Related Manuals for SpectraLink NetLink Wireless Telephones Best Practices White Paper Wireless Telephone
Summary of Contents for SpectraLink NetLink Wireless Telephones Best Practices White Paper Wireless Telephone
- Page 1 Deploying NetLink Wireless Telephones Best Practices White Paper Version 1.0 May 2004...
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Page 2: Wireless Lan Layout Considerations
SpectraLink pioneered the use of Wi-Fi telephones in a wide variety of applications and environments, making SpectraLink’s NetLink Wireless Telephones the market-leading Wi-Fi telephone devices. This document identifies issues and solutions based on SpectraLink’s extensive... - Page 3 Coverage One of the most critical issues in deploying NetLink Wireless Telephones is ensuring sufficient wireless coverage. Often enterprise Wi-Fi networks are designed only for data applications and may not provide adequate coverage for wireless telephone users. Quite often these networks are designed to cover only areas where data terminals will be used, and do not include coverage in other areas such as stairwells, bathrooms, building entrances, or lobby areas where NetLink handsets may be used.
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Page 4: Power Considerations
LANs. Such devices generally create bottlenecks for network capacity and add delay to the overall network, which is not tolerable in the boundaries of QoS requirements. SpectraLink does not support a configuration that includes wireless bridges and does not recommend using wireless bridges within any wireless voice network. - Page 5 In addition, all APs must be set to operate at the same power output. SpectraLink highly recommends a power output setting of 100 mW. If this cannot be accommodated, SpectraLink recommends a 50 mW setting and requires a minimum of 30 mW. With lower power output settings, special attention must be made to AP placement to ensure there are no frequency re-use issues.
- Page 6 Capacity The network capacity requirements also factor into the number of APs required, although in most cases the coverage area is the primary factor. Data traffic is very bursty and sporadic, but data applications can tolerate network congestion with reduced throughput and slower response times. On the other hand, voice traffic cannot tolerate unpredictable delays, but at least the bandwidth requirements are constant and consistent for every phone call.
- Page 7 Wireless Telephones using this codec on various APs has not been well tested. To allow for bandwidth to be available for data traffic, SpectraLink provides the ability to limit the number of calls per access point within the NetLink Telephony Gateway and SVP Server. The “Calls per Access Point”...
- Page 8 2.3.2 Push-to-Talk The push-to-talk (PTT) mode of the NetLink i640 Wireless Telephone uses SpectraLink’s proprietary SpectraLink Radio Protocol (SRP) Multicasting ADPCM encoding. If a PTT broadcast is active (i.e. a user presses the Considerations PTT button), the feature will use the bandwidth as indicated in the table above for the single transmitting i640 Wireless Telephone and one half of the bandwidth for all of the receiving i640 Wireless Telephones.
- Page 9 User Calling Intensity Erlangs per User Max Active Calls per AP Users Supported per Access Point Areas where more Wireless Telephone usage is expected, such as cafeterias and auditoriums, can be provided with additional capacity to support more users by installing addition APs with smaller coverage areas.
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Page 10: Network Infrastructure Considerations
Network Infrastructure Considerations Physical The NetLink Wireless Telephone infrastructure components should connect to the facility’s local area network (LAN) using Ethernet Connections switches, as opposed to Ethernet hubs, to provide adequate bandwidth and limit traffic collisions. Ethernet switches should be configured to negotiate the connection requirements automatically. - Page 11 White Paper Gateways, a separate TFTP server must be provided. Also, the NetLink SVP Server requires a separate TFTP server for software updates. The NetLink Telephony Gateway cannot be used as a TFTP server for the NetLink SVP Server code. NetLink Telephony Gateways receive software updates only through an FTP server.
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Page 12: Quality Of Service
Packet filtering requires recognizing the packet’s protocol identifier, which for SpectraLink packets is registered protocol ID 119 for the SpectraLink Radio Protocol (SRP). The NetLink SVP Server also performs packet delivery timing in the link to the Wireless Telephones that is critical for ensuring seamless handoffs among APs and for enhanced battery management processes. - Page 13 White Paper data transmission rate of 2 Mb/s. A NetLink SVP Server is required for applications using an IP telephony server or using more than four NetLink Telephony Gateways. A NetLink SVP Server can also be used with four or fewer NetLink Telephony Gateways to allow a maximum data transmission rate of 11 Mb/s.
- Page 14 To address the voice quality issues with most security mechanisms, SpectraLink and Cisco have worked together to deliver a Fast Secure Roaming (FSR) mechanism. FSR allows the authentication process to be done in a way that minimizes the number of messages required between the NetLink Wireless Telephones and the Cisco wireless LAN infrastructure.
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Page 15: Mac Filtering
Wi-Fi Alliance is Wireless Protected Access (WPA), which is a subset of the 802.11i standard. SpectraLink is committed to industry standards and will implement the 802.11i security standard once it is ratified. Depending on the required components of this standard, an enhanced security method that is conducive to mobile voice requirements, like the Cisco FSR mechanism, may be required to provide the best voice quality. - Page 16 NetLink SVP Server use TCP and UDP and other common IP protocols from time to time. These include DHCP, DNS, WINS, TFTP, FTP, Telnet, ARP, and ICMP. SpectraLink uses proprietary UDP channels between the infrastructure components that use UDP ports 5454 - 5458.
- Page 17 Virtual Private Virtual Private Networks are secured private network connections. VPNs typically employ some combination of encryption, digital Networks certificates, strong user authentication and access control to provide (VPNs) security to the traffic they carry. They usually provide connectivity to many devices behind a VPN concentrator.
- Page 18 NetLink Wireless Telephones must reside within the same subnet as the source of the SpectraLink Voice Priority (SVP) control. SVP can be controlled from a NetLink Telephony Gateway, a NetLink SVP Server, or a combination of the two.
- Page 19 With a little background study, both network and telephony professionals will be able to easily and confidently design and deploy a SpectraLink Wi-Fi telephony solution. Page 18 White Paper...
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