PMP 450 Ask the Experts May 13

When will the 4.9ghz 450 be available?

What’s the total frequency band that it will be able to use in the USA?


@paulchops wrote:

On the PMP 450....  we are attempting to read the value that the SMs are set to as far as 1x/2x/4x/6x/8x using OID

1.3.6.1.4.1.161.19.3.3.2.85.   It returns no such object.  The notes say "Engineering Use Only".   

We can rate the actual connected rate using: 1.3.6.1.4.1.161.19.3.2.2.20.  We use both of these variables in our custom analysis tool.

Is there a way to get the value (setting in the radio for Adaptrate) on PMP 450?  if not today, is is coming?

With the 100 series, platform we can do this without problem.

Paul McCall, PDMNet / Florida Broadband


Paul,

Thanks for bringing this to our attention. PMP 450 does not allow configuration of the Rate Adapt parameter, so all 450 radios have a max rate adapt of 8x. So you do not need to read this object to know what it is configured for. But I can open an issue to get this item read only for PMP 450.

There are also integer rate adapt readings below if you’d rather use them.

-Charlie

AP:

Name

linkAdaptRateLowPri

OID

.1.3.6.1.4.1.161.19.3.1.4.1.91

MIB

WHISP-APS-MIB

Syntax

INTEGER {noSession(0), rate1X(1), rate2X(2), rete3X(3), rate4X(4), rate6X(6), rate8X(8)}

Name

linkAdaptRateHighPri

OID

.1.3.6.1.4.1.161.19.3.1.4.1.92

MIB

WHISP-APS-MIB

Syntax

INTEGER {noHighPriorityChannel(-1), noSession(0), rate1X(1), rate2X(2), rete3X(3), rate4X(4), rate6X(6), rate8X(8)}

SM:

Name

adaptRateLowPri

OID

.1.3.6.1.4.1.161.19.3.2.2.128

MIB

WHISP-SM-MIB

Syntax

INTEGER {noSession(0), rate1X(1), rate2X(2), rete3X(3), rate4X(4), rate6X(6), rate8X(8)}

Name

adaptRateHighPri

OID

.1.3.6.1.4.1.161.19.3.2.2.129

MIB

WHISP-SM-MIB

Syntax

INTEGER {noHighPriorityChannel(-1), noSession(0), rate1X(1), rate2X(2), rete3X(3), rate4X(4), rate6X(6), rate8X(8)}

In regards to 900MHz 450, please attempt to release a similar form factor to existing 900MHz 100 series APFs.

The existing APF sits nicely on top of a universal mounting bracket.  The easier you make it to deploy or 'cut over' from the old system, the faster we will purchase.


@Sean Heskett wrote:
When will the 4.9ghz 450 be available?

What's the total frequency band that it will be able to use in the USA?

Sean,

PMP 450i will support the 4.9 GHz band in the US, and we will launch this in August.

The product will support 4.900 to 5.925 GHz, and support every FCC band in the US.  At launch, we expect to have a grant for 4.9 (4940-4990 MHz) and 5.8 (5725-5850 MHz), with the remaining bands to be added via a software release in the fall (due to the process it takes the FCC to issue approval).  

In total, we expect the product to be capable of 4.9, 5.1, 5.2, 5.4 and 5.8 GHz frequency bands in the US.


@Brian Sullivan wrote:

In regards to 900MHz 450, please attempt to release a similar form factor to existing 900MHz 100 series APFs.

The existing APF sits nicely on top of a universal mounting bracket.  The easier you make it to deploy or 'cut over' from the old system, the faster we will purchase.


Brian,

At this time, we are planning to release only a connectorized version of the AP and SM for PMP 450i 900MHz.  We are not planning a version with integrated filters.  We are taking steps to make the migration as easy as possible, and will release documentation on how to do this prior to product launch.

I am having issues with my PMP 450 SMsnot consistently responding to pings. There are some times where I can ping a device connected to the same switch as the PMP 450 SM but I can't ping the PMP 450 SM. Is this a known issue?

I hope you're not tired of hearing about 3.65ghz.

It sounds like a portion of 3.5ghz will be opened up, using rules that are not entirely clear to me yet, but at least part of the band will require the AP to talk to a geolocation database.  Will the existing 3.65ghz 450 hardware support 3.5ghz?  Will it be able to do the geolocation and/or other requirements for the new rules? 


@joepuh77 wrote:

I am having issues with my PMP 450 SMs not consistently responding to pings. There are some times where I can ping a device connected to the same switch as the PMP 450 SM but I can't ping the PMP 450 SM. Is this a known issue?


There are a number of things that can cause this, but the most common is a mismatch between bridge timeout on the AP and ARP timeout on a switch/router above the AP.    The AP doesn't forward unicast packets whose destinations aren't found in its bridging table.  This has always been this way in order to limit consuming the RF spectrum with (what could be) invalid packets.

