Optimizing your client's wi fi experience

© 2017 Cisco and/or its affiliates. All rights reserved. 1
Optimizing Your Client’s
Wi-Fi Experience
Jan 30th 2018
Cisco
Connect
Calgary
Cisco Connect

© 2017 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
If you have delivered
wireless voice, with
seamless L3 roaming, in a
“all wireless environment”
with no control over your
clients….

AND HAVE NEVER HAD
A PROBLEM…

You may be interested in a more
more appropriate session….

Part 1: Optimizing Layer 2
Part 2: Optimizing Layer 1
Part 3: Innovations for Improved Client Experience
Part 4: What is possible in non Apple Environments?
Part 5: New Shiny Objects…
Agenda

Acknowledgement
• A large portion of this presentation was gleaned from the Cisco Live Berlin 2017 Session:
Wireless Deployment and Design for Media-Rich Mobile Applications
https://www.ciscolive.com/online/connect/sessionDetail.ww?SESSION_ID=93867&backBtn=true.
I highly recommend viewing it in it’s entirety and I thank my colleagues for allowing me to
use their content. Said session was created and delivered by the following Principal
Engineers:
• Robert Barton, P. Eng
• @MrRobbarto CCIE #6660, CCDE #2013::6
• Jerome Henry, Technical leader - TME
• @wirelessccie CCIE Wireless #24750, CWNE #45
• More related presentations and references will be noted in the supplemental information
slide(s) following the core material of this delivery.

Optimizing Layer 2
Part 1

VoIP Golden Rules for Wi-Fi
• Packet Error Rate (PER) <=1%
• As low jitter as possible, less than 100ms
• Retries should be < 20%
• End to end delay 150 – 200 ms, 30 ms in cell
• When these values are exceeded, MOS reduces too much
• Your mission is to keep MOS high
Success with voice = success with almost anything else
Part 1

But First,
The Fundamentals
Part 1

RF Design – Signal Power & Inverse Square Law
• Closer distance to the AP means higher signal level (RSSI), which translates to a more
complex modulation scheme and therefore higher data rate.
Surprisingly long distances can be achieved at low data rates
Part 1
Source: Wikipedia

RF Design – Two Handy & Related References
Source: mcsindex.com
AP datasheet (RX Sensitivity Section)
Part 1

Part 1
Source: mcsindex.com

Part 1

Higher Power Does not Always Mean Better Signal
You are a bit quiet
Blah blah blah
Is it better now?
now?
now?
now?
RSSI
dBm
Noise Level
Time
Aim for:
•Noise level ≤ -92 dBm
•RSSI ≥ 67 dBm
-> 25 dB or better SNR
•Typically, AP power same as client
power
-> commonly 11 to 14 dBm
Part 1

Imagine This Scenario . . . .
(based on an actual customer situation)
1
1
1
1
1
1
1
1
1
• Customer moved to first Wi-Fi
only building (including voice
and video)
• DISASTER! Wi-Fi was Terrible!!
• Investigation revealed all APs at
max power (power level 1)
• Covering ~7500 sq. ft. per AP
(2500 sq. ft. per AP is
recommended)
~ 120 ft
Part 1

SSIDs and Low Rates Consume Air Time
§ Reduce SSID number,
disable low
rates, solve L1 issues
§ Keep CU below 50%
§ Before: 8 SSIDs, all
rates allowed
§ After: 2 SSIDs, 802.11b
rates disabled
Assess Channel Utilization Often!
Part 1

What Should Your Minimum Rate Be?
§ Stop your cell where:
1. Signal to your clients is still strong
2. Clients and overhead traffic still “reasonably fast”
3. Retries are low
§ Beyond that point, clients should be able to get to another AP
if they want to.
§ On the right:
§ STA1 and STA2 hear each other -> less collisions
§ STA 1 and STA2 send @ 54 Mb/s -> short delays
§ STA3 is far from AP -> lower data rate (longer transmission delay),
higher PER and loss risks
§ STA3 does not hear STA1 and STA2 -> higher collision risk
24 Mbps
6 Mbps
STA1
STA2
STA3
Part 1

- 67 dBm… How Much is That in Data Rate?
§ At -67 dBm RSSI, SNR is
typically around 25 dB or more*
§ BER is important, because more
retries means more chances that
the frame will be dropped
§ Your job is to limit frame drops to
1% or less to maintain 4.1 MOS
§ You can run any rate of 24 Mbps
and up, and still have good
frame success rate
* well, at least in ideal conditions… see next slides
Part 1

Hand and Phone Position Affect Signal
Object in Signal Path
Signal Attenuation
Through Object
Plasterboard wall 3 dB
Glass wall with metal frame 6 dB
Cinderblock wall 4 dB
Office window 3 dB
Metal door 6 dB
Metal door in brick wall 12 dB
Phone and body position 3 - 6 dB
Phone near field absorption Up to 15 dB
There can be a 20 dB difference
between these photos
Part 2

§ Does it look broken
§ Neighbor relations
§ Channel assignments even
§ Physical layer issues
§ Roaming issues
§ Client Disconnects
§ Intermittent issues/no apparent pattern
§ Throughput/capacity issues
§ Load balancing issues
Quick and Easy Validation
How do you if KNOW if RRM is working fine?
If it had a proper foundation
It wouldn't be a tourist attraction
20Part 2

§ Everything – depends on Neighbor Relations
§ DCA channels –
§ TPC Power levels –
§ Coverage Hole Detection-
§ Optimized Roaming –
§ 802.11v, 802.11k –
§ CleanAir –
§ FRA
§ If Neighboring or NDP is broken – ALL of RRM’s output is Broken
§ What to check – Top to Bottom
Neighbors, Channel and Power – In that order
Does it Look Broken?
21Part 2

§ Display Channels on the
Floor Map –
§ Visually identify Adjacent
AP’s on same or
adjacent channels
§ Do the same with TX
Power, associated
clients, Channel
utilization
§ Useful information – In
Context
Get Context!
Prime Maps – A Great Place to Start
22Part 2

§ Select RX Neighbors
and point-
§ Neighbor relations
are displayed
§ Validate that Same
Channel AP’s are not
to RF Close
§ What’s Too Close?
§ That depends – but
greater than -72 is
usually
Prime Maps – A Great Place to Start
Selected
Chn 64
Selected
Chn 64 -79 dBm
Selected
Chn 64 -63 dBm
Selected
Chn 64 -77 dBm
*From Prime 3.2 – Next Generation Maps
23Part 2

§ Per Band (2.4 and 5 GHz)
§ TX Power Distribution of all
AP’s
§ Channel Distribution of all AP’s
§ RSSI Spread of all Clients
§ SNR Distribution of All Clients
When you need the needle to Jump from the Haystack!
WLCCA – WLC Config Analyzer
24Part 2

§ Is it Even-ish?
§ If It’s obviously lopsided –
then DCA may be stale
§ Why and What to do – a little
later
§ Look at Channels 120,124,
and 128
§ How many –B AP’s do they
have?
Channel Assignments –
Channel Distribution 2.4 Band:
Number of Radios on channel 1: 1399 (53.07%)
Channel Distribution 5.0 Band:
Number of Radios on channel 104: 11 (.37%)
25Part 2

§ Assuming TPC
§ Are the AP’s in the mid power
levels?
§ Or are they disproportionate
§ You can tell a lot about a
network by how TPC applies
power Dense/Thin
§ Remember TPC min/max and
RF Profiles….
TX Power Distribution
Power Level Distribution 5 Band:
Number of 5.0 Band Enabled Radios with Power Level 1: 1060 (35.84%)
Number of 5.0 Band Enabled Radios with Power Level 8: 8 (.27%)
Power Level Distribution 2.4 Band:
26Part 2

§ This is How the Network
Hears the Client
§ This tells us where the
network is in relation to the
clients
Client RSSI Distribution
WLCCA – WLC Config Analyzer –
Client RSSI Distribution 2.4
Band:
Number of Clients with RSSI -100: 9 (.14%)
Number of Clients with RSSI -92: 462 (7.08%)
27Part 2

Client SNR Distribution 5.0 Band:
Number of Clients with SNR 0: 106 (.90%)
Number of Clients with SNR 5: 349 (2.95%)
Client SNR Distribution 2.4 Band:
§ Client SNR is the Client RSSI –
at the AP, and the Noise – At
the AP!
§ SNR Determines the Data
Rate that can/will be used
§ 25 dB is a common design
goal
Client SNR Distribution
44% < 25 dB!
32% < 25 dB!
This tells you a LOT about how efficient a network can possibly be
28Part 2

Optimizing Layer 1
Part 2

Where do You Need Coverage?
§ Talk to end-users. Think what they will need and when, look for roaming paths
Bathroom?
Stairs?
Elevator?
Part 2

AP Placement Guidelines
§ Mount APs so that antennas are vertical (we use vertical polarization)
31Part 2

Radiation Pattern
§ Do not mount on a wall an AP built for ceiling
mount…
Part 2

AP Placement Guidelines
§ Avoid metallic objects that can affect the signal to your clients
Part 2

AP Placement – Bad Examples
§ AP too high:
• Low rate to the ground
• Client signal too weak at the AP level
> 20ft
Nice… but you won’t cover the
jet way as soon as the door closes
Part 2

AP Placement – Too Many, (4AP’s in <500sqft?)
Part 2

RF Design – Cell Overlap
• Cell overlap coverage is not always the only concern
• Roaming can fail if the client device does not have enough time to
properly scan for neighboring access points
• Imagine turning the corner around a metal or high attenuation barrier
– the RF environment changes very rapidly – no time for client to react
• Challenging RF obstacles need to be considered during AP placement
• A “Transition” AP that is placed at the intersection of hallways can
alleviate some scenarios
Part 2

RF Design – Next AP Position
• At point A the phone is connected to AP 1
• At point B the phone has AP 2 in the
neighbor list, AP 3 has not yet been scanned
due to the RF shadow caused by the elevator
bank
• At point C the phone needs to roam, but AP
2 is the only AP in the neighbor list
• The phone then needs to rescan and connect
to AP 3
1
3
2A B
C
Part 2

RF Design – Next AP Position
• At point A the phone is connected to AP 1
• At point B the phone has AP 2 in the
neighbor list as it was able to scan it while
moving down the hall
• At point C the phone needs to roam and
successfully selects AP 2
• The phone has sufficient time to scan for AP
3 ahead of time
A B
C
1
2
3
Part 2

Radiation Pattern and Its Impact on Roaming
§ When users are expected to roam while communicating, make sure their device can detect
neighboring APs BEFORE roaming…
AP signal drops fast
AP signal drops slowly
User does not have much space/time
to find the next AP
Part 2

Consider The Network Path Along The Way….
§ Design expected roaming paths and make sure all APs connect to the same controller, and overlap
allows for next AP discovery
Part 2

Going Further
• BRKEWN-2019 - 7 Ways to Fail as a Wireless Expert (2017 Berlin)
• https://www.ciscolive.com/online/connect/sessionDetail.ww?SESSION_ID=93858&backBtn=true
• BRKEWN-3010 - Improve enterprise WLAN spectrum quality with Cisco's advanced RF capacities
(RRM, CleanAir, ClientLink, etc) (2017 Berlin)
• https://www.ciscolive.com/online/connect/sessionDetail.ww?SESSION_ID=94062&tclass=popup
Part 2

Innovations for Improved Mobile
Quality Of Experience
Part 3

So Why Does Roaming Suck?
Part 3
All of this every time the device roams…
source: MY802.11.com

© 2017 Cisco and/or its affiliates. All rights reserved. Cisco Confidential© 2017 Cisco and/or its affiliates. All rights reserved. Cisco Confidential
What happens Today?
In 802.11, delay in roaming causes
poor experience, especially for
rich-media real-time applications.
Interoperability increases complexity
and prevents adoption.
Standards to the rescue?
• 802.11r – Fast Roaming
• 802.11k – Neighbor List
• 802.11v – BSS Transition
But
• Operational Complexity
• Multiple SSIDs – some clients can’t
associate with SSIDs enabled with 11r
Part 3

802.11k, 802.11v, 802.11r help efficient roaming
Fast Transition (802.11r)
802.11r enables fast roaming without complete reauth
802.11k sends you list of neighbors
802.11v BSS Transition sends you the new best AP: Cisco-AP-2Association
Cisco-AP-1 Cisco-AP-2 Part 3

802.11v & Radios On the Same AP
-51 dBm
46
Macro Cell
Micro Cell
Part 3

Association
802.11k, 802.11v, 802.11r help efficient roaming
Cisco-APNon-Cisco-AP
Legacy client cannot
join the same SSID
where 11r is enabled
I recognize that you
are an iOS device
11r is enabled for you
802.11k, 802.11v
are on by default
Legacy client that
does not support
11r/k/v can join the
same SSID
Part 3

Prioritizing
Business Apps
Part 3

What Happens
Today?
IT cannot prioritize business-critical
real-time traffic all the way from
clients to the destination
Today IT Administrators can classify
traffic ONLY at the access point. This
implies:
• Inability to prioritize between the client and
the AP
• Burden on IT administrator to manage the
applications across the enterprise
Part 3

Prioritizing Business Apps
Prioritize business critical apps and real time data
Turning on is easy
IT has control over which apps get priority
Part 3

Fast lane Configuration Profiles
A QoS configuration profile will ONLY be acted upon on a iOS 10, iOS 11,
macOS High Sierra or later device
Uses standard configuration profiling techniques (MDM, email, Web-based)
• The profile lists “whitelisted” applications in a dictionary file
• Whitelisted applications are allowed to mark QoS (DSCP/UP) upstream
• ‘Non-Whitelisted’ applications receive only BE/BK marking upstream
Used in Combination with Cisco and Apple mutual detection
Part 3

Fast lane only applies to Cisco and Apple
Deployments
Cisco-APNon-Cisco-AP
QoS Profile is
not considered
Applications
can only mark
UP, not DSCP*
QoS Profile or
no QoS Profile
Supports Fast lane
If a Profile was
received, All apps in
Whitelist Can mark
QoS upstream
QoS
Profile
* DSCP can be marked in some restricted conditions
Part 3

Fast lane enables network administrator to prioritize
applications per your environment
Cisco-AP
Supports
Fast lane
Admin can provision Apple iOS device and Mac computer
with a QoS profile*
Applications in whitelist get QoS marking
Other applications get BE/BK
Supports
Fast lane
Supports Fast laneSupports Fast lane
My profile for
this environment:
Minecraft = Real time
interactive
Viber = BE
My profile for
this environment:
Minecraft = BE
Viber = Voice
Cisco-AP*Without a profile, all applications are whitelisted by default in a FastLane cell
**FastLane does NOT override apps QoS, it either allow the app QoS or apply BE Part 3

Fast lane, Integrated
Meraki Systems Manager (Cisco’s Enterprise
Mobility Management solution) can whitelist
any app directly from the Apple App Store
Quality of service made simple
Fast lane Recap;
• Whitelisted applications get QoS
• Other applications are sent
as best effort or background
• QoS settings are added to a wireless profile
Part 3

Optimizing Wi-Fi
Connectivity
QoS Profile
Voice QoS Trust
AutoQoS
Better EDCA
Helps determine which applications
should receive QoS upstream
Trust upstream voice traffic, with
ACM and without TSPEC
Benefits IT Administrator
Configure optimal WLC QoS in
one click
Ease of Use
IEEE 802.11-2016 EDCA
Part 3

Benefits of App Prioritization
1
2
3
Business data gets priority and speed even if network is
congested
Reduces complexity - IT can focus on the business – the
network does the heavy lifting
Better reliability for business apps that demand a high quality of
service
Part 3

What About My Other Clients?
Part 4

Optimized Roaming
RX-SOP
Pervasive Wi-Fi
HDX Turbo
Performance
Event Driven
RRM
XOR Radio
FRA
Cisco CleanAir®
RF Profiles
RRM, DCA, TPC, CHDM
Load Balancing
Band Select
Client Link 4.0
Off-Channel
Scanning
Flex DFS
DBS
5GHz
Serving
2.4GHz
Serving
5/2.4GHz
Monitor
• Enabled by Dual 5GHz
• Adjust Radio Bands to Better Serve the
Environment
RF Optimized
Connectivity
Part 4

XOR Radio and FRA
2.4GHz
Serving
2.4-5GHz
Monitoring
5GHz.
Serving
5GHz.
Serving
2.4GHz
Serving
5GHz.
Serving
5GHz
Serving5Hz
Serving
2.4GHz
Serving
ü FRA-auto (default value) or Manual
ü Auto 2.4 -> 5GHz or Monitor Mode
ü Transition to 2.4 GHz if coverage drops
Part 4

Micro ßà Macro Cell Transitions
-51 dBm
-65 dBm
-51 dBm-51 dBm≥ 55
dBm?
Probe Response
Client Steering
• 802.11v BSS Transition – Default Enable
• 802.11k – Default Enable
• Probe Suppression – Default Disable
Client Types
• 11v capable – 802.11v BSS Transition
• Non-11v capable – 802.11k neighbor list +
disassociation
• No 11k or 11v support – Probe Suppression Micro – 5GHz on XOR
Macro -- Dedicated 5 GHz
Part 4

Better Support for Users on the Move
Optimized Roaming
Optimized Roaming: Wireless Devices
Connect to the Most Effective APClient Stickiness
Part 4

Better Client Connectivity
RXSOP, Load Balancing, Band Select
Part 4

Fine-tuning HDX with RF Profiles
Wi-Fi
Triggered ED-
RRM
Optimized
Roaming
RXSOP
Dynamic
Bandwidth
Selection
TPC, DCA
CHDM
FlexDFS
CORE:
• CleanAir
• ClientLink 4.0
• Turbo Performance
ü Pre-canned RF Profiles
ü Client Distribution
ü Data Rates
ü DCA, TPC, CHDM
ü Profile Threshold for
Traps
ü High Density Features
Part 4

Cisco Air Time Fairness (ATF)
After
Air time is allocated per SSID, per realm, per client.
There is now better control over how air time is shared.
Before
Rate limiting can only specify a bit rate (throughput) limit.
There is no way to limit the duration that the bit rate will use.
Time-
based
Automatic
calculation
on
availability
Ongoing
recalculation
Bandwidth
rate
unpredictable
Client-
dependent
fluctuation
Not time-
based
Improved Predictability and Performance
SSID 2
30%
SSID 1
70%
SSID 2
48%
SSID 1
52%
Part 4

& Last - Zero Impact Application Visibility and Control
Maintain performance with zero-impact AVC
Gain visibility
into the network
Control application
performance
App App App App
App App App App
App App App App
App App App App
Red Hat
Cisco
WebEx
Rhapsody Gmail
TIBCO
Microsoft
Exchange
YouTube Skype
SAP Citrix BitTorrent iTunes
SharePoint
Windows
Server
Google
Talk
Salesforce
Monitor critical
applications
Part 4

Fabric + Non Fabric
DNA Solution
Cisco Enterprise Portfolio
Automation
Assurance & Analytics ISE
Identity Services Engine
SDA +
non-SDA
Routers Switches Wireless WLC/AP
DNA Center
DESIGN PROVISION POLICY ASSURANCE
DNA Center:
Simple Workflows
Fabric +
Non-Fabric
Part 5

Wireless Sensors- Proactively assess performance
Test your network anywhere at any time
R1
Dedicated Sensor
AP1800
Flexible Radio Assignment
AP2800/3800
Sensors act as
clients
Access point
• On-Boarding Tests
• 802.11 Association
• 802.11 Authentication & Key Exchange
• IP Addressing DHCP (IPv4)
• Network tests
• DNS (IPv4)
• RADIUS (IPv4)
• First Hop Router/Default gateway (IPv4)
• Intranet Host
• External Host (IPv4)
• Application tests
• Email: POP3, IMAP, Outlook Web Access (IPv4)
• File Transfer: FTP (IPv4)
• Web: HTTP & HTTPS (IPv4)
1. Whole AP as a sensor: 1800, 2800, 3800
2. XOR radio as a sensor: 2800, 3800
3. Wall-mount dedicated sensor: AP1800
Flexible Radio Assignment Algorithm intelligently
identifies excessive radios and seamlessly converts
those into Sensor mode without client impact
Part 5Part 5

