Deploying Microsoft Lync over Wi-Fi #AirheadsConf Italy

Deploying Lync over WiFi
John Turner, Bala Krishnamurthy
June 11-12

CONFIDENTIAL
© Copyright 2014. Aruba Networks, Inc.
All rights reserved
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Agenda
• Why UC and Wi-Fi?
• Challenges with Real Time Media & Wi-Fi
• Common Usage Scenarios
• Lync over Wi-Fi Multi-Tier Strategy
• Wi-Fi Deployment Guidance for Real Time Media
• Configuring QoS for Lync
• Lync SDN Program
• Q&A

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Why care about UC and Wi-Fi?
• UC is about a communication and collaborative
experience anywhere and on any device
• Wi-Fi by default, wired when necessary (in many
cases Wi-Fi only)
• Network managers tasked to plan for
(data/voice/video) Wi-Fi convergence
• Customers are pushing towards greater real time
media over mobile scenarios
• Wi-Fi has become a mainstream wireless
technology

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Challenges with Real Time Media &
Wi-Fi

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Real Time Media
• Streaming vs. Real Time Media
– Streaming applications like YouTube, Netflix, etc can utilize large
receive side buffers in order smooth out network delays
– Real Time Media is interactive and requires a high performance
network that can sustain continuous up/down stream traffic, with
low latency, jitter and packet loss
• Impact to Human Interaction
– Human communication starts to get negatively impacted with
latency of more than 250 msec (one way, mouth-to-ear latency)
– Bursty jitter or packet loss over a certain threshold cannot be
recovered, and leads to glitches in the audio and video stream
– Audio glitches are very disruptive and lead to a poor user
experience

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Real Time Media Network
Requirements
•
– Audio 50 Kbps to 220 Kbps per stream (incl. IP header and FEC overhead)
– Video 250 Kbps to 4 Mbps per stream
•
– Desired jitter less than 20 msec
•
– Desired less than 100 msec (one way)
– Acceptable less than 200 msec (one way)
– Depends on geography
•
– Desired 0%, acceptable <2% and not more than 3 consecutive lost packets
•
– Both UDP and TCP are supported for Lync 2013 Real Time Media
– UDP is preferred for Real Time Media as TCP recovery (retransmits) is usually too long to be useful

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Real Time Media Issues When
Running Over Wi-Fi
•
– Real Time Media has very different requirements when roaming between
APs then when stationary
– Delayed handovers from “sticky clients” can result in multi-second media
breaks for voice/video
– Clients often “stick” to an Access Point (AP) even when the signal strength
has deteriorated so far as to be unusable
– And at the opposite extreme, some clients may “ping-pong” rapidly between
multiple APs or SSIDs
•
– Background scanning mechanisms are off-channel too long and inconsistent
which may affect media traffic

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Real Time Media Issues When
Running Over Wi-Fi (cont.)
•
– Existing rate adaption algorithms not well suited for Real Time Media
– May take up too much airtime in retries when used for Real Time Media traffic
•
– Need a mechanism to prevent oversubscription of high priority traffic
– Optimizing available resources via load balancing, steering clients away from
congested APs, facilitating good roaming decisions, and avoiding low data rates are
preferable to denying new sessions (only used as a last resort)
•
– Data - SNR better than 25 db and RSSI better than -90 dBm
– Real Time Media - SNR better than 40 dB and RSSI better than -65 dBm

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Wi-Fi Deployment Guidance for
Real
Time Media

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Running Lync 2013 over Wi-Fi
• Data over Wi-Fi
• Devices - Desktops, laptop, slates, mobile smart phones
• Modalities - IM, presence, web conferencing, calendaring
• Real Time Media over Wi-Fi: Fixed
• Additional modalities (includes Lync Data over Wi-Fi) -
Voice mail, video conferencing, telephony, audio
conferencing
• Nomadic but stationary use of Lync services
• Real Time Media over Wi-Fi: Mobile
• Modalities same as with Lync Real Time Media over Wi-Fi
Fixed
• Originate, consume and terminate Lync services while on
the move

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Wi-Fi Deployment Guidance
Enterprise Infrastructure Recommendations
•
•
•
•
•
•
• Ability to classify and prioritize Lync traffic (SIP-TLS) in the presence of
lower priority data traffic
• Implement QoS throughout wired and wireless infrastructure to prioritize
voice and video
• Implement QoS/WMM with EF queue for WMM Voice
• Enable WMM on APs for QoS. Enable QoS on Lync servers and clients
•

