will remain in synchronization with the legacy radio even if its own synchronization source is changed.

Table 12 Frame Alignment Legacy Mode attribute

Attribute

Meaning

Frame Alignment Legacy Mode

In order to align the frame start of co-located systems, the Frame Alignment Legacy Mode has to be selected from following options:

Frame Alignment Legacy Mode

Behavior (non-900 MHz radios)

Behavior (FSK 900 MHz radios)

OFF

By default frame start is aligned with devices with Timing Port synchronization

If the synchronization source changes (due to Autosync or otherwise) the radio will dynamically adjust its frame start to maintain alignment with the default frame start timing

By default frame start is aligned with FSK 900 MHz devices with Timing Port synchronization

If the synchronization source changes (due to Autosync or otherwise) the radio will dynamically adjust its frame start to maintain alignment with the default frame start timing

ON (Mode 1)

The radio will align with devices running software versions from 12.0 to 13.4.

The radio will align with FSK 900 MHz devices running software versions from 12.0 to 13.4.

ON (Mode 2)

N/A

The radio will align with FSK 900 MHz devices with software versions 11.2 or older.

 I hope this helps!

-Marty

1 Like
3

Hi Marty,

We use Sync over the Power Port for all our APs but occasionally an AP might fail over to iGPS for some reaon. How would that scenario affect the timing in this case? 

Thanks for the quick response.

Des.

4

Would this have any impact on PMP320 colocation?