VoIP (Voice over IP) CoS queuing on Dell Networking N-Series switches A deployment guide for Dell Networking switches

Transcription

1 SION DR draft VoIP (Voice over IP) CoS queuing on Dell Networking N-Series switches A deployment guide for Dell Networking switches Dell Engineering May 2014 A Dell Deployment and Configuration Guide

2 Revisions Date Description Authors May 2014 Version 1.0 Victor Teeter PAPER IS FOR INFORMATIONAL PURPOSES ONLY, AND MAY CONTAIN TYPOGRAPHICAL ERRORS AND TECHNICAL INACCURACIES. THE CONTENT IS PROVIDED AS IS, WITHOUT EXPRESS OR IMPLIED WARRANTIES OF ANY KIND Dell Inc. All rights reserved. Reproduction of this material in any manner whatsoever without the express written permission of Dell Inc. is strictly forbidden. For more information, contact Dell. PRODUCT WARRANTIES APPLICABLE TO THE DELL PRODUCTS DESCRIBED IN THIS DOCUMENT MAY BE FOUND AT: Performance of network reference architectures discussed in this document may vary with differing deployment conditions, network loads, and the like. Third party products may be included in reference architectures for the convenience of the reader. Inclusion of such third party products does not necessarily constitute Dell s recommendation of those products. Please consult your Dell representative for additional information. Trademarks used in this text: Dell, the Dell logo, PowerConnect, OpenManage, EqualLogic, Compellent, and Force10 are trademarks of Dell Inc. Other Dell trademarks may be used in this document. Cisco Nexus, Cisco MDS, Cisco NX-0S, and other Cisco Catalyst are registered trademarks of Cisco System Inc. Microsoft, Windows, Windows Server, Internet Explorer, MS-DOS, Windows Vista and Active Directory are either trademarks or registered trademarks of Microsoft Corporation in the United States and/or other countries. Broadcom and NetXtreme are registered trademarks of Broadcom Corporation. Qlogic is a registered trademark of QLogic Corporation. Other trademarks and trade names may be used in this document to refer to either the entities claiming the marks and/or names or their products and are the property of their respective owners. Dell disclaims proprietary interest in the marks and names of others. 2 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

3 Contents 1 Introduction High Availability and QoS VoIP Example Configuring the Dell Networking N Configuring the Dell Networking N Configuring the 3CX PBX Configuring VoIP phones Connecting PCs to Phones Troubleshooting Tips Problem Isolation Show Commands Interference of other Applications VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

4 Executive Summary Voice over IP (VoIP) traffic on Ethernet networks is time-sensitive due to the need for IP phone users to connect through these networks in real-time, without delays in the transmission or reception of audio packets. It is just as important that conversations are clear and distinct, without variations in volume, or unwelcome noise. Dell Networking N-Series switches provide features that ensure VoIP traffic is delivered with high quality and in a timely manner, thus providing exceptional phone service to the user. To avoid issues of slow or delayed voice transmission, voice traffic can be separated and be given priority over other data coming into the port. The voice VLAN feature also ensures sound quality is maintained even when data traffic is congested. When multiple devices are connected to the same switch port (i.e. an IP phone and a PC), the port uses one VLAN for voice and a separate VLAN for data. This paper provides instructions on deploying a successful VoIP network and presents an example using common IP phones available in today s market. 4 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

5 1 Introduction This document is designed as a supplement to the Dell N-Series User Guide and provides easy step-bystep instructions to help users set up and configure Dell N-Series switches to use VoIP and work seamlessly with other VoIP software and devices at the access layer. Dell Networking N3000 and N4000 switches are used in the VoIP examples in this document. However, any of the N-Series switches listed below will accept the commands in this paper when configuring VoIP. N2024 N3024 N4032 N2024P N3024P N4032F N2048 N3024F N4064 N2048P N3048 N4064F N3048P Figure 1 shows the overall network topology that is presented in this guide. The 3CX PBX (Private Branch Exchange) server shown in the figure is a PBX/SIP (Session Initiation Protocol) phone system for standard SIP software and hardware phones. A free version of the software is used to demonstrate the example configurations in this guide. Other call management servers will work as well. Note: The 3CX VoIP Phone System for Windows (free version) can be downloaded here: 5 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

6 PowerEdge COMBO P 23 10GBASE-T MODULE 1 2 Stack No. 1 SFP COMBO P 23 10GBASE-T MODULE 1 2 Stack No. 1 SFP MLAG Peer Link Dell Networking N4064F Dell Networking N4064F Dell Networking N3024P Dell Networking N3024P 3CX PBX Server DHCP Server SNOM (VLAN 100) Polycom (VLAN 100) Polycom (VLAN 100) Polycom (VLAN 100) SNOM (VLAN 100) VLAN 100 VLAN 100 = Voice VLAN 200 = Data. VLAN 200 VLAN 200 VLAN 200 Figure 1 VoIP Example Topology 6 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

