Cisco Systems OL-14619-01 manual Integrating by Using SIP

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Chapter 6 Integrating Cisco Unity with the Phone System

Integrating by Using SIP

Integrating Cisco Unity with Cisco Unified Communications Manager Express in SRST Mode

Cisco Unity supports a topology with centralized call processing and distributed messaging, in which your Cisco Unity server is located at a remote site or branch office and registered with the Cisco Unified CM at a central site.

When the WAN link fails, the phones fall back to the Cisco Unified CM Express-as-SRST device. Cisco Unity can also fall back to the Cisco Unified CM Express-as-SRST device, which lets users at the remote site access their voice messages and see message waiting indicators (MWIs) during a WAN outage. Note that MWIs must be resynchronized from the Cisco Unity server whenever a failover happens from Cisco Unified CM to Cisco Unified CM Express-as-SRST or vice versa.

For information on setting up this configuration, see the Integrating Cisco Unity with Cisco Unified CME-as-SRSTapplication note at http://www.cisco.com/en/US/products/sw/voicesw/ps4625/prod_troubleshooting_guides_list.html.

Integrating by Using SIP

SIP (Session Initiation Protocol) is the Internet Engineering Task Force standard for multimedia calls over IP. SIP is a peer-to-peer, ASCII-based protocol that uses requests and responses to establish, maintain, and terminate calls (or sessions) between two or more end points. A SIP network uses the following components:

SIP proxy server

The proxy server is an intermediate device that receives SIP requests from a client

 

and then forwards the requests on behalf of the client. Proxy servers receive SIP

 

messages and forward them to the next SIP server in the network. Proxy servers can

 

provide functions such as authentication, authorization, network access control,

 

routing, reliable request retransmission, and security.

 

 

Redirect server

Provides information to the client about the next hop or hops that a message should

 

take. The client then contacts the next hop server or user-agent server directly.

 

 

Registrar server

Processes requests from user agent clients for registration of their current location.

 

Registrar servers are often installed on the redirect or proxy server.

 

 

Phones

Can act as either a server or client. Softphones (PCs that have phone capabilities

 

installed) and Cisco SIP IP phones can initiate SIP requests and respond to requests.

 

 

Gateways

Provide call control. Gateways provide many services; the most common is a

 

translation function between SIP call endpoints and other terminal types. This

 

function includes translation between transmission formats and between

 

communications procedures. In addition, the gateway translates between audio and

 

video codecs, and performs call setup and clearing on both the LAN side and the

 

switched-circuit network side.

 

 

Cisco Unity accepts calls from a proxy server. Cisco Unity relies on a proxy server or call agent to authenticate calls.

SIP uses a request/response method to establish communications between various components in the network and to ultimately establish a conference (call or session) between two or more endpoints. A single call may involve several clients and servers.

Users in a SIP network are identified by:

•A unique phone or extension number.

 

