Microsoft Lync Server 2013 Software Defined Networking (SDN) functionality was added late in the project and used equipment that was available to deploy quickly. This resulted in the implementation of the SDN components in a non- optimal configuration. This configuration included the SDN high availability components but was not designed for optimal high availability. An example of this is the deployment of both Microsoft SDN manager virtual machines on the same physical Hyper-V host. The result was that failure of the virtual machine could be simulated but not the failure of the physical host.
Office Web Apps Server pool Lync Persistent Chat Pool
Lync Front End pool
Lync Back End SQL pool
Lync Director pool Infrastructure Servers
Lync Edge Server pool
Lync Stress & Performance Tools Network Optimizer/ VAN Controller
Test Workstations
Lync PSTN Gateway Simulator
Lync Stress & Performance Tools Lync Stress & Performance Tools
SDN Managers
10.10.10.11 10.10.10.12
10.10.10.13
(Mediation, Archiving & Monitoring co-located on FE)
10.10.10.21 10.10.10.22 10.10.10.31 10.10.10.32 10.10.10.41 10.10.10.42 10.10.10.52 30.30.30.11 30.30.30.12 30.30.30.13 (access) (web) (av) 30.30.30.21 30.30.30.22 30.30.30.23 (access) (web) (av) 10.10.10.02 10.10.10.01 10.10.10.51 3800 Switch-A Top 3800 Switch-B Bottom 10.10.10.81 10.10.10.82 ARCA PSTN Simulator MSR 50-60 Gateway 10.10.10.71
(Archiving & Monitoring DB, Persistent Chat & Compliance
DB co-located on BE) (Active Directory & DNS Servers) 10508 Switch (External Users) 30.30.30.31 20.20.20.125 Not Configured 10.10.10.91 10.10.10.96 30.30.30.85 (Internal Users) 10.10.10.62 (Internal Users) 10.10.10.61 VLANs Configured on Switch
VLAN1: 192.168.1.0 VLAN 10: 10.10.10.0 VLAN 20: 20.20.20.0
IP Routes Configured on Switch 192.168.1.0/24 DG: 10.10.10.0/24 DG: 20.20.20.0/24 DG:
Management Port
IP Address: 192.168.1.210/24
VLANs Configured on Switch
VLAN1: 192.168.1.0 VLAN 10: 10.10.10.0 VLAN 20: 20.20.20.0 VLAN 30: 30.30.30.0 IP Routes Configured on Switch 192.168.1.0/24 DG: 10.10.10.0/24 DG: 20.20.20.0/24 DG: 30.30.30.0/24 DG: Management Port IP Address: 192.168.1.211/24
VLANs Configured on Switch
VLAN1: 192.168.1.0 VLAN 10: 10.10.10.0 VLAN 20: 20.20.20.0 VLAN 30: 30.30.30.0
IP Routes Configured on Switch
192.168.1.0/24 DG: 10.10.10.0/24 DG: 20.20.20.0/24 DG: 30.30.30.0/24 DG: Management Port IP Address: 192.168.1.201/24 DG: Management Port IP Address: 192.168.1.202/24 DG: Management Port IP Address: 192.168.1.200/24 DG: LACP Trunk VLAN 10 and VLAN20
10.10.10.118 10.10.10.126 Port 13 Port 12 Port 10 Port 47 Port 19 Port 18 Port 26 Port 27 LACP Trunk VLAN 10, VLAN20 & VLAN30
The HP Network Optimizer SDN Application automates policy deployment dynamically at the edge of the network on a per- session basis for voice, video, and application sharing to deliver a better user experience. The non-SDN devices in the core network and WAN can then trust the QoS markings securely provisioned via SDN.
Lync Server 2013 SDN functional overview
The process that takes place when SDN is implemented and enabled for the prioritization of Lync session traffic is as follows:
When the call starts
When a desktop sharing, voice, or video session is initiated using a Microsoft Lync client in the campus or branch office, the Lync Server in the data center provides session start details via the UC SDN API. These include source and destination IP address, protocol type, application ports, media type, codec and bandwidth requirements at the start and end of every call.
• Lync Front end Lync SDN Manager (RESTful API)
• Lync SDN Manager HP Network Optimizer/VAN SDN Controller
• HP VAN SDN Controller uses Proactive SDN mode to provision an OpenFlow entry with QoS action DSCP remark OpenFlow-hybrid mode Switch closest to both endpoints
• HP switch modifies/remarks the DSCP value in packets for the first matching entry in the hardware flow table – DSCP markings for non-matching flows will be reset to 0
– DSCP values are based on the Optimizer Global QoS policy settings for given media type – Remarked packet can now be trusted across the core network and WAN
When the call ends
Lync Server in the data center provides session end and call quality details via the UC SDN API at the end of every session.
