WLAN Design for Location, Voice & Video

transcript

WLAN Design for Location, Voice and Video

Ashutosh DashMarch 2014

2 #AirheadsConf

Agenda

• Mobility Centric Model• Design Guidelines for WiFi grade Voice

• Design Guidelines for WiFi grade Video

• Design Guidelines for WiFi grade Location

• QOS and Traffic Optimization

• Enterprise Diagnostics and Troubleshooting

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Mobility Centric

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Ongoing Shift to the Mobile Enterprise

Office-Centric Model

Employees

Corporate Devices

(PC, Phone and Printer)

Office Desk + Occasional VPN

Office Productivity Applications

Enterprise Applications

Perimeter Security

Mobility-Centric Model

Any User

(Employees, Partners, Customers)

Consumer Devices

(Tablets, Phones, Apple TV’s, Wireless printers etc.)

Anywhere, Anytime, Always Mobile

Mobile, Social, Cloud, Video

Data , Application and Network Security

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RF Design Guidelines for Voice & Video

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Pervasive RF Coverage

• 100% coverage in all areas of Voice use • Capacity based Wireless network design recommended

• Higher number APs operating with low TX Power• Small Cell sizes, clients use higher data rates

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ARM Features for Voice

• Interference Aware• Band Steering• Spectrum Load Balancing• Voice/Video Aware Scanning

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Clientmatch

• Deterministic steering of clients based on the SNR and signal level information gathered from client's perspective

• Steering decision is based on the probes request from the client

• Periodic load balancing• Resolves Sticky-client issue• Distributed client health monitoring• Single feature which makes cohesive decisions in mapping

clients to the best AP

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RF Design Best Practices for Voice

• Pervasive RF Coverage• Distance between APs to not exceed 50 Ft• Minimum RF signal (RSSI) levels of -65 dBm• Minimum signal-to-noise ratio (SNR) of 25 dB• Minimum and maximum AP power difference no greater than two

steps• Disable Lower data rates• In the Adaptive Radio Management™ (ARM) profile

• Enable voice/video/load aware scan• ClientMatch™-enabled

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RF Design Best Practices for Voice Contd ..

• Configure Supported Beacon rate to higher rate• Enable WMM Traffic Management

• Give higher of bandwidth to Voice and Video

• Enable Fair access• Provide high % of bandwidth to a VAP (For example, assign higher %

bandwidth to Corp VAP than Guest VAP)

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Best Practices for Video

• RF Best practices for Voice applies to Video as well• Best practices for Delivering multicast video

• Enable IGMP Snooping Or IGMP Proxy• Enable Dynamic Multicast Optimization (DMO)• Enable Decrypt-tunnel Dynamic Multicast Optimization (D-DMO)

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Designing a Roaming Network

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Designing a Roaming Network

• Difference in power levels on the deployed APs should not too high

• Set the local probe request threshold to 25

• Airtime fairness is recommended in an environment with mobile clients, this avoids slower clients taking too much airtime

• In a dot1x environment, enable EAPOL rate optimization

• For faster roaming use OKC and 802.11r

• Enable ClientMatch, ClientMatch will help with sticky client problem

• Match QoS markings that the devices are using

• Define two basic rates (avoid lower basic rates) . This gives the client flexibility and smoother roaming.

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Authentication/Encryption Guidelines

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Authentication/Encryption Guidelines

• 802.1x based authentication through radius server may introduce delay during re-association/roaming

• Use Opportunistic Key Caching with 802.1x for faster roaming• PSK works better for voice devices (less delay), but not a preferred

method due to weak security• EAP-TLS provides the best security and is preferred in enterprises than

EAP-PEAP

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End-to-End QoS

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QoS Segments

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Deep Dive into DSCP and WMM AC

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QOS - Tunnel Mode (WMM Only)

ArubaMobility Controller

Client-A, VO: DSCP 46

Client-B, VO: DSCP 46

DSCP 46WMM VI

DSCP 34WMM VI

DSCP 34

VO: 46VI: 34

Summary:• AP looks at L2 Priority and puts the DSCP as per DSCM-WMM mapping in controller• Controller decrypts the packet and uses L2 priority to assign DSCP mapping in

downstream direction

Controller decrypts the packet and retags as per L2 priority

AP looks at L2 priority and puts DSCP as per DSCP to WMM mapping

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QOS - DTunnel Mode (WMM Only)

DSCP 46WMM VI

DSCP 34WMM VI

DSCP 34

VO: 46VI: 34

Summary:• AP decrypts the packet and looks at L2 Priority to assign DSCP as per DSCM-WMM

mapping in controller• Controller passes the same DSCP tag in the downstream direction

Controller passes the same DSCP tag

AP decrypts the packet and retags as per L2 priority

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QOS - Tunnel Mode (Lync Heuristics for Voice)

DSCP 46WMM VI

DSCP 46WMM VO

DSCP 46

DSCP 34

VO: 46VI: 34

Summary:• AP looks at L2 Priority and puts the DSCP as per DSCM-WMM mapping in controller• Lync heuristics determines the AC based on the codec. If the codec used is voice, it gives

DSCP value corresponding to voice

Controller decrypts the packet and retags as per as per Traffic type

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QOS - Tunnel Mode (Lync SDN API for Voice)

DSCP 46WMM VI

DSCP 46WMM VO

DSCP 46

DSCP 34

VO: 46VI: 34

Summary:• AP looks at L2 Priority and puts the DSCP as per DSCP-WMM mapping in controller• Lync SDN API informs the controller that the call is a voice call. In this case, the DSCP

value assigned corresponds to the value for voice mapped under the ssid-profile. If there are multiple values, the first value will be assigned to the DSCP.

Controller learns the traffic type from Lync Server SDN API and does DSCP retagging

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Troubleshooting and Diagnostics

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Troubleshooting Guidelines

• Are RF and other Configuration Best Practices in place• Does your Network has End-to-End QoS• Can we isolate if it is an RF Network issue Or Wired Network• If required enable debugging at controller to get detail logs. For example,

if you are using Voice ALGs (Sip, Lync), enable following command to troubleshoot voice issues –(SE_PFE_1) (config) #logging level debugging user process stm subcat voice

(SE_PFE_1) (config) #show log user all

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RF heat map via Airwave

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Airwave – Client Troubleshooting

Thank You

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WLAN Design for Location, Voice & Video

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