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Contents Design Guide for Cisco Unity Americas HeadquartersDesign Guide for Cisco Unity Release N T E N T S Workstations Authentication Centralized Voice Messaging Configuration Viii Audience Document ConventionsSupport Policy for Optional Third-Party Software Cisco Product Security Overview Xii Product Area Design or Feature Documentation Design Guide OverviewDesign Guide for Cisco Unity Bridge at Page Design Guide Overview Design Guide for Cisco Unity Release Cisco Unity Concepts How Cisco Unity WorksUnified Messaging Voice MessagingHardware Components of a Cisco Unity System One or More Cisco Unity Servers Cisco Unity Supported Platforms List atNetwork Connection Optional for Some Configurations Voice Messages Are Stored in Domino or Exchange Where Cisco Unity Stores DataSoftware Components of a Cisco Unity System DominoExchange Enabling Cisco Unity Servers to Communicate with One Another Networking Guide for Cisco Unity at Some Configuration Settings Are Stored in the Registry Name Resolution Availability of Network ResourcesDomain Controller Access and Availability Availability of Message Store ServersUsing Firewalls with Cisco Unity Sizing and Scaling Cisco Unity ServersStorage Capacity for Voice Messages Number of Voice PortsAudio Codecs How Codecs Affect the File Size of Voice MessagesAudio Codec TTS, TTY, Pocket PCs, and Hand-Held ComputersInteroperability Among Multiple Voice-Messaging Systems Quality RatingDeployment Models Unified Messaging with Customer-Provided Infrastructure Voice Messaging with Customer-Provided Infrastructure Multi-Site WAN with Distributed MessagingPhysical Placement and Network Infrastructure Considerations for Customer-Provided Infrastructure Active Directory ConsiderationsDesign Guide for Cisco Unity Release Exchange Considerations All Versions Exchange Considerations That Apply Only Exchange Considerations for Cisco-Provided, Dedicated Infrastructure OL-14619-01 Overview of Cisco Unity with Domino and Notes Maximum Number of Cisco Unity Subscribers Domino Address Book TerminologyChanges That csAdmin Makes to the Domino Address Book Element NameChanges That csClient Makes to the Mail File Server Placement Windows Domains and Domino DomainsAuthentication Active Directory Accounts and PermissionsDomino Permissions Cisco Unity Subscribers and Domino UsersDomino Clusters Message Routing Client Access LicensesCisco Unity and the Domino Address Book Backing Up and Restoring DataUnified Messaging Configurations Unified Messaging, No Domino ClusterServers Requirements and Recommendations Voice Messaging Configuration Criteria for a Supported ConfigurationUnified Messaging, Domino Cluster Deploying Cisco Unity for Lotus Domino Deployment Tasks for Unified Messaging Configurations Administrative Access and ControlNetwork Services Establishing Support PoliciesOperational Tasks Design Guide for Cisco Unity Release Integrating Cisco Unity with the Phone System OverviewHow an Integration Works Lines and Cables to Make Physical Connections Integration with Cisco Unified Communications ManagerDigital Integration with Digital Pimg Units Dtmf Integration with Analog Pimg Units Timg Integration LAN/WANDtmf Integration with Voice Cards Serial Integration with Voice CardsSettings in the Phone System and in Cisco Unity Connections for a Serial Integration by Using Voice CardsCall Control General Integration Issues Feature Sccp SIPIntegrating Cisco Unity with the Phone System Option Considerations Cisco Unified Communications Manager Security Features DescriptionDescription When Data Is Encrypted Setting EffectSettings for Individual Voice Messaging Ports Disabling and Re-Enabling SecurityPacketization Sccp Integrations Only Sccp SIP Cisco 11 Cisco Unified Communications Manager Fallback with Pstn Cisco Unity to a branch office will fail Integrating by Using SIP Supported SIP Integrations Cisco Unity Failover with SIP TrunksSIP Compliance Description of Pimg Integrations Dtmf Integration with Analog Pimg Units Description of Timg Integrations Setup and Configuration Firmware Updates Serial IntegrationsIncreasing Port Capacity Cisco Unity FailoverCisco Unity Failback Multiple Integration Support/Branch Office ConsolidationIntegrating with Multiple Phone Systems Using Sccp Phone Systems with Other Integrations Requirements for Integrations with Multiple Phone SystemsReasons to Use Alternate Extensions Optional Integration FeaturesAlternate Extensions How Alternate Extensions WorkAlternate MWIs MWIs for Extensions on a Non-Integrated Phone SystemCentralized Voice Messaging OL-14619-01 OL-14619-01 Cisco Unity Failover and Standby Redundancy FailoverStandby Redundancy Cisco Unity Failover and Standby Redundancy Cisco Unity Failover and Standby Redundancy Diagram of a Standby Redundancy Configuration Pstn WANOL-14619-01 Voice-Recognition Access to Cisco Unity OL-14619-01 Migrating to Cisco Unity from Another Voice-Messaging System Migrating to Cisco Unity from Another Voice-Messaging System D E IN-2 IN-3 IN-4
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