NET 3710 Signaling Signaling Functions Switch to switch

NET 3710 Signaling

Signaling Functions • Switch to switch communication • Switch to station communication – Supervising – Addressing – Alerting – Call Progress

Signaling Methods: In Band. . . • Loop-Start Signaling • Ground-Start Signaling • Wink Start

General Call-State Model: In-Band

Signaling Methods: Out-of-Band or Clear Channel. . . • ISDN – Primary Rate Interface (PRI) – Used for PBX and Business customers – Added features (CLID, RLT, etc. ) – Quicker call setup than in-band • System Signaling No. 7 (SS 7) – Used for PSTN Carrier Networks – Enables multiple network services

Signaling System 7 • Standard Method for Linking Central Offices • Supports CLASS Services • Required for: – Local Number Portability (LNP) – E 800 services – Calling Name/Number Delivery (CNAM) – