© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v VoIP Signaling and Call Control Configuring SIP
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v Outline Overview Session Initiation Protocol Components of SIP SIP Messages SIP Addressing Call Setup Models Robust Design Cisco Implementation of SIP Configuring SIP on a Cisco Router Monitoring and Troubleshooting Summary Lesson Self-Check
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v SIP and Associated Standards SIP is a simple extensible protocol. SIP is defined in IETF RFC 2543; RFC SIP creates, modifies, and terminates multimedia sessions with one or more participants. SIP leverages various IETF standards: RTP, Real-Time Transport Control Protocol (RTCP), HTTP, SDP, DNS, SAP, and Real Time Streaming Protocol (RTSP). SIP performs addressing by E.164, , or DNS service record. SIP is ASCII text-based for easy implementation and debugging.
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v Functional Components
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v SIP Messages
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v SIP Request Messages INVITE: Indicates that a user or service is being invited to participate in a call session ACK: Confirms that a client has received a final response to an INVITE request BYE: Terminates an existing call; can be sent by either UA CANCEL: Cancels pending searches; does not terminate calls that have been accepted OPTIONS: Queries the capabilities of servers REGISTER: Registers the UA with the registrar server of a domain
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v SIP Response Messages 1xx: Informational response 2xx: Successful response 3xx: Redirection response 4xx: Client error response 5xx: Server error response 6xx: Global failure response
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v Addresses Fully qualified domain names E.164 addresses user=phone Mixed addresses –sip: ;
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v Address Registration
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v Address Resolution
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v Direct Call Setup
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v Call Setup Using a Proxy Server
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v Call Setup Using a Redirect Server
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v Survivability Strategies
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v Cisco Implementation of SIP
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v SIP User Agent
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v SIP Dial Peers
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v Example: show Commands
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v Summary SIP uses IETF protocols, including URL, DNS, and TRIP to define aspects of VoIP and multimedia sessions. The two basic components of SIP are UAs and network servers. SIP uses a request/response messaging model for communication. All messages are text-based and modeled on the HTTP syntax. SIP addresses follow the format and structure of a URL. Network components such as location and registrar servers record addresses and perform address resolution.
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v Summary (Cont.) Call setup between UAs is possible, but a proxy or redirect server may be used for scalability or to simplify UA configuration. Multiple SIP proxy or redirect servers enhance reliability. Cisco supports standalone clients and gateway clients. Support for SIP proxy or redirect services is provided by the Cisco SIP Proxy Server. The sip-ua command can be used to configure SIP on a Cisco router. Several show and debug commands help in monitoring and troubleshooting SIP.
© 2006 Cisco Systems, Inc. All rights reserved. CVOICE v