Vocera IP Phone Deployment in Cisco Unified Wireless Network Infrastructure Document ID: 71642 Introduction Prerequisites Requirements Components Used Conventions Executive Summary Vocera Badge Overview Vocera Call Capacity Considerations Vocera Communications Server Capacity The Vocera Solution Vocera's Infrastructure Planning Architecture Overview Multicast in an LWAPP Deployment Unicast−Multicast Delivery Method Multicast−Multicast Delivery Method Router and Switch Multicast Configuration Enable IP Multi
Audio Problems One−sided Audio Choppy or Robotic Audio Registration and Authentication Problems Appendix A AP and Antenna Placement Interference and Multipath Distortion Signal Attenuation NetPro Discussion Forums − Featured Conversations Related Information Introduction This document provides design considerations and deployment guidelines for the implementation of the Vocera® Badge Voice over WLAN (VoWLAN) technology on the Cisco Unified Wireless Network infrastructure.
Badge−to−Badge No special No special configuration No special configuration configuration Badge−to−Phone No special No special configuration No special configuration configuration Badge−to−Broadcast Badge Location Enable Controller Multicast Enable Controller Multicast Disable Vocera VLAN IGMP−Snooping or run 4.0.206.0 or later 4.0.206.
• Badge to Badge CommunicationsWhen one Vocera user calls another user, the badge first contacts the Vocera server, which looks up the IP address of the badge of the callee and contacts the badge user to ask the user if they can take a call. If the callee accepts the call, the Vocera server notifies the calling badge of the IP address of the callee badge to setup direct communication between the badges with no further server intervention. All communication with the Vocera server uses the G.
Multicast in an LWAPP Deployment Understanding multicast within an LWAPP deployment is necessary to deploy the Vocera broadcast function. This document later covers the essential steps to enable multicast within the controller−based solution.
Note: If AP Group VLANs are configured, and an IGMP join is sent from a client through the controller, it is placed on the default VLAN of the WLAN that the client is on. Therefore, the client might not receive this multicast traffic unless the client is a member of this default broadcast domain. Multicast−Multicast Delivery Method The multicast−multicast delivery method does not require the controller to replicate each multicast packet received.
Router and Switch Multicast Configuration This document is not a network multicast configuration guide. Refer to Configuring IP Multicast Routing for a complete implementation story. This document covers the basics to enable multicast within your network environment. Enable IP Multicast Routing IP multicast routing allows the Cisco IOS® software to forward multicast packets. The ip multicast−routing global configuration command is required to allow multicast to function in any multicast enabled network.
Disable Switch VLAN IGMP Snooping IGMP snooping allows a switched network with multicast enabled to limit traffic to those switchports that have users who want multicast to be seen while pruning the multicast packets from switchports that do not wish to see the multicast stream. In a Vocera deployment, it can be undesirable to enable CGMP or IGMP snooping on the upstream switchport to the controller with software releases earlier than 4.0.206.0.
Single Controller Deployment This is the most straight forward deployment scenario. It allows you to deploy the Vocera Badge solution with little deployment concerns. Your network must be enabled for IP multicast routing only to allow the access points to receive the LWAPP multicast packets. If required, you can limit network multicast complexity by configuring all routers and switches with the controllers multicast group.
Multiple Controller Layer 2 Deployment Multiple controllers must all have connectivity to each other via the same Layer 2 broadcast domain. Both controllers are configured for multicast as shown, using the identical access point multicast groups on each controller to limit fragmentation. With the assumption that this Layer 2 broadcast domain is connected via a common switch or a common set of switches, CGMP/IGMP snooping on these switches must be disabled for this single VLAN or run 4.0.206.
and has these packets routed through normal multicast routing methods. Figure 7Multiple Controller Layer 3 Deployment VoWLAN Deployments: Ciscos Reccommendations Wireless IP Telephony networks require careful RF planning. A thorough voice site survey is often required to determine the proper levels of wireless coverage and to identify sources of interference. Access point placement and antenna selection choices can be greatly eased with the help of the results of a valid voice site survey.
