Deployment Guide Best Practices Guide for Deploying SpectraLink e340, h340 and i640 Wireless Telephones October 2010 Version H
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones Table of Contents 1 2 3 4 5 6 7 Introduction........................................................................................................................ 3 1.1 1.2 1.3 SpectraLink e340/h340/i640 Wireless Telephones......................................................................3 SpectraLink Infrastructure .................................................................................
BEST PRACTICES GUIDE October 2010 1 Deploying SpectraLink e340, h340 and i640 Wireless Telephones Introduction Wi-Fi telephony, also known as Voice over Wireless LAN (VoWLAN), delivers the capabilities and functionality of the enterprise telephone system in a mobile handset. The Wi-Fi handset is a WLAN client device, sharing the same wireless network as laptops and PDAs.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones 1.3 VIEW Certification Program The VIEW Certification Program is a partner program designed to ensure interoperability and maximum performance for enterprise-grade Wi-Fi infrastructure products that support Polycom’s SpectraLink e340/h340/i640 and 8020/8030 Wireless Telephones and their OEM derivatives.
BEST PRACTICES GUIDE October 2010 2 Deploying SpectraLink e340, h340 and i640 Wireless Telephones Wireless LAN Layout Considerations SpectraLink handsets utilize a Wi-Fi network consisting of WLAN access points (APs) distributed throughout a building or campus. The required number and placement of APs in a given environment is driven by multiple factors, including intended coverage area, system capacity, access point type, power output, physical environment, and radio types. 2.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones to allow lower transmission rates in order to maximize coverage area. If a site requires configuring the APs to only negotiate at the higher rates, the layout of the WLAN must account for the reduced coverage and additional APs will be required to ensure seamless overlapping coverage.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones 2.1.2 Signal Strength To provide reliable service, wireless networks should be engineered to deliver adequate signal strength in all areas where the wireless telephones will be used. The required minimum signal strength for all SpectraLink handsets depends on the data rates enabled on the AP and may also require consideration for the 802.11 frequency band and modulation used.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones required levels will provide an adequate buffer for these propagation challenges, enabling a more reliable and consistent level of performance with low retry rates. 2.2 Access Point Configuration Considerations There are several fundamental access point configuration options that must be considered prior to performing a site survey and deploying a voice-capable WLAN infrastructure.
Deploying SpectraLink e340, h340 and i640 Wireless Telephones BEST PRACTICES GUIDE October 2010 2412 2417 2422 2427 2400 MHz 2432 2437 2442 2447 2452 2464 2483 MHz 10 5 9 4 8 3 7 2 1 2457 11 6 22 MHz Figure 3 - 802.11b Channels 2.2.2 AP Transmission Power and Capacity The AP transmit power should be set so that the handsets receive the required minimum signal strength, as defined in Section 2.1.2 of this document.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones Radio frequency spectrum analyzers can be used to help identify the sources of such interference. Once identified, interference is best mitigated by removing the interfering device(s) from the network area. Otherwise, it may be possible to change the channel setting of the interfering device to avoid conflict with the surrounding APs.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones signals and displays the signal strength along with the AP channel assignments. The site survey mode may be used to detect areas with poor coverage or interfering channels; check for rogue APs; confirm the Service Set Identification (SSID) and data rates of each AP and include the security and QoS mechanisms supported by the AP; and detect some AP configuration problems.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones Even with all of the known variables, there are many other vendor-specific characteristics associated with individual APs that make it difficult to quantify the precise number of concurrent calls per AP, without thorough testing of specific configurations.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones Note that traffic analysis is based on the aggregate traffic for all users, so users with higher or lower usage are included in these averages. The traffic engineering decisions are a tradeoff between additional call resources and an increased probability of call blocking. Call blocking is the failure of calls due to an insufficient number of call resources being available.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones can manage 16 wireless telephones total only eight can be in call at any one time. Therefore, heavy users should be spread across Telephony Gateways to reduce the chance of call blocking. 14 © 2010 Polycom, Inc. All rights reserved. POLYCOM®, the Polycom “Triangles” logo and the names and marks associated with Polycom’s products are trademarks and/or service marks of Polycom, Inc.
BEST PRACTICES GUIDE October 2010 3 Deploying SpectraLink e340, h340 and i640 Wireless Telephones Network Infrastructure Considerations 3.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones 3.2 Assigning IP Addresses SpectraLink handsets operate as LAN client devices and therefore require IP addresses to operate in the network. IP addresses can be assigned statically through the configuration menus on the handsets or dynamically using standard DHCP protocol.