7 2 High Availability and QoS To provide added resiliency, integrity, and quality to voice and data traffic combined on a network, there are a few measures that can be taken such as creating an MLAG (Multi-Switch Link Aggregation Group) topology on the network and setting the QoS (Quality of Service) to categorize and prioritize traffic types. Both of these features are discussed below and are included in the example configuration in the next section. High Availability Adding MLAG to the network will provide failover in case of a single cable or switch failure. Section Configuring the Dell Networking N4000 below provides instructions on setting up two N4000 switches in an MLAG domain in order to deliver high availability VoIP on the network. MLAG domain MLAG peer Peer-Link MLAG peer MLAG Partner Switch MLAG domain appears as a single logical switch to all partner switches on the network Figure 2 MLAG Figure 2 shows how an MLAG domain can be connected to a single partner switch which can be used to connect IP phones, PBX servers, and any other hosts and servers. Additional partner switches can be connected to the MLAG domain in the same way. Servers and hosts can then be connected to each of the partner switches to communicate through the MLAG domain. The example provided below gives the configuration for an MLAG domain and multiple partner switches. For additional information on setting up MLAG, refer to the Dell Networking N-Series MLAG whitepaper on Dell Techcenter at or refer to the User Guide for the particular Dell Networking model at Click Server, Storage, & Networking Networking. 7 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

8 Quality of Service QoS is used to ensure that higher priority data traffic is given the ability to use more bandwidth than less important data that may be tying up network resources. Less significant data traffic can be set to a lower class of service and/or restricted bandwidth. CoS (Class of Service) is a type of QoS that allows preferential treatment of traffic by taking the priority assigned to each packet and mapping it to a specific queue ID. This allows voice traffic to be processed ahead of other traffic in order to alleviate quality issues common in voice traffic. To set the CoS, the commands below should be included when configuring VoIP. These commands are also listed in the example configurations in this document. classofservice dot1p-mapping 5 5 cos-queue strict 5 The first command, classofservice dot1p-mapping 5 5, maps the 802.1p user priority (or class of service) found in the VLAN tag of the packet to the traffic class (also referred to as the egress CoS queue). This determines the egress CoS queue to which the packet is assigned. In this example the first 5 is a filter to identify each incoming packet with an 802.1p user priority of 5 and place it in the egress CoS queue 5 (see Figure 3). Dot1p is short for 802.1p, or QoS found at the MAC layer. There are a total of eight (0-7) user priorities available in the 3-bit 802.1q tag, with each class associated with particular traffic types. In general, the lower priorities like 0 and 1 provide best effort for less significant types of traffic, while the highest priorities of 4 through 7 are reserved for the more critical time-sensitive data traffic like voice and video. For most implementations across the industry, priority 5 is used for voice traffic only in order to minimize latency and jitter. The second command, cos-queue strict 5, defines the highest priority (strict) for the queue. By setting queue 5 to strict, traffic in this queue will be processed and forwarded before any packets in the remaining (weighted) queues are processed. If multiple queues are set to strict, traffic in the highest numbered strict queue are sent first, then the next lower numbered queue, and so on. By default, queues are weighted. Use the show classofservice dot1p-mapping command to see current mapping of each priority. Use the show class-map to see the current scheduler modes for each queue. 8 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

9 Figure q Frame using CoS queuing Bandwidth for weighted queues, which is defined by the number of bytes it processes and not number of packets, is calculated in this way by default: 1. Add 1 to each queue number to find the weight of the queue. For example, queue 6 has a weight of 7. Queue Id Add 1 Weight Total weight of all queues: 22 Note: Queue 5 is not listed above because it is in strict mode 2. Add together all weights of the queues. Divide the weight of each weighted queue by the total weight of all weighted queues to find the bandwidth for that queue, as shown in Figure 4. 9 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

10 Queue Id Add 1 Weight Bandwidth ~ 4% (1/22) % (2/22) % (3/22) % (4/22) % (5/22) % (7/22) % (22/22) Figure 4 Graphic showing default bandwidth for weighted queues In another example, let s say both queue 4 and 5 are set to strict and all other queues remain at the default of weighted. Minimum bandwidth is at the default of 0 for all queues. Packets arrive at the same time for all seven queues. In this case, all traffic entering queue 5 will be processed until it is empty. Then all queue 4 traffic will be processed. Finally, simultaneous processing of queues 6, 3, 2, 1, and 0 is performed with respective bandwidths of 41%, 23%, 18%, 12%, and 6%. Since queue 6 is the highest priority, it receives the most bandwidth of the weighted queues. The minimum bandwidth can also be set for each queue which overrides both the strict and weighted settings. This can limit the overall bandwidth used by a strict queue. For example, the highest numbered strict priority queue will receive no more bandwidth than 100% minus the sum of the minimum bandwidths percentages assigned to the other queues. DiffServ for VoIP DiffServ (Differentiated Services) works for layer 3 much like 802.1p CoS queuing works in layer 2. It enables traffic to be classified into streams and given certain QoS treatment in accordance with defined per-hop behaviors. For packet classification, it uses a 6-bit value known as the DSCP (Differentiated Services Code Point) found in the IP header. Priority queuing can be based on either the 802.1p priority tag or the DSCP priority tag, but not both. Layer 2 switches have the ability to classify traffic based on the DSCP as well. 10 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

11 The Dell Networking N2000, N3000, and N4000 Series Switches User Configuration Guide provides comprehensive instructions on how to configure DiffServ as well as a complete DiffServ for VoIP example in chapter 40. The example provides the CLI commands required to setup DiffServ on a router to allow low latency, high quality calls across the internet. Additional information regarding QoS settings can also be found in the Dell Networking N2000, N3000, and N4000 Series Switches CLI Reference Guide at 11 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

12 COMBO P 23 10GBASE-T MODULE Stack No. 1 SFP COMBO P 23 10GBASE-T MODULE 1 2 Stack No. 1 SFP VoIP Example This section provides step-by-step guidance on configuring a VOIP deployment, including setting up a 3CX call manager, configuring the switches and phones, establishing calls, high availability and QoS. Complete switch configurations are included, providing all required CLI (Command Line Interface) commands for the Dell N-Series switches. 3.1 Configuring the Dell Networking N4000 Using an MLAG topology is not a requirement for a successful implementation of VoIP, but it does contribute to resilient networks targeting 24/7 access to VoIP operations. This section provides instructions on setting up two N4000 switches in an MLAG domain in order to provide this high availability and resiliency to the VoIP network. A special connection known as a Peer Link is used to connect the two N4000 switches so that they appear as a single switch to partner devices. In the figure below, there are two peer switches connected via the red cable and two partner switches, each connected to both peer switches. Each partner must be directly connected to both MLAG peer switches in order to take advantage of the MLAG feature. Dell Networking N4064F Peer Link Dell Networking N4064F Port Channel 1 (1/0/26) (1/0/32) (1/0/26) (1/0/32) Port Channel 2 Port Channel 128 MLAG (Te1/0/1) MLAG (Te1/0/2) (Te1/0/1) (Te1/0/2) Dell Networking N3024P (partner device for servers or phones) Dell Networking N3024P (partner device for servers or phones) Figure 5 Configuring a High Availability MLAG for VOIP Follow the steps below to configure the MLAG domain and set the CoS. Enter the following commands on both peer switches before enabling MLAG (using the feature vpc command) on each one. Each column below contains commands that can be cut and pasted into a CLI session. 12 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

13 Primary MLAG Peer (N4064F) Secondary MLAG Peer (N4064F) Description of commands configure vlan 100,200 configure vlan 100,200 Create 2 VLANs, one for voice and another for data interface vlan 100 ip address /24 interface vlan 200 ip address /24 interface port-channel 128 description "MLAG-Peer-Link" spanning-tree disable switchport mode trunk vpc peer-link interface fortygigabit 1/0/2 channel-group 128 mode active description "MLAG-Peer-Link" interface port-channel 1 switchport mode trunk switchport trunk allowed vlan 100,200 vpc 1 interface port-channel 2 switchport mode trunk switchport trunk allowed vlan 100,200 vpc 2 interface tengigabit 1/0/26 channel-group 1 mode active description "MLAG-Partner-Switch-link" interface tengigabit 1/0/32 channel-group 2 mode active description "MLAG-Partner-Switch-Link" classofservice dot1p-mapping 5 5 cos-queue strict 5 voice vlan feature vpc vpc domain 1 peer-keepalive enable interface vlan 100 ip address /24 interface vlan 200 ip address /24 interface port-channel 128 description "MLAG-Peer-Link" spanning-tree disable switchport mode trunk vpc peer-link interface fortygigabit 1/0/2 channel-group 128 mode active description "MLAG-Peer-Link" interface port-channel 1 switchport mode trunk switchport trunk allowed vlan 100,200 vpc 1 interface port-channel 2 switchport mode trunk switchport trunk allowed vlan 100,200 vpc 2 interface tengigabit 1/0/26 channel-group 1 mode active description "MLAG-Partner-Switch-Link" interface tengigabit 1/0/32 channel-group 2 mode active description "MLAG-Partner-Switch-Link" classofservice dot1p-mapping 5 5 cos-queue strict 5 voice vlan feature vpc vpc domain 1 peer-keepalive enable Configure an IP address for each vlan Configure the port channel for the peer link Identify and configure the peer link interface Create a LAG for partner switch to pass traffic Assign a unique id for the partner switch Create a LAG for another partner switch to pass traffic Assign a unique id for the partner switch Assign interfaces to connect to partner switch LAG Assign interfaces to connect to partner switch LAG Set 802.1p priority and traffic class globally. Set the queue to strict Enable Voice VLAN Enable the MLAG 13 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

