- In the On/Off list, select one of the following values:
- On: Allow these QoS settings to be used globally.
- Off: Disable Global QoS settings.
- In the Admission Control list, select one of the following values,
which specifies what happens to a QoS flow (for example, a newly established voice
call) that requests air resources that are not available at that time:
- Admit All: All QoS flows are allowed in the QoS traffic class,
even if the aggregate reserved bandwidth exceeds the available bandwidth.
This may result in a degradation of the entire QoS traffic class.
- Request Pending: If no bandwidth is available to reserve, the new QoS
flows are moved to the best-effort traffic class. When enough bandwidth
is released from other QoS flows, the flows that were placed in the best-effort
traffic class are upgraded to the QoS traffic class.
- Reject Request: If no bandwidth is available to reserve, requests for
resources are rejected and not the flows themselves. QoS flows are permanently moved to the best-effort traffic class. If additional bandwidth is available at
a later time, these QoS flows are not moved to the QoS traffic class.
By default, admission control is set to Request Pending.
- In the Drop Policy box, select one of the following values, which specifies
what happens to a QoS flow's packets when the queues for that flow are full:
- Head: New packets that
arrive after the queue has reached its maximum length are allowed in
the queue, and old information in the queue is replaced with the new
information. Select this option for applications that use constant-rate realtime
flows, such as voice applications, where minimizing delay is generally more important than
reducing packet loss.
- Tail: New packets that
arrive after the queue has reached its maximum length are dropped. Select
this option if you are using applications with built-in flow control.
- In the Default Time-to-Live box, type the amount of time that the system
recognizes and holds resources for an ongoing flow (for example, a voice call)
without seeing any packet activity.
The value can be between 0 to 65,535 seconds.
For example, if you set the default time-to-live value to 300 seconds,
a call can continue for 5 minutes without any packets being exchanged before
the resources for it are relinquished. Applications that use silence suppression
might require higher time-to-live values.
- In the UDP Time-to-Live box, type the amount of time the QoS UDP flow can be
inactive before the flow is moved to the best-effort class.
The value can be between 0 to 65,535 seconds.
- In the TCP Time-to-Live box, type the amount of time the QoS TCP flow can be
inactive before the flow is moved to the best-effort class.
The value can be between 0 to 65,535 seconds.
- Bandwidth scaling controls the overbooking factor for QoS flows.
A valid value is from 1% to 100,000%. Normally, this value is set to 100%. A value
under 100% reduces the amount of resources that can be reserved, allowing resources
for best-effort traffic in a fully loaded environment. Specify a value over 100%
when using applications that overestimate the amount of resources they use and is
best used to account for applications that use silence suppression
or vary the amount of traffic being sent. For example, if you specify a value of 110%,
the system acts as if there is 10% more real bandwidth available.
- In the Maximum Calls per AP box, enter the maximum number of simultaneous
calls for APs. Valid number of calls range from 0 to 256. By default, 0 is set, which allows
all calls. Specifying a call limit (threshold) per AP ensures a consistent level of voice
quality. This setting
implements the Call Admission Control (CAC) feature, which ensures a
consistent level of voice quality by setting a threshold for the number of
calls per AP. As an AP nears the set threshold, CAC denies new SIP connections
until enough bandwidth is available to effectively handle the resulting media
stream.
When the call limit for the AP is exceeded, all new calls receive a
486_BusyHere response until the number of calls is less than the specified
threshold. On handoff from one AP to another, if there are no resources
available in the second AP, the call is classified as Pending/Best-effort
until the needed resources are available.
- For Maximum Calls per Interference Region, you can indicate that a region
will stop adding phone calls when 0-256 calls are active.
- In the Maximum Stations per AP box, enter the maximum number of clients
(stations) that can associate with an AP. This value can be between 0 and 128;
by default, it is set to 128.
By setting this limit, you can configure client load balance across APs,
ensuring a level of QoS for client call sessions. When the maximum number of
stations per AP is reached, new call associations can be distributed among APs
and BSSIDs in a round-robin fashion, evening out the distribution if the Load
Balance Overflow setting is set to On.
- In the Maximum Stations per BSSID, enter the maximum number of clients
(stations) that can associate with a BSSID. This value can be between 0 and
1023; by default, it is set to 0.
By setting this limit, you can configure client load balancing across BSSIDs,
ensuring a level of QoS for client call sessions. When the maximum number of
stations per BSSID is reached, new call associations can be distributed among
BSSIDs in a round-robin fashion, evening out the distribution if the Load
Balance Overflow setting is on.
If you want to perform client load balancing across VirtualCells, then it
is recommended that you set this value to the number of devices in the network
divided by the number of VirtualCells (or BSSIDs). If you expect that at some
times there may be additional devices beyond that joining the network, you
should also set Load Balance Overflow to On so that once the
maximum number of stations limit is reached, round-robin will be performed to
balance new client assignments.
- In the Load Balance Overflow drop-down list, select On to enable
client load balancing across BSSIDs and APs, ensuring a level of QoS for
client call sessions.
This setting is used in conjunction with the Maximum Stations per AP and
Maximum Stations per BSSID settings. When this setting is enabled, and the
maximum number of stations is reached, new call associations are distributed
among APs and BSSIDs in a round-robin fashion, evening out the distribution.
- In the Maximum Calls Per BSSID, enter the maximum number of simultaneous
calls for BSSIDs. Valid number of calls range from 0 to 1023. By default, 0 is set, which allows
all calls.
By setting this limit, you can configure a threshold for the maximum number
of calls per BSS. This command implements the Call Admission Control (CAC)
feature, which ensures a consistent level of voice quality by setting a
threshold for the number of calls per BSS. As a BSS nears the set threshold,
CAC denies new SIP connections until enough bandwidth is available to
effectively handle the resulting media stream.
When the call limit for the BSS is exceeded, all new calls receive a
486_BusyHere response until the number of calls is under the specified
threshold.
- In the CAC Deauth drop-down list, select On to enable CAC (Call Admission
Control) resources. When set to On, the system sends an 802.11
De-authentication frame to push the client to an alternate BSS. When set to Off
(default setting), the system sends a modified INVITE message (with an URI of sip:#*#*#*#*#*@a.com)
to the SIP server so that it can generate a Reorder-Tone using the INFO
message. In all cases, if it is the terminator that exceeds the available CAC,
a 486_BusyHere message is sent to the SIP server.
- In the Station Assignment Age Time, enter a value for the amount of time an
AP caches a client's state while waiting for a Probe or Authenticate
request/response sequence with a BSS to complete. Possible values range from 5
to 2000; the default 30 seconds is adequate for most sites and should not be
changed unless recommended by Customer Service.
- In the SIP Idle Timeout, enter a value for the amount of time the a call can
idle before it must be answered (the setting is a part of CAC). The valid
range is from 5 to 3600 seconds, with the default setting at 120 seconds.
- To save your changes, click OK.