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The need for QoS, configuration on Extreme Aerohive

Introduction

ΝΟΤ 
ENABlt ρος

This blogpost will focus on the configuration of QoS policies on Extreme Cloud IQ (Portal). Aiming to provide a real scenario which led to the implementation of QoS for an organisation. Before diving into this I cannot stress on the point that QoS solution will be successful only if it is implemented end to end. The QoS marking and policing if not honoured by the subsequent hops in the access <> distribution  <> core.

The Need for QoS

The issues arise when packets do not get prioritisation and are either dropped or queued. The network transmission quality is determined by latency, jitter and packet loss.  It becomes even more crucial with Wi-Fi being a shared and half-duplex medium it becomes all the more necessary to mark and prioritise the relevant traffic on the network. One may have 10Gbps internet or more but AP are often the bottlenecks in the network. With the adaptation of VoIP/Skype/Zoom and similar RTP/SIP applications, there is a need to make sure voice/video traffic get priority over other traffic. Moreover, Wireless networks and protocols are mostly designed for data services… so it is normally not possible “ just to drop” Rich Media on top and expect positive results.

Extreme Cloud IQ configuration

Let’s start with looking at the Extreme Cloud IQ configuration.

Classifier Maps

QoS Classifier Maps > Classifier map is used to mark traffic with Extreme Network QoS classes by various QoS classification systems (802.1p/DiffServ/802.11e).

Incoming Traffic – AP prioritises and forwards the incoming traffic as determined by the mapped QoS level.

Outgoing Traffic – AP uses marker maps.

If you login and navigate to below for checking the first option of “Classifier Maps”.

Configure > Network Policies >  Edit “Policy Name” > Additional Settings > QoS Options

ExtremeCIoud IQ Pilot 
Classifier Maps 
WIRELESS NETWORKS 
O 
O 
Network Policies 
POLICY DETAILS 
MANAGEMENT SERVER 
POLICY SETTINGS 
NETWORK SERVICES 
GOS OPTIONS 
Classifier Maps 
Marker Maps 
QoS Overview 
SECURITY 
DEVICE TEMPLATES 
Classifier Maps 
ROUTER SETTINGS 
ADDITIONAL SETTINGS 
DEPLOY POLICY 
Please note that Classifier Maps are only supported by IQ Engine devices and will not take effect on other devices. 
Classifier Maps 
Maps anonymous incoming traffic into the Extreme Networks 
classification system. Traffic classification can be performed based on 
following criteria. 
Re-use Classifier Maps Settings 
(Pick existing settings) 
Name • 
Description 
SERVICES 
Services 
LYNC 
LYNC AUDIO 
LYNC CONTROL 
SKYPE VOICE 
FACETIME 
MAC ouls 
Classifier-Map 
SSIDs 
802.1p/Diffserv/802.11e 
aos Class 
VOICE 
VOICE 
VOICE 
VOICE 
VIDEO 
Action 
PERMIT 
PERMIT 
PERMIT 
PERMIT 
PERMIT

The incoming traffic is mapped based on the network/application service defined in the classifier map. In the above screenshot you can see LYNC, LYNC AUDIO and others set as VOICE and action being PERMIT.

MAC OUIs and SSIDs

I haven’t used this in our config but one can choose to map traffic to classes based on either the source/destination MAC OUI in the packet or based on SSID

Add MAC OUI 
MAC OUI 
Gos Class 
Action 
Logging 
Apple-iPhone 
Background 
permit 
Enable
Add SSID 
SSID 
oos Class 
ssidO 
Voice

802.1p/DiffServ/802.11e

802.1p is a layer 2 prioritisation often described as Class of Service can be seen in the TCI field of the Ethernet frame. The 3 bits give 8 different classes as shown below. In my scenario I have used the DiffServ and 802.11e(WMM) for layer 3 QoS.