14 The classofservice dot1p-mapping command in the preceding example is used to map an 802.1p user priority (0-7) to a traffic class queue (0-6). The command can be issued on individual interfaces or globally, as seen here, in order to configure the same mapping on all interfaces. Ordinarily, if only user priority 5 (for voice traffic) has been changed, and has been set to traffic class queue 5, any packets coming onto an ingress port with a priority of 5 will be forwarded by the egress port before lower class packets (0-4), and after higher class packets (6). However, for this example a strict queue has been configured using the cos-queue strict command, explained below, which will take precedence over the other queues. All other 802.1p user priorities remain at their default traffic classes. Use the command show classofservice dotp-mapping (as shown in Figure 3) to see what traffic class queues are currently mapped to each 802.1p user priority. Hint: Terms used in CoS are often used interchangeably. Whenever 0-6 is discussed, it is referring to traffic class, CoS queue, or simply queue. Whenever 0-7 is discussed, it is referring to priority tag, 802.1p tag, 802.1p packet priority, 802.1p user priority, or simply priority. The cos-queue strict command is used to configure a strict priority scheduler mode for the queues. In this example queue 5 is set to a strict scheduler type. All other queues (0-4, 6) are kept at the default weighted scheduler type as can be seen using the following command. console# show interfaces cos-queue Global Configuration Interface Shaping Rate... 0 kbps WRED Decay Exponent... 9 Queue Id Min. Bandwidth Scheduler Type Queue Management Type Weighted Tail Drop 1 0 Weighted Tail Drop 2 0 Weighted Tail Drop 3 0 Weighted Tail Drop 4 0 Weighted Tail Drop 5 0 Strict Tail Drop 6 0 Weighted Tail Drop 14 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

15 3.2 Configuring the Dell Networking N3000 This section provides instructions on setting up an N3000 PoE switch to connect to the N4000 switch MLAG domain. The N3000 will need to connect to both peer switches in order to take advantage of the MLAG technology. Voice VLAN is the preferred solution for enterprises wishing to deploy a large scale voice service. Though the Auto VoIP feature is a simpler alternative to Voice VLAN, it is limited to 16 sessions, Therefore, in order to scale, the examples in this document only use the Voice VLAN solution. For information on setting up Auto VoIP, refer to the Dell Networking N2000, N3000, and N4000 Series Switches User Guide. Enter the following commands (or cut and paste them) into the N3024P command line. The first partner switch configuration below shows commands that will allow a connection to the 3CX server (in port 1/0/1) and IP phones on all other ports. First Partner Switch N3024P (with 3CX Server) configure vlan 100,200 interface vlan 100 ip address /24 interface vlan 200 ip address /24 interface port-channel 2 switchport mode trunk switchport trunk allow vlan 100,200 interface tengigabit 1/0/1 channel-group 1 mode active interface tengigabit 1/0/2 channel-group 1 mode active interface gigabit 1/0/1 switchport access vlan 100 voice vlan 100 voice vlan auth disable interface range gigabit 1/0/2-24 switchport mode general switchport general allow vlan add 100 tagged switchport general allow vlan add 200 voice vlan 100 voice vlan auth disable Description of commands create same VLANs on switch partner Configure an IP address for each vlan; one for voice traffic and another for regular traffic configure the port channel trunk for the switch partner link. Using Po2 here to match the MLAG Po2 configuration it is connecting to, though matching is not required Assign interface to MLAG (channelgroup) Assign second interface to MLAG (channel-group) Assign access port for the 3CX server, making sure it is in the Voice VLAN. Assign access ports to the VLAN for phones and other hosts that will be using the MLAG. Specify the voice vlan, and disable authentication. 15 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