Wireless Sensors- Proactively assess performance
Test your network anywhere at any time
R1
Dedicated Sensor
AP1800
Flexible Radio Assignment
AP2800/3800
Sensors act as
clients
Access point
• On-Boarding Tests
• 802.11 Association
• 802.11 Authentication & Key Exchange
• IP Addressing DHCP (IPv4)
• Network tests
• DNS (IPv4)
• RADIUS (IPv4)
• First Hop Router/Default gateway (IPv4)
• Intranet Host
• External Host (IPv4)
• Application tests
• Email: POP3, IMAP, Outlook Web Access (IPv4)
• File Transfer: FTP (IPv4)
• Web: HTTP & HTTPS (IPv4)
1. Whole AP as a sensor: 1800, 2800, 3800
2. XOR radio as a sensor: 2800, 3800
3. Wall-mount dedicated sensor: AP1800
Flexible Radio Assignment Algorithm intelligently
identifies excessive radios and seamlessly converts
those into Sensor mode without client impact
Part 5

What Do Sensors Look Like?
Part 5

DNA Assurance – Wireless Insights Today…
Part 5

Assurance Across Your Network
Landing Page tells you what problems you need to solve now
Landing page tells you:
1. Overall health of your network,
clients and applications
2. Where the most serious
issues are happening
3. Your TOP 10 issues and
trends
Part 5

Single User Onboarding Troubleshooting
Part 5

Client View vs AP View
Step 1
• When choosing an AP, client scans (sends probe
requests, receives probe responses from each AP)
• Client then evaluates the answer (which AP is
best)
Step 2
• The client chooses an AP
• But the infrastructure does not know why this AP was
chosen, because the infrastructure does not know how the
client saw the network
Association
Part 5

Infrastructure Does not Know How the Client Sees
the Network
Why is this a problem?
Because without that view, the
infrastructure cannot help this (or other)
client find the “best AP” Association
Part 5

How do Cisco and Apple Solve this Issue?
Right after association, the iOS 11 device
sends a 802.11k beacon report:
Association
I scanned last 200 milliseconds ago
I saw:
BSSID SSID Channel Signal Protocol
bb:bb:cc:dd:ee:ff Blizzard 52 -72 dBm 802.11ac
cc:bb:cc:dd:ee:ff Blizzard 149 -86 dBm 802.11n
dd:bb:cc:dd:ee:ff Blizzard 153 -68 dBm 802.11ac
Part 5

How do We Use this Neighbor Map?
When a new client enters the cell, and asks
for a neighbor map, we can tailor the map to
this client location!
11k “what other APs around”?
Good neighbors for you to try:
Part 5

How do We Use this Neighbor Map?
When another client needs to roam, we can
suggest the best AP, seen from where the
client is!
11v “need to roam, where to go”?
Best AP for you:
Part 5

Client Goes Away
When a client roams or disconnects,
it sends a de-association message Am out of here
But the AP does not always know why… bad
signal? Something else?
Part 5

Client Goes Away
Why is this a problem?
Am out of here
Without knowing why a client is gone, we
cannot help other clients in the same location
(is this location okay? Is there a better AP
there? Is there incompatibility in config at this
location? And so many other questions…)
Part 5

How do Cisco and Apple Solve this Issue?
When a client roams or disconnects, it sends
a de-association message Am out of here… because the user shuts me down
And it adds a proprietary reason code
Part 5

How do We Use this Information?
By knowing why a client leaves, we can:
Help that client if there is a parameter
mismatch
Help other clients in the same location if
there is an RF issue
Collect data to understand patterns (where
clients go, etc)
Am out of here… because I am losing signal
Part 5

Knowing your Client
After association, the iOS 11 client also
provides important information
Seen RSSI for all nearby radios
Device Model Info
Neighbor AP Info
I am iOS 11.0, iPhone 7 plus
Association
Part 5

Client Details
Previous
Disconnect
The Client’s view of
APs
For the First Time Ever, Know How Your iPhone or
iPad ”Sees” the Wireless Network
Neighboring
AP’s
Part 5

Screenshot of the Apple Analytics
Part 5

Platforms To Support Analytics on DNA-C 1.1
Part 5

Thanks…

Optimizing your client's wi fi experience

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