Name 
Description 
SERVICES 
56-63 
48-55 
40-47 
32-39 
00-07 
MAC OUIs 
Classifier-Map 
SSIDs 
802.1p/DiffServ/802.11e 
OFF 
802.1p 
7 
6 
5 
4 
3 
O 
2 
802.1p 
QoS Class 
Network Control 
Voice 
Video 
Controlled Load 
Excellent Effort 
Best Effort 1 
Best Effort 2 
Background 
ON 
DiffServ 
24-31 
16-23 
08-15 
DiffServ 
QoS Class 
Best Effort 1 
Network Control 
Voice 
Video 
Controlled Load 
Best Effort 1 
Excellent Effort 
Best Effort 2 
ON 
802.11e 
7 
6 
5 
4 
3 
O 
2 
802.11e 
QoS Class 
Network Control 
Voice 
Video 
Controlled Load 
Excellent Effort 
Best Effort 1 
Best Effort 2 
Background

DiffServ is concerned with classifying packets as they enter the local network. This classification then applies to Flow of traffic where a Flow is defined by 5 elements; Source IP address, Destination IP, Source port, Destination port and the transport protocol. The DSCP QoS  is retained end to end and one of the reason it is preferred more than 802.1p.

Before moving to 802.11e, let’s get basics correct.

802.11 use collision avoidance mechanisms unlike collision detection for Ethernet. The DCF (Distributed Coordinated Function) algorithm is used for media access. Regardless of any clients on the medium, a 802.11 WLAN device will wait for a DCF interframe space and then begin the transmission. Once the DIFS is counted down to 0, a random backoff timer is generated if the medium is not free.

Wait Until Medium is Free 
Count Down the DIFS & 
keep listening to medium 
Is the Medium Still Free? 
No 
Generate a random 
backoff value between 0 
and CWmin 
The DCF 
Decision Process 
Continually listen to 
medium to ensure it 
is quiet 
Yes 
Transmit the 
Frame 
Done 
Was an ACK 
received? (i.e. 
confirm there was 
no collision) 
Decrement the CW value to zero. 
If another station begins to 
transmit, defer until it is done, then 
wait another DIFS period before 
counting down the CW 
Double the previous 
cw. 
Choose 
a new random number between 
zero and the new CW, up to a 
maximum of CWmax

QoS is not possible with DCF alone and hence 802.11e was ratified. The EDCA (Enhanced Distributed Channel Access) included 4 queues(Background, Best Effort, Video, Voice), AIFS (ACs) and a range of contention windows (CWmin and CWmax). Two additional 802.11e enhancements included TxOP and Call Admission Control (CAC)

EDCA 1 WMM AC 
Legacy DCF 
Voice 
Video 
Best Effort 
Background 
AIFS Number 
DIES > 2 
2 
2 
3 
7 
CWmin 
15 
3 
7 
15 
15 
CWmax 
1023 
7 
15 
1023 
1023
QoS Classification and Marking: Mapping External Systems to Aerohive Classes 
56-63 
56 - 63 
48-55 
48 - 55 
40 - 47 
40 - 47 
32-39 
32 - 39 
24 • 31 
24-31 
16 - 23 
16 - 23 
8-15 
8-15 
For traffc traversing its wifi interfaces, the HiveAP 
maps Aerohive classes to IEEE 802. Ile tramc classes 
(defined in the wireless frame header) or to DSCP 
values (defined in the layer-3 packet header). 
For traffc traversing its Ethernet interface, the HiveAP 
maps Aerohive classes to 802.1 p traffic classes 
(defined in the layer-2 frame header) or to DSCP 
values (defined in the layer-3 packet header). 
Wireless 
Network 
802.11e Traffic Class 
7 
6 
5 
4 
3 
wifiO. 1 
DSCP Value 
Inbound Outbound 
56 
48 
32 
24 
16 
8 
ethO 
802.1p Traffic Class 
7 
6 
5 
4 
3 
2 
1 
Ethernet 
Network 
DSCP Value 
Inbound Outbound 
HiveAP 
erohive Clas 
7 
6 
5 
4 
3 
2 
2 
1 
802.11e 
Wire L2 
Header 
DSCP 
L3 
Header 
Default mappings of the Aerohive 
class system to standard OOS 
classification systems 
Data 
802.1p 
Wired L2 
Header 
DSCP 
Header 
56 
48 
40 
32 
24 
16 
8 
Data

Marker Maps

For outgoing traffic, one can define marker maps to map classes to priority numbers in standard classification systems (802.11e, 802.1p, and DiffServ). After defining classifier and marker maps, you then define classifier and marker profiles that enable one or more of the methods defined in the maps. Finally, you associate those profiles with SSIDs or interfaces to apply the mappings to traffic arriving at or exiting those interfaces.