16 First Partner Switch N3024P (with 3CX Server) classofservice dot1p-mapping 5 5 cos-queue strict 5 voice vlan Description of commands Set 802.1p priority and traffic class globally (can also be set per port) Enable Voice VLAN Second Partner Switch N3024P configure vlan 100,200 interface vlan 100 ip address /24 interface vlan 200 ip address /24 interface port-channel 1 switchport mode trunk switchport trunk allow vlan 100,200 interface tengigabit 1/0/1 channel-group 1 mode active interface tengigabit 1/0/2 channel-group 1 mode active interface range gigabit 1/0/1-24 switchport mode general switchport general allow vlan add 100 tagged switchport general allow vlan add 200 voice vlan 100 voice vlan auth disable classofservice dot1p-mapping 5 5 cos-queue strict 5 voice vlan Description of commands create same VLAN on switch partner Configure an IP address for each vlan; one for voice traffic and another for regular traffic configure the port channel trunk for the switch partner link Assign interface to MLAG (channelgroup) Assign second interface to MLAG (channel-group) Assign access ports to the VLAN for phones and other hosts that will be using the MLAG. Specify the voice vlan, and disable authentication Set 802.1p priority and traffic class globally. Set queue 5 to strict Enable Voice VLAN Connect all cables as shown in Figure 5. Run the show vpc brief command on the Primary MLAG peer to verify that MLAG is up. The VPC admin status, Keep-alive, and VPC operational status should all show Enabled. 16 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

17 Primary MLAG Peer console# show vpc brief VPC admin status... Enabled Keep-alive admin status... Enabled VPC operational status... Enabled Self role... Primary Peer role... Secondary Peer detection admin status... Disabled must show Enabled must show Enabled must show Enabled verify that Self role is Primary; if not, then attach to other MLAG peer for more complete information Peer-Link details Interface... Po128 Peer-link admin status... Enabled Peer-link STP admin status... Disabled Configured VLANs... 1,100,200,300 Egress tagged VLANs ,200,300 VPC Details Number of VPCs configured... 2 Number of VPCs operational... 2 all configured VPCs should also show operational VPC id# Interface... Po1 Configured VLANs... 1,100,200,300 VPC interface state... Active Local Members Status Te1/1/1 Up Peer Members Status Te1/1/1 Up VPC id# Interface... Po2 Configured VLANs... 1,100,200,300 VPC interface state... Active Local Members Status Te1/1/2 Up Peer Members Status Te1/1/2 Up 17 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

18 For more information on setting up MLAGs, refer to the Dell Networking N-Series MLAG deployment guide which can be downloaded here: Configuring the 3CX PBX The 3CX call manager is used in this paper to demonstrate the voice features of the Dell Networking N- Series switches. Note: A free version of the 3CX VoIP Phone System for Windows software can be downloaded here: VoIP configuration guides for the 3CX software can be found here: There are a few tasks that need to be considered before and during the installation of the 3CX server. Use the checklist below in preparing the server. 1. Identify a server to be used as a 3CX PBX and DHCP server. Be sure to follow hardware requirements for a 3CX install. 2. Set a static IP address on the server NIC before installing the 3CX software. Don t use DHCP. 3. In Windows, go to Control Panel, Hardware, Power Options and change the Preferred Plans to High performance. For this example, the 3CX and DHCP were installed on a Dell PowerEdge R620 running Microsoft Windows Server 2012 R2 Standard. 3CX Phone System version 12.0 was used. The installation file (112 MB) was copied to the desktop and executed. All defaults were taken during the simple installation. The server must be configured for each phone that will be using it. To configure a phone, an extension (phone number) with an associated ID and password must be set., Perform the following steps to create an extension. 1. Open the 3CX Phone System Management Console. 2. Select Extensions from the left navigation menu. 3. Click Add Extension. 4. Enter the desired extension number into the Extension Number field. 5. Enter an ID and Password into the appropriate fields. 6. Press OK. Repeat the steps above to create additional extensions. At least one extension should be created for each IP phone to be installed on the network. 18 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

19 Select Extension Status from the left navigation menu to see when phones have registered. A green light is shown for registered phones, and a red light is shown for unregistered phones. All extensions for registered phones are enabled for making calls. An amber light (Connected) means the phone has been plugged in and is registering, but has not finished initiating. Follow the instructions below or from the phone manufacturer to configure each phone type. Return to the status page to verify successful registrations. Once registration is achieved, the IP phone can call all other registered IP phones listed in the management console. Once the extensions are entered and each phone has registered with the call manager, testing the configuration is as easy as making a phone call. Using two phones on the network, call the extension of one from the other. Antivirus and Firewall Considerations To alleviate write delays in 3CX, antivirus programs should be configured so they will not scan the following directories: \Program Files\3CX PhoneSystem\* \ProgramData\3CX\* The 3CX server may also require certain ports to be open when communicating with remote extensions from behind a firewall. The following link shows configurations for popular firewalls 19 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