BEST PRACTICES GUIDE October 2010 4 Deploying SpectraLink e340, h340 and i640 Wireless Telephones SpectraLink Voice Priority (SVP) Polycom pioneered VoWLAN for the enterprise and remains the market leader today. One key success factor has been our SpectraLink Voice Priority (SVP) mechanism for QoS. This method is proven to deliver enterprise-grade voice quality, battery life and call capacity for SpectraLink handsets.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones server failure, the wireless telephone system will be disrupted. To minimize downtime related to a failed master SVP Server or a single server, it is recommended that a spare SVP Server be readily available. The network administrator can assign the IP address of the failed unit to the replacement SVP Server.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones Figure 5 – Multiple SVP Servers Handset 1 registers with SVP Server 1 o Handset 1 always sends its packets to SVP 1 − SVP 1 forwards handset 1 packets to the call server or PBX − The call server or PBX sends packets from the telephone this handset is in-call with to SVP 1 − SVP 1 sends packets to the SVP managing the handset 1’s AP o When handset 1 is using AP A (associated with) it receives packets fr
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones 4.1.3.1 Scenario One Scenario One assumes that the handset has registered to SVP Server 1, associated to Access Point A, and managed by SVP Server 1 (Figure 6) Handset communicates only to SVP Server 1 in this case Figure 6 - Scenario One 4.1.3.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones handset are aware of all SVP Servers even if the Registration SVP Server identified by DHCP option 151 goes down, the handset will still find another SVP Server to use. This is the SVP self-healing concept in action. Any new or replacement wireless telephones may fail to Check-In if the SVP Server identified by DHCP option 151 is down.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones All DSCP values defined here, regardless of what values are used, must be configured for appropriate priority throughout the network to ensure end-to-end QoS functionality. It is critical that voice receive the highest priority to ensure the user experience is as good as possible. 22 © 2010 Polycom, Inc. All rights reserved.
BEST PRACTICES GUIDE October 2010 5 Deploying SpectraLink e340, h340 and i640 Wireless Telephones Security Proper security provisions are critical for any enterprise Wi-Fi network. Wireless technology does not provide any physical barrier from malicious attackers since radio waves penetrate walls and can be monitored and accessed from outside the facility. The extent of security measures used is typically proportional to the value of the information accessible on the network.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones 5.5 Firewalls and Traffic Filtering The traffic filtering capabilities of firewalls, Ethernet switches and wireless controllers can also be used as an additional security layer if configured to allow only certain types of traffic to pass onto specific areas of the LAN. To properly provide access control, it is necessary to understand the type of IP traffic used by the SpectraLink handsets.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones Figure 8 - Deploying SpectraLink Wireless Telephones with a VPN 5.7 Diagnostic Tools The SpectraLink handset provides three comprehensive diagnostic tools to assist the administrator in evaluating the functionality of the handsets and the surrounding wireless infrastructure. These tools are: Run Site Survey, Diagnostics Enabled, and Syslog Mode.
BEST PRACTICES GUIDE October 2010 6 Deploying SpectraLink e340, h340 and i640 Wireless Telephones Subnets, Network Performance and DHCP Subnets are used to create a boundary between network segments. Although these boundaries are logical, they become like a physical boundary for mobile network devices moving throughout the enterprise.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones configuration, regardless of what subnet the phone is operating in. This scenario requires fewer SVP Servers to be installed, but requires higher performance from the router (see performance requirements in Section 6.3) The ability to cross a subnet boundary exists in either scenario, but the SpectraLink handsets will need to be power cycled to obtain a new IP address within the new subnet.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones Figure 9 - Measuring Network Jitter In a multiple SVP Server configuration, jitter is measured from the SVP Server that is responsible for the traffic through a given AP to a wireless telephone. This may be different than the SVP Server that is acting as a proxy for the wireless telephone to the IP PBX. Refer to Section 4.1.3 for additional multiple SVP Server information.
BEST PRACTICES GUIDE October 2010 Deploying SpectraLink e340, h340 and i640 Wireless Telephones Gateway implementation the handset will also require DHCP options 151 and/or 152. Option 151 is specifically the IP address of the Registration SVP Server. Option 152 is for deployments that are running an OAI Gateway where the option field is populated with the IP address of the OAI Gateway. These options are only accepted as IP address by the handset.
BEST PRACTICES GUIDE October 2010 7 Deploying SpectraLink e340, h340 and i640 Wireless Telephones Conclusion The SpectraLink e340/h340/i640 Wireless Telephone uses Wi-Fi technology to deliver a full-featured mobile extension to a call server or PBX. The purpose of this document is to outline the network design criteria for a successful VoWLAN deployment.