Name * 
Description 
802.1p 
DiffServ 
QoS Class 
7 - Network Control 
6 - Voice 
5 - Video 
4 - Controlled Load 
3 - Excellent Effort 
2 - Best Effort 1 
1 - Best Effort 2 
O - Background 
DiffServ 
ON 
Marker-Map 
note: If both 802.1p and DiffServ are selected only DiffServ will take effect 
WMM Queue 
Voice 
Voice 
Video 
Video 
Best Effort 
Best Effort 
Background 
Background 
DiffServ Code Points 
48 
46 
34 
26 
18 
O 
10 
8

Verifying if WMM QoS is working

The QoS Data Frame includes the QoS Control field which provides the information in the Priority field.

Frame check sequence: øx412667cb [unverified] 
(FCS Status: Unverified] 
Qos control: øxeoø6 
0110 = TID: 6 
. .110 = Priority: Voice (Voice) 
. — QoS bit 4: Bits 8—15 of QoS Control field are TXOP Duration Requested 
. = Ack Policy: Normat Ack (øxø) 
. = Payload Type: MSDU 
= TXOP Duration Requested: e (no TXOP requested) 
CCMP pa rameters 
ccmp Ext. Initialization vector: øxøeeøøøee315F 
Key Index: ø 
Data (64 bytes) 
Data: 1968135a7bec2dfd1ø24aee916d562ac3d3ccd3f2d359f914978d8b2cf6872ed8ø6e39c8„. 
[Length: 64] 
IEEE 8ø2.11 Qos Data, Flags: .p.....TC 
Type/Subtype: Qos Data (øxoø28) 
Frame Control Field: ex8841 
. .øø = Version: 0 
eøøø eøøø 
løøø 
Flags: 
= Type: Data frame (2) 
= Subtype: 8 
øx41 
. ..øl = DS status: Frame from STA to DS via an AP (To DS: 
= More Fragments: This is the last fragment 
Retry: Frame is not being retransmitted 
= PWR MGT: STA witt stay up 
. = More Data: No data buffered 
. = Protected flag: Data is protected 
. = Order flag: Not strictly ordered 
1 From DS: e) 
(øxl) 
.øøø eøøø eø11 eeøø = Duration: 48 microseconds 
Receiver address: ExtremeN_3b: 81:54 3b:81: 54) 
Transmitter address: HuiZhouG_b7:2c:a3 (d4:ab: cd:b7:2c:a3) 
Destination address: WistronN_d3:3c:57 (44:e4:ee:d3:3c:57) 
Source address: HuiZhouG_b7:2c:a3 (d4:ab: 
BSS Id: 
STA address: HuiZhouG_b7:2c:a3 (d4:ab: :a3) 
Fragment number: ø 
. eeøø = 
1110 0110 eøll 
= Sequence number: 3683

Adding Custom Application for QoS Categorisation

Navigated to > Configure > Application > Add Custom

Helpful links for more reading

http://www.rhyshaden.com/qos.htm

https://techhub.hpe.com/eginfolib/networking/docs/switches/RA/15-18/5998-8155_ra-2620_atmg/content/ch04s04.html

https://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Mobility/vowlan/41dg/vowlan41dg-book/vowlan_ch2.html

https://docs.aerohive.com/330000/docs/help/english/ng/Content/gui/configuration/configuring-classifier-maps.htm

https://docs.microsoft.com/en-us/microsoftteams/qos-in-teams

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