20 3.4 Configuring VoIP phones Several IP phone models are fully supported by the 3CX call management server. For a complete list of phones supported visit Other IP phones require a particular call manager software, appliance, or controller in order to change settings. This includes but is not limited to the following: Select Avaya phones require the Avaya Communication Manager Select Cisco phones requires the Cisco Call Manager Select Mitel phones require the Mitel Controller Phones can be registered and managed through their web user interface once they have acquired an IP address from the DHCP server. The basic DHCP process is as follows: 1. Install a DHCP server on the network where each phone can get an IP address. For this example, the Windows DHCP server was installed on the same server as the 3CX server. 2. DHCP needs to provide IP addresses to each phone. These addresses need to be in the same subnet as the voice VLAN. 3. Once a phone has obtained an IP address, it will be displayed on the phone s screen, or can be found in the DHCP server by matching the MAC address of the phone with the IP address. 4. Log into the phone s web interface using the IP address in the URL field. 5. On each phone, set the IP address of the phone management server, which is the 3CX server in this example. The IPv4 range of addresses were used in this example, with the first phone given the address of Entering in the URL will allow access to the management software for this phone Polycom Use the instructions below to configure a Polycom SoundPoint IP 335 VoIP phone. Setup of other Polycom phone models may differ slightly. Connect the phone to the network. Once it has an IP address, go to the web user interface of the phone. For this example, IP address was assigned to the Polycom phone. Login to the interface and perform the following steps: 1. From the Polycom configuration screen, Select Lines from the menu. 2. Set the Address field to 102 (or the predetermined extension for this phone). This will be the extension of the phone and correlates with the extension given when setting up the 3CX call management server in Configuring the 3CX PBX above. 20 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

21 3. Set the Authentication User ID. In this example 102 was assigned. 4. Provide the Authentication Password. This should correlate with the password given to this extension when setting up the 3CX call management server. 5. Under Server 1, enter the IP address of the 3CX server into the Address field. 6. Enter 5060 into the Port field. After entering all required information, the screen should reflect the settings shown in Figure 6. Figure 6 Polycom IP phone settings Scroll to the bottom of the screen and click Submit to save these settings to the phone. Refer to the call manager server to verify the phone is being registered. 21 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

22 3.4.2 SNOM Use the instructions below to configure an SNOM 821 VoIP phone. Setup of other SNOM phone models may differ slightly. Connect the phone to the network. Once it has an IP address, go to the web user interface of the phone. For this example, IP address was assigned to the SNOM phone (a login may be required). Perform the following steps: 1. From the Welcome screen, click on Identity 1 in the left-hand menu. 2. Set the Account field to 103 (or the predetermined extension for this phone). This will be the extension of the phone and correlates with the extension given when setting up the 3CX call management server. 3. Provide the password. This should correlate with the password given to this extension when setting up the 3CX call management server. 4. Set the Registrar field to the IP address of the 3CX server. For this example, it is Settings should reflect the ones shown in Figure 7. Figure 7 SNOM IP phone settings. 5. Press the Apply button. Then press Re-Register. Refer to the call manager server to see the phone being registered. 22 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

23 PowerEdge COMBO P 23 10GBASE-T MODULE 1 2 Stack No. 1 SFP COMBO P 23 10GBASE-T MODULE 1 2 Stack No. 1 SFP Connecting PCs to Phones Most IP phones today have an access port built in to the phone allowing the user to attach a PC. This enables the end user to have a single data cable at their desk for both voice traffic and data traffic to and from the computer. To allow data traffic to pass through the switches and phones without hindering the voice traffic, the data and voice are placed into separate VLANs. Figure 8 depicts two VLANs and how different device types are associated with each VLAN. Dell Networking N4064F Dell Networking N4064F Dell Networking N3024P Dell Networking N3024P 3CX PBX DHCP Server VLAN 100 (voice) VLAN 200 (data) Figure 8 Connecting PCs to IP Phones The configurations in this document already separates the voice and data traffic. The only setting that remains to be configured to allow the phones to see (and then pass) non-voice traffic is the PVID (Port VLAN ID). The PVID will take all incoming untagged frames, like those found in VLAN 200 (non-voice VLAN), and tag each one as a VLAN 200 frame. Setting the PVID on a switch port with both phone and PC connected, will allow proper operation of both voice on the phone and data on the PC. Use the following commands to set the PVID on a port. For this example, the phone plugged into port gigabitethernet 1/0/14 has a PC connected that needs access to data VLAN VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

24 Commands configure interface Gi1/0/14 switchport mode general switchport general pvid 200 switchport general allowed vlan add 200 switchport general allowed vlan add 100 tagged voice vlan 100 voice vlan auth disable Description of commands set the PVID for untagged (nonvoice VLAN 200) frames these commands are required on the port to separate voice and data traffic The commands above are used to demonstrate multiple VLANs that separate traffic types so voice traffic does not interfere with data traffic, and vice versa. In most real world cases however, you should consider having the PC use 802.1x, and configure authenticated, unauthenticated and guest VLANs on your network. Refer to the Dell N-Series User Guide for more information. 24 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

