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MS-720 - Plan and Configure Direct Routing

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Notes from March 2022

Plan and Design Direct Routing Call Flows​

  • Overview

    • Different certified SBCs for PSTN connectivity options
    • Licensing Required for Direct Routing
    • Steps required to deploy Direct Routing
    • Benefits of optimizing media flow

  • Microsoft Certified SBCs

    • Can be deployed into a datacenter, onpremise
    • Some are always available on AWS or Azure
    • Examples
      • AudioCodes
      • Ribbon communications
      • Oracle
      • Cisco
      • Avaya
      • TE-SYSTEMS

  • Teams Environment

    • Microsoft PhoneSystem is hosted in Cloud and is part of M365
    • SBC
    • Users are working in hybrid model
    • Service Providers connect those users to the PSTN world

  • Licensing Required for Direct Routing

    • Microsoft 365 account
    • Microsoft Teams - Any BusinessLicense
    • Microsoft Phone System - Add-on License
    • E1/E5 with Phone System, E5 included, BusinessVoice included

  • Steps required to deploy Direct Routing

    1. On-Premise or Cloud Basec SBC
    2. Endpoints Licensing
    3. SBC
    4. FQDNs and Certificates
      • FQDN for the SBC
      • The certificates installed on the SBC
    5. IP Ranges and Firewall
      • SBC needs to connect to Mirosoft
      • Ports needs to open for voice
    6. Voice Routing (Optional)

  • On-premise vs. Cloud Based SHBC Hosting, SBC

  • Connectivity

    • Allows Teams to Interconnect with other Voice Components

  • Security

    • Acts as a Firewall for Session Initiation Protocol (SIP) Traffic

  • Media Services

    • Transcodes and Supports Voice and Video Calls

  • Voice Routing

    • Objects used to configure Voice Routing
      • Voice routing policy
      • PSTN Usage Records
      • Voice Route
      • Dial Plan
      • Gateway (Trunk)
    • After the SBC has a connection to M365 a voice route with regext pattern must be configured
      • A voice route is selected by priority
      • Voice routes are assigned to the PSTN Usage Record and not the users
      • PSTN Usage Record are members of a Voice Routing Policy

  • Optimize Media

    • Media Bypass

      • Direct media through SBC
      • Teams user must have access to the Public IP of the SBC

    • Local Media Optimization

      • Advanced Media Optimization
      • Granular call flows
      • Local information service
      • Location based routing

    • Diagrams

Implement SIP Trunking with Direct Routing​

  • Overview
    • Implement SIP Trunking with Direct Routing
    • Configuration Objects for Direct Routing
    • How to Configure and Connect a Session Border Controller
    • Test Direct Routing Connections
  • Configuration Required for Direct Routing
    • Connect the SBC with Microsoft Phone System
    • Enable Users for Direct Routing
    • Call Routing
  • Enable Users for Direct Routing
    • Teams license
    • M365 Phone System
    • Assign Phone Number
  • Types of Phone Numbers
    • User Phone Number
      • For End Users DID
    • Service Numbers
      • Auto Attendants
      • Call queues
  • Call Routing Objects
    • PSTN Usage Records
      • Defines the type of a call, specify type or class - internal, local call, long distance or international call
      • You cant deny international call
      • Based on number patterns
      • Assigned to Voice Routes

Plan and Configure Direct Routing

  • Overview
    • Exend a Direct Routing Infrastructure
    • Location Based Routing
    • On-network conferencing
    • Gateway translation rules
    • Emergency calling policies for users by using a Teams emergency call routing policy
  • Location Based Routing
    • Toll Fraud
      • Illegal to bypass the Public Switched Telephone Network
      • Telecom industry in loss
      • Organization doing Toll fraud penalized
    • Outbound PSTN Calls Requirements for User
      • Network Site Enabled for LBR
        • Calls Egress through the corresponding gateway
      • Network Site not Enabled for LBR
        • Calls Egress through a gateway not enabled for LBR
    • Receive or Trans Call
      • Answering endpoint located in the same site as call ingresses through LBR gateway
      • Transfer PSTN calls to endpoint at same site as user who attempts transfer
      • Transfer user to PSTN, call must be transferred through LBR gateway at same site as initial caller
    • Overview
      • Admin associates IP subnet and PSTN gateway to network site
      • Location determined by IP subet at the time of PSTN call
      • A user clients located at different sites - routing separately based on endpoint location
      • LBR needs to be applied to
        • Users
        • Network sites
        • PSTN gateways
    • Apply LBR at the User Location

      • Only applies to users set up for Direct Routing

      • Users must be enabled for Location-based Routing if they are under toll bypass restriction

      • User enabled for Location-Based Routing an an LBR site, must call through a LBR gateway connected to the site

      • Routing is based on the users client site can be

        categorized

        in the following way:

        • User located at same LBR site associated to PSTN gateway where their DID (Direct Inward Dialing) is assigned
        • User located at a different LBR site not associated to PSTN gateway where their DID (Direct Inward Dialing) is iassigned
        • User located at an internal site that's not enabled for LBR
        • User located at an unknown site

      • Apply LBR at the network site

        • Enable LBR at network sites to determine gateways to route LBR enabled users when roaming
        • If user enabled for LBR roams to LBR site, only LBR PSTN gateway enabled at that site can be used for outbound calls
        • If LBR user roams to non-LBR site, any non-LBR gateway can be used for outbound calls