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Enterprise Infrastructure Recommendations
•
• Deploy APs featuring dual (concurrent) 2.4 GHz and 5 GHz operation with 3x3
configuration and 1 Gbps backhaul
• 2.4 GHz band - drop 802.11b support, limit 802.11n support to 20 MHz channels
• 5 GHz band - if available, enable “RF band steering” to move dual-band client
devices to 5GHz RF, use 40 MHz channel
• Support for RF auto radio management of channel and signal strength
•
• Deploy applicable AP density for required coverage and capacity but keep signal
levels better than -65dBm and SNR better than 40dBm (association and roaming
probe responses should have SNR better than 25dBm)
• Deploy sufficient number of APs for seamless coverage
• Design for capacity based on # of clients in coverage area
• Plan for overlapping AP coverage (redundancy) as required
• In large conference rooms deploy multiple APs

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•
– Open space design is different from walled office designs
•
– Ubiquitous Wi-Fi coverage is required!
– Signal strength in coverage footprint (-65dBm or better)
–
– Baseline
• Spot Testing
• Walkthrough testing
• Roaming with Lync Client session calls
– Periodic surveys to ensure baseline performance remains consistent

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•
• BYOD is a reality so be prepared
•
•
• Manage NIC driver versions
• Note: When on battery power drivers tend to reduce Wi-Fi device power
•
•

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Configuring QoS for your Lync
deployment

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DiffServ QoS Model
Precede
nce
Level
DiffServ
Marking
ToS Name Description
7 DSCP 56
(CS7)
Network
Control
Reserved for IP routing
protocols
6 DSCP 48
(CS6)
Internetwork
Control
Reserved for IP routing
protocols
5 DSCP 40
(CS5)
CRITIC/ECP Express Forwarding
(EF)
4 DSCP 32
(CS4)
Flash Override Class 4
3 DSCP 24
(CS3)
Flash Class 3
2 DSCP 16
(CS2)
Immediate Class 2
1 DSCP 8
(CS1)
Priority Class 1
0 DSCP 0
(Default)
Routine Best Effort
Drop
Precedence
Class 1 Class 2 Class 3 Class 4
Low DSCP 10 (AF11) DSCP 18
(AF21)
DSCP 26
(AF31)
DSCP 34
(AF41)
Medium DSCP 12 (AF12) DSCP 20
(AF22)
DSCP 28
(AF32)
DSCP 36
(AF42)
High DSCP 14 (AF13) DSCP 22
(AF23)
DSCP 30
(AF33)
DSCP 38
(AF43)
Assured Forwarding
S
c
h
e
d
u
l
e
r
Dro
p
High
Dro
p
Med
Dro
p
Low
Drop Zone
Expedited Forwarding
DiffServ
Marking
Description
DSCP 46
(EF)
low delay, low loss and
low jitter

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Expedited Forwarding (EF)
Behavior
S
c
h
e
d
u
l
e
r
Drop
High
Drop
Med
Drop
Low
Drop Zone

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Expedited Forwarding (EF)
Behavior
S
c
h
e
d
u
l
e
r
Drop
High
Drop
Med
Drop
Low
Drop Zone
QoS engineering has to be managed consistently end-to-end,
or it can have a dramatic negative impact to all real-time voice and video traffic

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Todays IP Phone QoS Model
Marked by switch as
Best Effort (BE) for 802.1p
and DSCP
Marked by switch as
Expedited Forwarding
(EF) for 802.1p and DSCP
PSTN
IP Phone QoS is Secured

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Todays UC&C QoS Model
PSTN
Remark QoS for
Untrusted traffic to
Best Effort
One of the biggest issues for Lync is that Network
Elements are misconfigured for QoS and/or network
policies remark untrusted traffic to Best Effort
Result is poor Lync experience for voice and video

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Automated QoS and TE
UC / Application Admin
Time in Weeks
Ongoing
Monitoring &
Troubleshooting
Identify
traffic
classes
Configure
UDP ACLs
on
Switches
Inventory
WAN circuit
sizing
What
Codecs
?
Remark DSCP
for untrusted
applications?
Lock down
UDP port
ranges used
for voice/video
Identify
sites
Define
Erlang
traffic
models
Provision
CAC
across sites
Validate
SLAs
Ok, ready to
start rolling
out
Enable DSCP
…on all
endpoints
…
Network Admin
SDN will reduce cost of deploying QoS, Traffic Engineering
and Security for UC