Inventory Various types of inventory can affect RF range, particularly those with high steel or water content. Some items to watch for include cardboard boxes, pet food, paint, petroleum products, engine parts, and so forth. Levels of Inventory Make sure you perform a site survey at peak inventory levels or at times of highest activity. A warehouse at a 50% stocking level has a very different RF footprint than the same warehouse at an inventory level of 100%.
• Hospitals can have several types of wireless networks installed. This includes 2.4 GHz non−802.11 equipment. This equipment can cause contention with other 2.4 GHz networks. • Wall−mounted diversity patch antennas and ceiling−mounted diversity omni−directional antennas are popular, but keep in mind that diversity is required. Warehouses Warehouses have large open areas that often contain high storage racks. Many times, these racks reach almost to the ceiling, where access points are typically placed.
(off−ACS) database to store the user names and passwords for the badges, Cisco does not recommend this practice. Because the ACS must be queried whenever the badge roams between access points, the unpredictable delay to access an off−ACS database could cause excessive delay and poor voice quality.
Switch Recommendations Note: If you use a Cisco Catalyst 4000 Series Switch as the main router in the network, ensure that it contains, at a minimum, either a Supervisor Engine 2+ (SUP2+) or Supervisor Engine 3 (SUP3) module. The SUP1 or SUP2 module can cause roaming delays, as can the Cisco Catalyst 2948G, 2980G, 2980G−A, 4912, and 2948G−GE−TX switches. You can create a switch port template for use when you configure any switch port for connection to an access point.
When Subnet Roaming is checked, it instructs the badge to request a new IP address after each roam. In the LWAPP environment, the infrastructure helps maintain client connectivity at Layer 3. When a voice client must wait for the DHCP server to respond before it is able to send or receive packets, delay and jitter are introduced. If Scan Default Channels (1,6,11) is not checked, the badge scans all 802.11b channels when the badge looks to roam. This prevents the forwarding of packets and seamless roaming.
access point is seen. Once this is complete and it is determined that adjusting this value is required, begin with a value of Ÿ1 dBm for the Transmit Power Control algorithm. Use this CLI parameter: config advanced 802.11b tx−power−thresh −71 Allow the network to work through this adjustment with a minimum of 30 minutes to an hour before you observe any changes. Once the network is given a sufficient amount of time, walk the site using the same survey tool and badges again.
Wireless Network Infrastructure Configuration The Cisco Unified Wireless Network design and deployment guide should be followed for the overall configuration of your WLC(s). This section provides additional recommendations specific to Vocera® Communication Badges. Note: Changes are left unsaved if you do not press the Apply button before you move to the next step. Complete these steps under the Controller top−level menu: 1. Change Ethernet Multicast Mode to Multicast. 2.
Figure 10List of WLC Interfaces Create the Vocera Voice Interface Complete these steps: 1. Click New. 2. Enter a tag name representative of your Vocera VoWLAN network in the Interface Name field. 3. Enter the VLAN number of that VoWLAN network in the VLAN ID field. 4. Click Apply and then click Edit in order to edit the interface that you just created. 5. Enter the IP addressing for this interface that is in the range of the VLAN and other related information. 6. Click Apply.
WLAN Configuration Complete these steps: 1. Update the Radio Policy field to a value that best fits you needs. 2. Change Admin Status to Enabled. 3. Set Session Timeout to 1800. 4. Set Quality of Service to Platinum. 5. Set Broadcast SSID to Enabled. 6. Set the Interface Name to the interface created for the Vocera Communication Badges. 7. Set the security options to match your corporate policies.
Configure Access Point Detail Complete these steps: 1. Click Detail. 2. Configure the AP Name. 3. Ensure that the access point is configured for DHCP. 4. Ensure that Admin Status is Enabled. 5. AP Mod should be set to local. 6. Enter the location of the access point. 7. Enter the controller name that the access point belongs to. The controller name can be found on the Monitor page. 8. Click Apply.