There are two ways to address this.  First is to have the bridge timeout value on the AP (on the Configuration->General page) configured to be longer than the ARP cache timeout on the upstream router.   The second is to enable a setting on the AP called "Packet Flooding" (also on the Configuration->General page).   Setting this to enabled will allow forwarding of unknown unicast packets to all of the SMs and then, when the device replies, it will be learned in the bridge and operation will continue as normal.

This setting takes affect on the fly when you turn it on and off, so next time you see the problem, try turning this on, then try to connect to the SM.  If it works, then it indicates you have a cache timeout mismatch occurring.

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@adammoffett wrote:

I hope you're not tired of hearing about 3.65ghz.

It sounds like a portion of 3.5ghz will be opened up, using rules that are not entirely clear to me yet, but at least part of the band will require the AP to talk to a geolocation database.  Will the existing 3.65ghz 450 hardware support 3.5ghz?  Will it be able to do the geolocation and/or other requirements for the new rules? 


Never tired of the 3 GHz band... there's a LOT going on with it these days.

We are also unclear about some of the new rules surrounding the additional spectrum and the SAS (Spectrum Access System). As we figure out some things, and get the FCC to clarify their position on other aspects, we will keep everyone informed as much as possible.

Regarding the current PMP 450 at 3.65 GHz, the hardware was built to be capable of supporting the additional frequencies (i.e. all the way down to 3.55 GHz).  What's as yet unclear is exactly how we will support the SAS that will be implemented.  We fully expect to be capable of supporting this additional spectrum.

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Will a current 450 5ghz sm be able to talk to the new 450i in the 5.4 and 5.8 bands?


@Sean Heskett wrote:
Will a current 450 5ghz sm be able to talk to the new 450i in the 5.4 and 5.8 bands?

Yes, it absolutely will.  However, this feature won't be there at launch. Interoperability with PMP 450 will be implemented in Release 14.1, which is expected within a few months of the PMP 450i release.

When will I be able to sync PMP450 ap's and ePMP ap's?


@Kevin Simms wrote:

When will I be able to sync PMP450 ap's and ePMP ap's?


Hi, 

There is ongoing work to allow ePMP to sync with PMP 100s. This is planned for a late summer release.

For PMP 450, there are additional technical challenges we have to overcome on ePMP to sync. We have not planned work on this yet.

Thanks,

Sriram 


@adammoffett wrote:

Ok thanks.  I want to hammer on the NLOS question a little more because right at the moment it's near and dear to me.

Has the 3.65ghz PMP450 been compared to 3.65ghz WiMax products for NLOS performance, and if so, how did it compare?  Assuming we're using the (current) legal FCC limit of +40dbm EIRP, it seems the 450 should be able to match the output of a wimax BS.  Meanwhile the SM+reflector has 6-7dbi more gain that a typical WiMax CPE.  On the surface, it sounds like the 450 should be better than wimax because we've got the same output from the AP, and more receive gain at the CPE, but I've got wimax (and one LTE) vendors telling me that their product is better for NLOS.

I'm wondering if Cambium has done it's own testing on this topic.


In the scenario above, in LOS conditions PMP 450 will perform better than PMP320 because of the higher link budget. Tests done by Cambium show a better range for some NLOS PMP 320 deployments, but a consistent better throughput for PMP 450 deployments in the same conditions.

Thanks everyone! The development team will be back at 9PM tonight Central time, but feel free to post your questions here throughout the day.

My Questions are for the PMP 450 900mhz:

- How well will the AP and SM cope with interferiance (both self and exsternal)?

- Will the AP and SM have inbuilt interferance filters or filtering?

- Will there be some kind of GPS sync allowing for frequiency re-use in 4 and 6 gang configuration?

- Willl there be  MIMO and in what conguration?

- What antenna selection wll be avalible for the PMP450 900, both for SM and AP?

Lastly, please dont bring back that god alful reflector dish... The Fore 110 was a great step forward.

Thanks.

Hello,

I have three questions:

First: The new frame utiliization statistics in 13.4 build 7 is it valid/accurate to use them as a rough guide to capacity/use on an AP. IE: If the downlink frame utilization is 80% it would be a good rough estimate it's roughly 80% used if the remaining customers/new customers meet the same average modulations/specs of the existing customers.  Up till now we've been determinening AP's capacity through the planning guide and a dart board (to guess average customer modulation per data bit).