      • Apply LBR at the PSTN Gateway

        • Gateways are associated to site to determine a user who is enabled for LBR can be located for PSTN calls
        • Gateways must be enabled for LBR to ensure that it´s under toll bypass restrictions and can´t be used by users who aren´t enabled for LBR
        • The same gateway may be assocaited to multiple sites and it can be configured to be enabled for LBR or not enabled for LBR, depending on the site
  • On-network Conferencing
    • Prerequisites
      • Ensure all users for audio conferencing are using Teams for all meetings
      • Assign audio conferencing licenses to all users who will be using on-network conferencing
      • Set up the audio conferencing service
      • Set up your SBC for direct-routing
    • Enable Dial-In Calls Routing for Microsoft Audio Conferencing through Direct Routing
      • To route dial-in calls made by on-premises users to the audio conferencing service through direct routing, configure routing rules for SBCs and PBXs
      • Configure telephony equipment of sites to route calls to any service number of the conference bridge of the organization through a direct routing trunk
      • You can find the service numbers in Teams admin center under Meeting - Conferencing Bridges
  • Gateway Translation Rules
    • Change the number, for outbound, and/or inbound calls, based on the number patterns
    • The policy applied at the SBC gateway level
    • Assign multiple translation rules to an SBC, applied in the order they appear when listed in PowerShell
    • Change the order of the rules in the policy
    • Number Translation Rules Policy
      • Can be used to translate the numbers of following calls
        • Inbound Calls
          • Calls from a PSTN endpoint to a Teams client
        • Outbound Calls
          • Calls from a Teams client to a PSTN endpoint
        • PowerShell
          • New-CsTeamsTranslationRule
          • Set-CsTeamsTranslationRule
          • Get-CsTeamsTranslationRule
          • Remove-CsTeamsTranslationRule
          • Set Translation rule to Gateway with either
            • New-CSOnlinePSTNGateway
            • Set-CSOnlinePSTNGateway
  • Emergency Call Routing Policy
    • Enhanced emergency services enabled for users
    • Numbers used to call emergency services
    • How calls to emergency services are routed
    • Apply only to Direct Routing. Not to Calling Plans or Operator Connect.
    • Emergecy Calling Policy Assignment can be done to
      • Users
        • Automatically Global policy or assigned custom policies
      • Network Sites
        • Create and assign custom policies
        • Overrides the user policy
    • How to assign a custom emenergency call routing policy to
      • Users
        • Directly to user
        • Batch assignment - if supported by policy type
        • Group assignment - if supported by policy type
      • Network sites
        • Set-CSTenantNetworkSite -Identity -EmergencyCallRoutingPolicy

Deploy and Maintain a Survivable Branch Appliance

  • Overview
    • SBA and its prerquisites
    • Maintenance and updates for SBA and SBC
    • Configure SBA policies to users
  • Survivable Branch Appliance SBA for Direct Routing
    • WAN outage - no connection to Microsoft Phone System
    • SBC connected through Local Area Network
    • SBC connected to the PSTN for inbound/outbound calls
  • Prerequisites for SBA
    • Supported SBA
    • Media bypass on SBC configured
    • TLS1.2 enabled on SBA
    • Ports 3443, 4444 and 8443 for Teams Client
    • Port 5061 for SBC
    • UDP Port 123 for NTP server
    • Port 443 for Microsoft 365
    • Supported Teams Clients
      • Teams for Windows Desktop
      • Teams for macOS desktop
      • Teams for mobile
      • Teams phones
  • SBA Functionality
    • During internet outage, Teams client switches to SBA automatically, ongoing calls continues, with no interruptions
    • No action required from users
    • Client falls back to normal operation mode and connect to other Teams services
    • SBA uploads collected Call Data Records to cloud and call history will be updated
  • Calling related functionality in Offline Mode
    • Making PSTN calls via local SBA/SBC with media flowing through the SBC
    • Receiving PSTN calls via local SBA/SBC with media flowing through the SBC
    • Hold and resume of PSTN calls
  • Configuration steps to assign Users/Sites a SBA
    • Only possible with PowerShell
    • Create the SBAs
    • Create the Teams branch survivability policy
    • Assign the policy to the users
    • Register an application for the SBA with AAD
      • Read required data from M365
      • Only one AAD application needed for all SBAs
    • Steps to register
      • Reigster the application
      • Set the implicit grant token
      • Set the API permissions
      • Create the client secret
    • PowerShell
      • New-CSTeamsSurvivableBranchAppliance
      • New-CsTeamsSurvivableBranchAppliancePolicy
        • Creates a policy for an appliance
      • Set-CsTeamsSurvivableBranchAppliancePolicy
      • Grant-CsTeamsSurvivableBranchAppliancePolicy
        • Assigns user to Policy
  • Session Border Controller configuration and support for SBA
    • Each Vendors documentation is important
    • Deployment Options
      • Hardware or software based SBA
      • Can be installed on a virtual machine
      • Can be enabled on same SBC or as a separate device
    • SBA Calling Features
      • Teams to Teams and PSTN Calls
      • Teams to PSTN calls only (Some devices)
    • SBA Advance Calling Features not supported
      • Call forwarding delegation
      • Call queues
      • Call group
      • Music on hold
    • Known Issues with SBA
      • New SBA may take some time before used by SBA policies
      • After SBA policy assigned, may take some time before SBA is shown in Get-CsOnlineUser
      • Reverse number lookup against Azure AD Contacts is not done
      • Call forwarding settings does not work