Configure the 802.11b/g Radio Complete these steps: 1. Click Wireless located at the top of the WLC and verify that all access points under Admin Status are set to Enable. Figure 14 2. Click Network (located near 802.11b/g). 3. Click AutoRF. 4. Use AutoRF to create a complete coverage with non−overlapping RF channel and a transmit power. In order to do this, select Automatic for both RF Channel Assignment and Tx Power Level Assignment.
5. Click Apply. 6. Click Save Configuration and see the Tune AutoRF for Your Environment section of this document. 7. Choose Wireless > Access Points > 802.11b/g Radios. Figure 16 Wireless IP Telephony Verification After you conduct an RF site survey and configure the access points and the phones, it is crucial to conduct verification tests to ensure that everything works as desired.
• The primary area of each access point cell (where the badges are most likely to connect to that particular access point). • Any location where there might be high call volume. • Locations where usage might be infrequent but coverage still has to be certified (for example, stairwells, restrooms, and so forth). • At the fringes of the access point's coverage area. • " These tests can be performed in parallel or series.
OR ♦ If the telephony server is available, initiate a call with a stationary device to the badge. ♦ Continually check voice quality while you traverse the total wireless coverage area. If the voice quality is insufficient, perform these tasks: ♦ Listen for all unacceptable changes in voice quality and take note of the location and radio values on your laptop and CQ values from the badge. ♦ Watch and listen for the badge to roam to the next access point.
Audio Problems There are a few common configuration errors that can cause some easily resolved audio issues. If possible, check audio problems against a stationary (reference) badge to help narrow the problem to a wireless issue.
• Re−authentication / Session TimeoutIf configured, a session timeout triggers a re−authentication which causes gaps in the voice stream (300 ms + WAN delay for 802.1x authentication). Appendix A AP and Antenna Placement This section gives examples of both proper and improper placement of access points (APs) and antennas. Figure 17 shows improper placement of an access point and antennas close to an I−beam, which creates distorted signal patterns.
Figure 20 shows the signal propagation caused by the wall on which the access point is mounted. Figure 20Signal Reflection Caused by a Wall The preceding examples also apply when you place access points and antennas in or near the ceiling in a standard Enterprise environment. If there are metal air ducts, elevator shafts, or other physical barriers that can cause signal reflection or multipath interference, Cisco highly recommends that you move the antennas away from those barriers.
Figure 22 shows a Cisco Aironet 5959 omni−directional diversity antenna properly mounted to a ceiling T−bar. In this case, the Cisco AP1200 is mounted above the ceiling tile. Figure 22Cisco Aironet 5959 Antenna Mounted to a Ceiling Figure 23 shows a Cisco AP1200 properly mounted to a wall. Figure 23Cisco AP1200 Mounted to a Wall Figure 24 shows the Cisco Aironet 2012 diversity patch antenna mounted to a wall. In this case, the Cisco AP1200 is mounted above the ceiling tile.
For areas where user traffic is high (such as office spaces, schools, retail stores, and hospitals), Cisco recommends that you place the access point out of sight and place unobtrusive antennas below the ceiling. Separation for non−diversity antennas should not exceed 18 inches. Interference and Multipath Distortion The throughput performance of the WLAN network is affected by unusable signals. WLAN interference can be generated by microwave ovens, 2.
While directional antennas can be of great value for certain indoor applications, the vast majority of indoor installations use omni−directional antennas. Directionality should be strictly determined by a correct and proper site survey. Whether you use an omni−directional or patch antenna, indoor environments require diversity antennas to mitigate multipath distortion. The Cisco Aironet Series Access Point radios allow for diversity support.
Related Information • Deploying Cisco 440X Series Wireless LAN Controllers • Solution Reference Network Design • Vocera Communications System Specifications • Technical Support & Documentation − Cisco Systems All contents are Copyright © 2006−2007 Cisco Systems, Inc. All rights reserved. Important Notices and Privacy Statement.