25 PowerEdge Stack No. 1 SFP Troubleshooting Tips The following section provides tips on how to help alleviate problems you may encounter when configuring the network. 4.1 Problem Isolation To help troubleshoot most issues, it is recommended that different areas of the configuration be isolated. The following topology (a subset of the full topology shown in Figure 1), uses only the configuration for the N3000 shown in section 3.2, but is fully functional and can be used to test the switch VoIP settings, the IP phones, the 3CX server, and DHCP on a single switch. Dell Networking N3024P 2 COMBO P 3CX PBX Server DHCP Server VLAN VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

26 4.2 Show Commands The following is a list of helpful show commands that can be used to troubleshoot the concepts in this document. Command show lldp remote-device all LLDP Remote Device Summary Local Interface RemID Chassis ID Port ID System Name Gi1/0/ F67:P1 snom821 Gi1/0/23 2 D0:67:E5:95:0B:83 Te1/1/2 Gi1/0/24 1 D0:67:E5:95:0B:57 Te1/1/2 Description displays LLDP supported phones (e.g. SNOM), that have been discovered by the switch show lldp remote-device detail gigabitethernet 1/0/10 LLDP Remote Device Detail Local Interface: Gi1/0/10 run on the port where the LLDP phone resides for more information Remote Identifier: 6 Chassis ID Subtype: Network Address Chassis ID: Port ID Subtype: Local Port ID: F67:P1 System Name: snom821 System Description: snom;snom821-sip ;lid: Port Description: NET PORT System Capabilities Supported: bridge, telephone System Capabilities Enabled: bridge, telephone Time to Live: 145 seconds show isdp neighbors Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge, S - Switch, H - Host, I - IGMP, r - Repeater Device ID Intf Holdtime Capability Platform Port ID SEP0004f24cfd5d Gi1/0/8 124 H Polycom SoundPoi Port 1 N Gi1/0/ R N4064F Te1/1/1 N Gi1/0/ R N4064F Te1/1/1 displays ISDP supported phones (e.g. Polycom) that have been discovered by the switch show isdp neighbors gigabitethernet 1/0/8 detail Device ID SEP0004f24cfd5d run on the port where the ISDP phone resides for 26 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

27 Command Address(es): IP Address: Capability Host Platform Polycom SoundPoint IP 335 Interface Gi1/0/8 Port ID Port 1 Holdtime 142 Advertisement Version 2 Time when last changed 7 days 23:51:08 Version : BootROM: 4.3.1, App: Description more information show voice vlan Administrative Mode... Enable verifies voice vlan is enabled globally show voice vlan interface gigabitethernet 1/0/8 Interface. Gi1/0/8 Voice VLAN Interface Mode... Enabled Voice VLAN ID Voice VLAN COS Override... False Voice VLAN DSCP Value Voice VLAN Port Status... Enabled Voice VLAN Authentication... Disabled Voice Device MAC Address F24C.FD5D. displays voice VLAN details for a port show interface cos-queue Global Configuration Interface Shaping Rate... 0 kbps WRED Decay Exponent... 9 Queue Id Min. Bandwidth Scheduler Type Queue Management Type Weighted Tail Drop 1 0 Weighted Tail Drop 2 0 Weighted Tail Drop 3 0 Weighted Tail Drop 4 0 Weighted Tail Drop 5 0 Strict Tail Drop 6 0 Weighted Tail Drop displays priority modes for all queues. Strict queues are processed before Weighted queues 27 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

28 Command show classofservice dot1p-mapping User Priority Traffic Class Description displays the queue (Traffic Class) to which each User Priority is assigned 4.3 Interference of other Applications As with most time-sensitive applications, other programs running on the server such as antivirus applications and firewalls can interfere with proper operation. Be sure to check the recommendations of the call management application you are using to avoid these type of issues. To alleviate write delays in 3CX for example, antivirus programs should be configured so they will not scan the following directories: \Program Files\3CX PhoneSystem\* \ProgramData\3CX\* The 3CX server may also require certain ports to be open when communicating with remote extensions from behind a firewall. This link shows configurations for popular firewalls : 28 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

29 Appendix A.1 Additional Resources Support.dell.com is focused on meeting your needs with proven services and support. DellTechCenter.com is an IT Community where you can connect with Dell Customers and Dell employees for the purpose of sharing knowledge, best practices, and information about Dell products and installations. Referenced or recommended Dell publications: Dell Networking Support - Dell TechCenter (community forums and blogs for Dell customers) - Dell Networking Whitepapers - Dell Networking N2000/N3000/N4000 User Guides and Firmware downloads - d= Dell Force 10 VoIP Deployment Feature Note VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