• Lync Front end Lync SDN Manager (RESTful API)
• Lync SDN Manager HP Network Optimizer/Virtual Application Network (VAN) SDN Controller
• HP VAN SDN Controller deletes the matching OpenFlow QoS entry OpenFlow-hybrid mode Switch closest to both endpoints
The switch will delete stale OpenFlow entries for flows that do not match any packets within the idle timeout (60 seconds for Optimizer).
An in-depth technical white paper describing the HP Network Optimizer SDN Application for Microsoft Lync is available from: http://h20195.www2.hp.com/V2/GetDocument.aspx?docname=4AA5-6601ENW
The SDN components
The following components make up the SDN solution for Lync Server 2013 and allow for the prioritization of the Lync session traffic.
• Microsoft Lync SDN API
• Microsoft SDN Manager server
• HP Network Optimizer/VAN SDN Controller The Lync SDN API has two components:
• Lync Dialog Listener (LDL) that is installed on the Lync Front End servers
• Lync SDN Manager (LSM) that is installed on the Microsoft SDN Manager servers
The Microsoft Lync SDN API was installed on each Lync Server 2013 running the Front End server role. The Microsoft SDN Manager functionality was tested with two different designs:
Lync SDN HA mode: two SDN Manager servers were configured on two VMs. One SDN Manager acted as primary and the other SDN Manager acted as secondary. Each LDL was configured to connect to both the primary and secondary LSM servers. In case the primary LSM fails, the secondary LSM takes over.
Figure 27. Lync SDN Call Flow – HA
Lync SDN non-HA mode: three SDN Manager servers were configured on three VMs. One LDL would point to only one LSM which means one FE was linked to only one LSM.
Figure 28. Lync SDN Call Flow – non-HA
Both the HA and non-HA modes were tested.
The HP Network Optimizer/VAN SDN Controller communicates with the network hardware and controls the network traffic through session prioritization by communicating with network devices using OpenFlow protocol. The HP Network Optimizer/VAN SDN Controller was deployed on a ProLiant physical server and hosted the HP Network Optimizer application. HP SDN Controller with HP Network Optimizer Lync Client Lync client Media QOE Data QOE Data Signaling Signaling Lync FE 1 LDL LDL LDL Lync FE 2 Lync FE 3 NETWORK SDN Manager
(Primary) SDN Manager(Secondary)
LSM LSM 3800 Switch OpenFlow Enabled 3800Switch OpenFlow Enabled 10508 Switch OpenFlow Optional MSR 50-60
PSTN Gateway Arcatech emutel | Harmony
PSTN Simulator
Front End Server Pool
Microsoft Lync Stress and
Performance tool Servers Microsoft Lync Stress and Performance tool Servers Microsoft Lync Stress and Performance tool Servers
Microsoft Lync Stress and Performance tool Servers as PSTN
Gateway XML XML XML XML XML XML XML XML XML XML
Note
Since the addition of SDN happened late in the project cycle, a trial license for the HP Network Optimizer/VAN SDN Controller was used. This resulted in a single instance of HP Network Optimizer/VAN SDN Controller being installed with a trial version of the HP Network Optimizer application and configured to process Lync communication sessions. With the trial version, the HP Network Optimizer/VAN SDN Controller could actively control a maximum of 100 concurrent sessions that it received from SDN Manager. This limited the number of Lync sessions on which traffic prioritization was applied. The Lync session information beyond 100 sessions (the limit of the trial license) were sent by the SDN Manager and processed by the HP Network Optimizer/VAN SDN Controller but no DSCP information was configured on the HPN 3800 OpenFlow switches for traffic prioritization of Lync sessions.
SDN control and packet processing
The network configuration to support SDN uses OpenFlow compliant switches with an appropriate level of firmware to support, accept and act upon SDN control commands that allow Quality of Service (QoS) information to be tagged to specific communication streams between a set of IP addresses and network port numbers.
SDN is separated into two areas: control and optimized packet processing. Control is deployed in a centralized manner while optimized packet processing is distributed across all switches. These areas are also referred to as the control plane and the forwarding plane.
The following components support the ability to enable SDN traffic prioritization for Lync traffic:
• HP Network Optimizer/VAN SDN Controller software is the central point for control and automation of your SDN-enabled network. The HP Network Optimizer/VAN SDN Controller can be scaled out by using controller teaming and high availability is available through the use of teaming to provide for failover in the event that one controller fails.
• The SDN Manager communicates with the Microsoft Lync SDN RESTful API that is installed on each Lync Front End server. The Microsoft Lync API provides the SDN Manager with information on the type of communication traffic that is being sent during a conversation by transmitting the IP address and network port being used on each Lync client. The type of traffic could be voice, video or any other Lync communication. The SDN Manager then communicates the session type information to the HP Network Optimizer/VAN SDN Controller.