Second: The high priority vs low priority queue. If I have two SM's one configured with Sustained Downlink Data Rate of 6000 and the Low Priority Downlink CIR set to the default 0 and another SM with Sustained Downlink Data Rate of 6500 but with a High Priority channel enabled and High Priority Downlink CIR set to 500 and Low Priority Downlink CIR set to 6000 does the AP give priority to the SM with a setting in low priorty uplink/downlink over the SM with 0 in the CIR? Or is the only difference between the SM's at that point that one has a high priority 500 Kbit channel?

Last question: The high priority channel, is there a negative effect to provisioniong larger then needed high priority channels if they are not being fully used? IE: giving an SM that needs 90 Kbits for a VoIP call in DSCP 46 a high priority channel of 100 kbits vs 500 kbits. (Assuming they only use 90 kbits not that they use more then that)

Thanks for taking the time and keep up the good work. Many of changes in 13.4 seem very nice and feature improvements really help the argument for staying with Cambium equipment.

Tim

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The engineers will be joining us in a few minutes. We will respond to all open questions in the queue, but feel free to post your questions at any time.


@Timothy Alexander wrote:

Hello,

I have three questions:

First: The new frame utiliization statistics in 13.4 build 7 is it valid/accurate to use them as a rough guide to capacity/use on an AP. IE: If the downlink frame utilization is 80% it would be a good rough estimate it's roughly 80% used if the remaining customers/new customers meet the same average modulations/specs of the existing customers.  Up till now we've been determinening AP's capacity through the planning guide and a dart board (to guess average customer modulation per data bit).

Second: The high priority vs low priority queue. If I have two SM's one configured with Sustained Downlink Data Rate of 6000 and the Low Priority Downlink CIR set to the default 0 and another SM with Sustained Downlink Data Rate of 6500 but with a High Priority channel enabled and High Priority Downlink CIR set to 500 and Low Priority Downlink CIR set to 6000 does the AP give priority to the SM with a setting in low priorty uplink/downlink over the SM with 0 in the CIR? Or is the only difference between the SM's at that point that one has a high priority 500 Kbit channel?

Last question: The high priority channel, is there a negative effect to provisioniong larger then needed high priority channels if they are not being fully used? IE: giving an SM that needs 90 Kbits for a VoIP call in DSCP 46 a high priority channel of 100 kbits vs 500 kbits. (Assuming they only use 90 kbits not that they use more then that)

Thanks for taking the time and keep up the good work. Many of changes in 13.4 seem very nice and feature improvements really help the argument for staying with Cambium equipment.

Tim


Hi Tim -

I'll answer your last 2 questions:

In this configuration, yes the AP will give priority to honoring the SM with the CIR configuration up to the configured CIR.   The order of precedence in the scheduler is as follows:

1)  High Priority (HP) CIR

2) Low Priority (LP) CIR

3) Multicast/Broadcast CIR

4) High Priority Data (beyond HP CIR)

5) Low Priority Data (beyond LP CIR)

6) Multicast/Broadcast data (beyond Mcast/Bcast CIR)

The CIR is honored on demand, but if the demand isn't there, then the scheduler moves onto the other priorities.  As far as device to device, it is a round robin scheduler.  

In your scenario, SM2 would be honored with 500 of HP CIR data, then 6000 of LP CIR data, and then, if there is room in the frame, SM1 would get its high priority data scheduled, then the SM2's remaining HP data, then SM1's LP data, then SM2's LP data.   Basically something to that effect.   The important thing to note is because you gave one SM an actual CIR, that will be attempted to be honored before getting to the SM without a CIR configured...  Hope that makes sense!

For your last question:

If the CIR is not filled, meaning there isn't enough data demanded, then the frame will be filled with other data following the priority flow I covered above.  The danger in over-provisioning CIR is that if there is the data demand there, and the scheduler can't honor all of the CIR, then it is a bit unpredictable as to what the data flows will be.  

Thank you for your feedback and questions!!

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@Timothy Alexander wrote:

Hello,

I have three questions:

First: The new frame utiliization statistics in 13.4 build 7 is it valid/accurate to use them as a rough guide to capacity/use on an AP. IE: If the downlink frame utilization is 80% it would be a good rough estimate it's roughly 80% used if the remaining customers/new customers meet the same average modulations/specs of the existing customers.  Up till now we've been determinening AP's capacity through the planning guide and a dart board (to guess average customer modulation per data bit).

...

Tim


Tim,

Thanks for the questions!

  • Regarding Frame Utilization: Yes, it is absolutely valid and accurate on PMP 450. And your understanding is correct, with the modulation level of the SMs being important. If you’re peaking out at 80% then you only have 20% left, if you have the same modulation level on the added throughput. If another SM comes in at a lower modulation level, it will fill up the frame faster than SM operating at high modulation rates.
    Note we provide 3 levels of monitoring and changing in in 13.4 (Build 9). 1 minute, 5 minutes and 15 minutes.

-Charlie

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