VoIP Signaling and Call Control

VoIP Signaling and Call Control Cisco Networking Academy Program 1

Need for Signaling and Call Control 2

Model for VoIP Signaling and Call Control VoIP signaling components Endpoints Common control Common control components Call administration Accounting 3

Call Control Models H.323 SIP MGCP H.248/Megaco protocol SAP RTSP Cisco CallManager 4

Translation Between Signaling and Call Control 5

RTP Sessions 6

Call Feature Negotiation 7

Call Administration and Accounting Administration Monitors call activity Monitors resource utilization Supports user service requests Accounting Maintains call detail records 8

Call Status 9

Address Registration 10

Address Resolution 11

Admission Control 12

Centralized Call Control 13

Distributed Call Control 14

Centralized Call Control vs. Distributed Call Control 15

Configuring H.323 16

H.323 and Associated Recommendations 17

H.323 Adapted to IP 18

H.323 Terminals 19

H.323 Gateways 20

IP-to-IP Gateways 21

H.323 Gatekeepers 22

Multipoint Conference Components 23

Component Relationships for Call Establishment and Management Endpoint (gateway) to endpoint (gateway) Endpoint (gateway) to gatekeeper Gatekeeper to gatekeeper 24

RAS Messages 25

H.323 Basic Call Setup 26

H.323 Fast Connect Call Setup 27

Finding and Registering with a Gatekeeper 28

Call Flow with a Gatekeeper 29

Gatekeeper-Routed Call Signaling 30

Multipoint Conferences 31

Scalability with Multiple Gatekeepers 32

Call Flow with Multiple Gatekeepers 33

Survivability Strategies H.323 replication strategies include the following: HSRP Gateway preconfigured for two gatekeepers or for multicast discovery Multiple gatekeepers configured for the same prefix Multiple gateways configured for the same prefix 34

H.323 Proxy Server 35

Cisco Implementation of H.323 36

Configuration Example 37

Configuring the Gateways Gateway 1 38

Configuring the Gateways (Cont.) Gateway 2 39

Configuring the Gatekeepers Gatekeeper 1 40

Configuring the Gatekeepers (Cont.) Gatekeeper 2 41

Example: show Command 42

Configuring MGCP 43

MGCP and Associated Standards MGCP is defined in RFC 2705, October 1999 MGCP architecture and requirements are defined in RFC 2805, April 2000 Centralized device control with simple endpoints for basic and enhanced telephony services Allows remote control of various devices Stimulus protocol Endpoints and gateways cannot function alone Uses IETF SDP Addressing by E.164 telephone number 44

MGCP Components 45

Endpoints Eight types of endpoints are defined in RFC 2705: Digital channel Analog line Announcement server access point IVR access point Conference bridge access point Packet relay Wiretap access point ATM trunk side interface 46

Endpoint Identifiers 47

Gateways and Their Roles Trunk gateway SS7 ISUP Trunk gateway MF NAS Combined NAS/VoIP gateway Access gateway Residential gateway Announcement servers 48

Call Agents 49

Basic MGCP Concepts Calls and connections Events and signals Packages and digit maps 50

Calls and Connections 51

Multipoint Calls 52

Events and Signals Events: Continuity detection (as a result of a continuity test) Continuity tone DTMF digits Fax tones Hookflash Modem tones Off-hook transition On-hook transition 53

Events and Signals (Cont.) Signals: Answer tone Busy tone Call waiting tone Confirm tone Continuity test Continuity tone Dial tone Distinctive ringing (0 7) DTMF tones Intercept tone Network congestion tone Off-hook warning tone Preemption tone Ringback tone Ringing 54

Packages Basic packages (generic media, DTMF, MF, trunk, line, handset, RTP, NAS, announcement server, script) CAS packages (RFC 3064) Business telephone packages (RFC 3149) 55

Gateways and Their Packages 56

Digit Maps 57

Control Commands EndpointConfiguration (EPCF) NotificationRequest (RQNT) Notify (NTFY) CreateConnection (CRCX) ModifyConnection (MDCX) DeleteConnection (DLCX) AuditEndPoint (AUEP) AuditConnection (AUCX) RestartInProgress (RSIP) 58

Call Flows 59

Survivability Strategies 60

Cisco Implementation of MGCP 61

Understanding Basics of Cisco CallManager Basic CallManager Configuration for MGCP Gateway Support: 1. Create an MGCP Gateway 2. Configure the FX Ports 3. Test the Phones for Local Connectivity 62

Cisco CallManager Implementation and Call Flows Registration 63

Cisco Call Manager Implementation and Call Flows FXS Call Flow 64

Configuring an MGCP Residential Gateway ccm-manager mgcp! mgcp mgcp call-agent 172.20.5.20! voice-port 1/0/0! voice-port 1/0/1! dial-peer voice 1 pots application MGCPAPP port 1/0/0! dial-peer voice 2 pots application MGCPAPP port 1/0/1! 65

Configuring an MGCP Trunk Gateway! ccm-manager-mgcp mgcp 4000 mgcp call-agent 209.165.202.129 4000! controller T1 1/0 framing esf clock source internal ds0-group 1 timeslots 1-24 type none service mgcp! controller T1 1/1 framing esf clock source internal ds0-group 1 timeslots 1-24 type none service mgcp! voice-port 1/0:1! voice-port 1/1:1! 66

Example: show Command Router# show mgcp statistics UDP pkts rx 8, tx 9 Unrecognized rx pkts 0, MGCP message parsing errors 0 Duplicate MGCP ack tx 0, Invalid versions count 0 CreateConn rx 4, successful 0, failed 0 DeleteConn rx 2, successful 2, failed 0 ModifyConn rx 4, successful 4, failed 0 DeleteConn tx 0, successful 0, failed 0 NotifyRequest rx 0, successful 4, failed 0 AuditConnection rx 0, successful 0, failed 0 AuditEndpoint rx 0, successful 0, failed 0 RestartInProgress tx 1, successful 1, failed 0 Notify tx 0, successful 0, failed 0 ACK tx 8, NACK tx 0 ACK rx 0, NACK rx 0 IP address based Call Agents statistics: IP address 10.24.167.3, Total msg rx 8, successful 8, failed 0 67

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