30 A.2 Configuration details This paper was compiled using the following components and versions. Component Dell Networking N3000 series, N4000 series 3CX Phone System Management Console Dell Server Version firmware V PowerEdge R620 Microsoft Windows Server 2012 R2 Standard Polycom VOIP phone SoundPoint IP 335 SNOM VOIP phone Model 821 A.3 Design Validation During the confirmation of the scenario in this paper, high volume Ixia VoIPSIP validation tests were performed on the overall topology and awarded a score of A for the number of calls that were successfully executed, as well as an A for the Voice Quality. During the 2 hour test, over 1.6 million calls were attempted and 1.6 million calls were completed, with 0 failures. Zero calls were dropped, and zero packets were lost. The setup involved using 30,000 virtual phones connected to 20 ports, with half of the phones calling the other half and talking for an average of 33 seconds. Audio statistics showed nearly one trillion bytes sent and one trillion bytes received. A second validation test was performed where switches were oversubscribed to the point of dropping packets in order to test the strict scheduling mode for queue 5. During this 2 hour test, normal layer 2 packets were dropped in other queues but no calls were dropped in the strict queue, which contained the highest priority of all traffic, being voice traffic. MLAG failover was verified throughout all test efforts and the network remained resilient in passing voice and data traffic during switch and cable failures. 30 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

31 Glossary of Terms Access Layer: The access layer is the layer of the network used by end users and end user devices to connect to the network. Bandwidth: Bandwidth specifies the amount of data that can be transmitted in a fixed amount of time. Typically expressed in bits per second or multiples of bits per second (bits/s,kbits/s,mbit/s,gbit/s). CLI (Command Line Interface): Text-based telnet, secure shell (SSH), or serial type interface that is used for issuing commands to a device. CoS (Class of Service): CoS allows preferential treatment to be given to certain types of traffic over other types. CoS helps to streamline network traffic by taking the priority assigned to the packet and mapping it to a specific queue ID (queue mapping). DHCP (Dynamic Host Configuration Protocol): A network management protocol used to dynamically assign network settings to devices connected to a network. IP Phone: A phone that utilizes an IP (Internet Protocol) network to transmit calls over the a LAN or internet as opposed to the circuit-switched telephone used by traditional Public Switched Telephone Networks (PSTNs). LLDP (Link Layer Discovery Protocol): LLDP is a vendor neutral protocol used to obtain and share information about neighboring equipment. LLDP-MED (Link Layer Discovery Protocol Media Endpoint Discovery): LLDP-MED is an extension of LLDP, which allows discovery of VoIP phones and allows the creation of location databases for the telephone locations. MAC Address (Media Access Control address): A MAC address is a hardware specific address that uniquely identifies each node of a network. MAC addresses are assigned typically by the vendors of network interface controllers (NIC) and are stored in the hardware. MLAG (Multi-Chassis Link Aggregation Group): MLAG is a type of LAG, which allows link aggregation between multiple devices (chassis). PBX (Private Branch Exchange): A private telephone network used within an enterprise. PoE (Power over Ethernet): Devices that pass electrical power along with data on Ethernet cabling. POE allows a single Ethernet cable to provide both data and electrical power to the devices. QoS (Quality of Service QoS): QoS allows network administrators or engineers to decide how and what network traffic is forwarded according to priorities, application types, and source and destination addresses. Queue: A queue is a group of data packets that are waiting to be transmitted. 31 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

32 SIP (Session Initiation Protocol): SIP is the protocol used to manage multimedia communication including VoIP calls. Traffic Class: Traffic class is associated 1 to 1 with the queue ID, i.e. packets with a class of 4 will be assigned to queue 4. VLAN (Virtual local area network, or Virtual LAN): VLANs are logical subgroups that are partitioned off a physical network in order to create separate broadcast domains. VoIP (Voice over IP): VoIP is the delivery of voice communications and multimedia sessions over an Internet Protocol (IP) network. Voice VLAN: Voice VLAN enables switch ports to carry voice traffic with defined priority. The priority level enables the separation of voice and data traffic coming into the port. 32 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0

33 Support and Feedback Contacting Technical Support Support Contact Information Web: Telephone: USA: Feedback for this document We encourage readers of this publication to provide feedback on the quality and usefulness of this deployment guide by sending an to About Dell Dell is a worldwide leader in data center and campus solutions which includes the manufacturing and distribution of servers, network switches, storage devices, personal computers, and related hardware and software. For more information on these and other products, please visit the Dell website at 33 VoIP CoS queuing on Dell Networking N-Series switches - version 1.0