• The HP Network Optimizer/VAN SDN Controller application is deployed on the HP Network Optimizer/VAN SDN Controller. This application controls the SDN information and the HP Network Optimizer/VAN SDN Controller performs traffic prioritization by modifying the flow table on the 3800 switches using OpenFlow.
The Lync Dialog Listener (LDL) is the component of the Lync SDN API that is installed on each Lync Front End server. The LDL listens to the encrypted Lync session information such as session details and media quality details and sends it to LSM. The SDN lab configuration consisted of the following components: Microsoft Lync SDN API 2.1, HP VAN SDN Controller (v2.3.6) with HP Network Optimizer application (v1.1.6).
The Microsoft Lync SDN API 2.1 consisted of two components: Lync Dialog Listener (LDL) and Lync SDN Managers (LSM). A Lync Dialog Listener (LDL) captures signaling and quality observations about media traffic between Lync endpoints. A Lync SDN Manager (LSM) collects the data from one or more LDLs and distributes it to HP VAN SDN Controller.
“Microsoft Lync Dialog Listener 2.1” was deployed on the three Lync Front End servers that were on VLAN10. Two SDN managers (Microsoft Lync SDN Manager 2.1) were deployed on separate virtual machines (two VMs on the same physical server). Each LDL could communicate with both primary and secondary LSM. This is the HA configuration for LDL-LSM. If Primary LSM fails, secondary LSM takes over. The following screenshot shows how the LDLs are configured to point to primary and secondary LSM.
Figure 29. Microsoft SDN API: LDL Configuration
The HP Network Optimizer/VAN SDN Controller was deployed on a separate server connected to VLAN20 (physically connected to 3800-B switch). VLAN 20 was created exclusively for SDN control traffic to separate it from Lync user traffic. The HP Network Optimizer/VAN SDN Controller can prioritize the Lync Media traffic from Lync clients using OpenFlow protocol. The types of Lync media traffic involving two or more Lync endpoints include audio and video calls, and
application-sharing. Per the SDN standards, the switches that connect to Lync clients are supposed to be OpenFlow enabled, whereas the other network switches in the path that the Lync session traverses do not necessarily need to support
OpenFlow but must be able to honor QoS. In this configuration, the two 3800 switches were configured with OpenFlow because they were connected to Lync clients but the HP 10508 switch was not enabled for OpenFlow (it simply honored the QoS information passed to it by the 3800 switches).
Figure 27 also depicts the call flow for SDN control for the sessions between or amongst Lync clients. LDL is deployed as a Windows service on the Lync Front End server. LDL is configured to send Lync call and quality data to LSM. LSM is a Windows service deployed on a separate server (virtual or physical). In this lab configuration LSM was deployed on virtual servers. The LSM is responsible for processing the dialog events received from the LDL component. It maintains state of the individual real-time streams – including whether the stream has started, ended, updated, and more – and sends the resulting XML data to the configured network management system (HP Network Optimizer/VAN SDN Controller in this configuration). LSM parses the message and selects the data that is related to quality of Lync audio, video or application sharing session and posts it in XML format to the HP Network Optimizer/VAN SDN Controller. The HP Network Optimizer/VAN SDN Controller uses a web service to receive the XML data from LSM, therefore the SDN controller’s Web service address must be
configured on the LSM.
On receiving the Lync call and quality data session information, the HP Network Optimizer/VAN SDN Controller can prioritize the Lync media traffic by modifying the DSCP value (pertaining to a specific session) in the flow tables of the HP 3800 switches. The HP SDN controller uses the OpenFlow protocol to communicate with the HP 3800 switches. The HP SDN Controller sets the desired value of DSCP to 46 for the Lync session that it wants to prioritize and checks that the configured value of DSCP in the HP 3800 switches is 46 for that session. If the quality reported by LSM for any specific Lync session is good, the HP Network Optimizer/VAN SDN Controller does not prioritize that session and does not modify the DSCP value from the default of DSCP=10 which is prioritized as Best Effort. When a bad quality session is reported by the Lync environment, the SDN controller modifies the DSCP value in the flow table in both 3800 switches that are connected to the Lync users. The HP 10508 being the core switch and not directly connected to the Lync end users, need not necessarily be OpenFlow compliant (it needs to honor the QoE configuration only).
The LSMs can be configured in HA or non-HA mode. In HA mode two LSM are needed, one Primary and another Secondary. The Failover from Primary to Secondary is automatic. The primary and secondary LSM do not share the states. In non-HA mode, each LSM is in a standalone mode.