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Lync QoS Recommended
Guidance

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Lync QoS Guidance
•
– Use same media ports across Lync server media roles for same modality type (e.g. audio)
– Use non-overlapping media ports across Lync server media roles for different modality types (e.g.
audio vs video)
– Make client audio/video port ranges subset of servers
• E.g. server audio port range = 49,152 – 57,500
• Client audio port range = 50,020 – 50,039
•
– Quality of Service Policy on Windows Vista/7/8 and Windows Server 2008 R2/2012
– QoS Packet Scheduler on Windows XP w/ controlled load (video, DSCP 34) and guaranteed
service type (audio, DSCP 46)
• Set-CsMediaConfiguration -EnableQoS $True
– Lync Phone Edition is using DSCP 40 for audio (change with Set-CsUCPhoneConfiguration -
VoiceDiffServTag 46)
– Lync for Mac 2011 is using CS5 (0x28) for audio and CS3 (0x18) for video
– Lync Mobile clients use hardcoded QoS Values

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Lync QoS Guidance
Config upstream QOS Policy for Lync desktop client
•
– In Group Policy Editor go to Computer Configuration -> Windows Settings -> Policy-based QoS
– Gpudate.exe /force
– On multi-adapter and/or Workgroup Mode computer set “Do not use NLA”=”1″ under
HKEY_LOCAL_MACHINESYSTEMCurrentControlSetservicesTcpipQoS
Client
Traffic
Type
DS
CP
Sour
ce IP
Destina
tion IP
Proto
cols
Source
port range
Destination
port range
Audio 46 Any Any TCP/
UDP
50020:5003
9
Any
Video 34 Any Any TCP/
UDP
58000:5801
9
Any
App
Sharing
24 Any Any TCP/
UDP
42000:4201
9
Any
File
Transfer
14 Any Any TCP/
UDP
42020:4203
9
Any

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Lync SDN Program

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Today’s UC&C challenges
• Network issues cause 60-80% of poor end-user
QoE
• Poor visibility into real-time traffic
– Lync uses encryption by default, making DPI difficult and
unreliable
– Skype tries to hide itself from networks
• Traffic engineering / QoS is complex & easily
broken
– Requires brute force static policies that must match
application server settings
– Intermittent problems are tedious to diagnose, especially for
Softphones and BYOD

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Why SDN
• Addresses increasing
complexity
• Realize operational
efficiencies
• Improves end-user
experience

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What is Application Driven SDN
Northbound Interface
Southbound Interface
SDN Application
• Logic and Network Service
Intelligence
Controller
Network Elements
• Physical or virtual
forwarding path
Applications Programing Networks

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“Network Service Application”
Driven SDN Model
Network
Element
Network
Element
Network
Element
Network
Element
Network
Element
Network
Element
Network
Element
SDN Controller Topology Inventory Flow Programming Statistics
Network Service
Application
Network Service Logic Policy
SDN Controller North-Bound Interfaces
Administrator Interface

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“End User Application” Driven
SDN Model
Network
Element
Network
Element
Network
Element
Network
Element
Network
Element
Network
Element
Network
Element
SDN Controller Topology Inventory Flow Programming Statistics
Network Service
Application
Network Service Logic Policy
SDN Controller North-Bound Interfaces
Administrator Interface
Abstraction
End User App
(Ex: UC)
Network Service
North-Bound Interface

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UC SDN Architecture

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UC SDN Dialog Event

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UC SDN Quality Update Event

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Basic Architecture and Flow (V2.0)

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Redundant Architecture and Flow
(V2.0)
ClientLync
Client
Lync FE + LDL
Lync FE + LDL
Primary
Lync SDN
Manager
Secondary
Lync SDN
Manager
Fault-tolerance, Pools and Fan-Out:
NMS/Network
ControllerNMS/Network
ControllerNetwork
Controller

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Redundant Architecture and Flow
(V2.0)
ClientLync
Client
Lync FE + LDL
Lync FE + LDL NMS/Network
Controller
Primary
Lync SDN
Manager
Secondary
Lync SDN
Manager
Fault-tolerance, Pools and Fan-Out:
NMS/Network
ControllerNetwork
Controller

