# Question regarding Radio statistics - outdiscards

**URL:** <https://community.cambiumnetworks.com/t/question-regarding-radio-statistics-outdiscards/56085>\
**Category:** PMP\
**Created:** [May 8, 2018, 8:26pm UTC](https://community.cambiumnetworks.com/t/question-regarding-radio-statistics-outdiscards/56085 "2018-05-08T20:26:38Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![rnelson](https://d10gw3vjmzyp8.cloudfront.net/letter_avatar_proxy/v4/letter/r/65b543/32.png) [@rnelson](https://community.cambiumnetworks.com/u/rnelson)\
**Post date:** [May 8, 2018, 8:26pm UTC](https://community.cambiumnetworks.com/t/question-regarding-radio-statistics-outdiscards/56085/1 "2018-05-08T20:26:38Z")

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We are seeing some outdiscards on the AP radios (Statistics-\>Radio tab) and had a few questions regarding this statistic.

The 450 user guide has this definition for outdiscards:

```
outdiscards Count: This field displays how many outbound packets were discarded without
                   errors that would have prevented their transmission. (Some of these
                   packets may have been discarded to increase buffer space.) 
```

That definition is quite vague for the purpose of figuring out what is causing the discards.&nbsp;

What is the algorithm for determining what increments the outdiscards count?&nbsp; What is an acceptable discard rate over time for the radio transmitting to SMs?&nbsp; Are there any tweaks/parameters/settings we can look at to reduce these discards?

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**Author:** ![CambiumMatt](https://d10gw3vjmzyp8.cloudfront.net/user_avatar/community.cambiumnetworks.com/cambiummatt/32/19821_2.png) [@CambiumMatt](https://community.cambiumnetworks.com/u/CambiumMatt)\
**Post date:** [May 9, 2018, 3:20pm UTC](https://community.cambiumnetworks.com/t/question-regarding-radio-statistics-outdiscards/56085/2 "2018-05-09T15:20:08Z")

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The statistic itself is there to measure the discarded packets.&nbsp; I have asked engineering to respond to this with possible reasons&nbsp;_why_ this stat would be incremented...

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**Author:** ![Charlie](https://d10gw3vjmzyp8.cloudfront.net/user_avatar/community.cambiumnetworks.com/charlie/32/11598_2.png) [@Charlie](https://community.cambiumnetworks.com/u/Charlie)\
**Post date:** [May 9, 2018, 3:51pm UTC](https://community.cambiumnetworks.com/t/question-regarding-radio-statistics-outdiscards/56085/3 "2018-05-09T15:51:48Z")

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> * * *
> [@rnelson](https://community.cambiumnetworks.com/u/rnelson/summary)wrote:  
> 
> We are seeing some outdiscards on the AP radios (Statistics-\>Radio tab) and had a few questions regarding this statistic.
> 
> The 450 user guide has this definition for outdiscards:
> 
> ```
> outdiscards Count: This field displays how many outbound packets were discarded without
> errors that would have prevented their transmission. (Some of these
> packets may have been discarded to increase buffer space.) 
> ```
> 
> That definition is quite vague for the purpose of figuring out what is causing the discards.&nbsp;
> 
> What is the algorithm for determining what increments the outdiscards count?&nbsp; What is an acceptable discard rate over time for the radio transmitting to SMs?&nbsp; Are there any tweaks/parameters/settings we can look at to reduce these discards?
> 
> * * *

rnelson,

RF Out Discards happen when the VC's queue is backed up and is dropping the packet. This can be caused for a few reasons:  
1) A very fast burst of packets on one VC can fill up the queue. This is most commonly seen on some uplink Video Surveillance&nbsp;equipment that sends a huge burst of data but only once a second. To address this there is an option "Configuration -\> Radio -\> Large VC data Q". However, in general too much queueing is not beneficial for TCP, so generally not recommend to have this option for a typical&nbsp;SM.  
  
2) The more common problem is the RF is generally full. This can be seen from Statistics -\> Frame Utilization. When this is at 100% then the RF is maxed out and will be dropping packets and pegging this stat. I don't have a good answer for an acceptable rate, as it depends upon your model and over subscription. Perhaps other providers can chime in on their experience. In general it's not a terrible thing as TCP traffic will be retransmitted. So this is normal stat that is expected during busy RF periods.  
To&nbsp;increase the RF pipe&nbsp;can be done in lots of ways and here's a few:

- Larger Channel Bandwidth (of course not always possible)
- Increasing modulation of traffic (like adding dish or moving to cleaner channel)
- Adjusting downlink/uplink ratio (if only one of the directions is full, but of course careful to do this for whole sector)
- Moving SMs to other APs
- Decreasing the Sustained Data Rate of SMs using all the bandwidth, so that the RF has more room for other users.
- If SMs have RF out discards, maybe increasing the number of Contention Slots will help the SM get Bandwidth Requests up to the AP so it can be scheduled. This is a tough one to say in general, but we are planning an Auto Contention feature to optimize this automatically.

Even if not seeing high Frame Utilization for a 1 minute&nbsp;period, it's possible for a portion of that it had several full frames in a row, backing up the RF.