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Initial Features Lync SDN API
V2.0
• Lync SDN Manager
• Basic filtering, aggregation, augmentation,
dispersion (stateful)
• No LDL changes. Backward compatibility
• Support for primary/secondary redundancy

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Architecture V2.1- Coming Out
Soon
LFE+
LDL
Lync
FE +
LDL Lync SDN
Manager
Lync SDN
Manager
Load-balancing, pools, state & configuration sharing:
FE +
LDL
Lync
FE +
LDL
Shared
State
Additional message type:
IncallQuality
Database or shared memory cache
NMS/Network
Controller
NMS/Network
ControllerNetwork
Controller

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Lync SDN API V2.1Features
• In-call Quality Updates
• Full load-balanced and redundancy pool
• State sharing using a database
• Simplified configuration and setup of LDL
• Internal re-organizing
• Move computation from LDL to SDN Manager
• Partner requests

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Where We Are Today
• Lync SDN API v2.0 Publically Available
• API can be installed on Lync 2010 and
Lync 2013
• LDL Must be installed on all FEs
– Continuing to advance the API with partner’s
requirements

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UC SDN Scenarios Being
Defined
• Automated Diagnostics:
– Pinpoint root-cause-analysis for degraded media calls
• Automating QoS
– Dynamically mark authorized voice and video traffic with the appropriate QoS markings.
• Dynamic Traffic Engineering of Bandwidth Capacity for each Class of Service:
– Dynamically adjust the amount of bandwidth associated with various Classes of Service (CoS) to match bandwidth requirements of the
corresponding applications.
• Call Admission control:
– Prevent voice and video traffic from exceeding the available bandwidth capacity, and notify applications of changes in available bandwidth
so they can adjust selected codecs (e.g. based on policies).
• Dynamic Traffic Engineering of Media Paths:
– Route media along a path that is best able to meet performance requirements (rather than along the “default” least-cost path).
• Security DDOS and IPS/IDS orchestration:
– Positive identification of authentic media flows to prevent scrubbing
• Firewall orchestration:
– Automating pinhole firewall provisioning of dynamic media flows
• Wi-Fi orchestration:
– Automating real-time-media flows over Wi-Fi for correct behaviors of STAs and APs for many scenarios

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Aruba SDN Overview
• Aruba Controller as the consumer of Lync SDN
messages
– PEF engine and roll based access
– Voice subsystem to collect WiFi statistics
– QOS to mark and prioritize
• SDN acts as a trigger
• Additional data from SDN adds correlated data
• Flow is unidirectional today

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Lync SDN – QoS Flow
1. User establishes Lync call to
another device
– Call setup is through Lync Front End
server, call is peer-to-peer
2. Lync server sends session
information to Controller via SDN
API to web services listener
3. Controller uses data for QoS and
AppRF visibility
– Voice Video Desktop Sharing DSCP
mappings are made in SSID profile
1
3
2

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Lync SDN – Collecting call data
1. At the end of each call,
participants send Quality of
Experience (QoE) data to the
QoE server, which is a
component of Lync
2. The QoE server reports stats
to the controller
3. Controller builds monitoring
pages
1
3
2

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Lync Components
Media for callback
SIP
https (XML)
Push notification
for Windows Phone
Media
gateway
Media server Front End server
Reverse
proxy
DMZ
WiFi
Internet
Lync push
notification
services
Edge
server
• AD
• DNS
• Exchange
• Front End server
• QOE server
• Reverse Proxy
• Edge Server

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Understanding Lync Bandwidth
Requirements
Lync bandwidth usage is variable but predictable
http://technet.microsoft.com/en-us/library/jj688118.aspx
Bandwidth Calculator Tool:
http://www.microsoft.com/en-us/download/details.aspx?id=19011
Codec Bandwidth
Voice Wideband Audio 91Kbps (MAX) / 39.8Kbps (Avg)
Video 1280x720 h.264 2510Kbps (MAX) / 460Kbps (Avg)
5 person video call (MAX) (5 x 2510) + (91 * 2) = 12.43Mbps
5 person video call (Avg) (5 x 460) + (39.8 * 2) = 2.32Mbps
This represents high end codec use, additional info at:

Deploying Microsoft Lync over Wi-Fi #AirheadsConf Italy

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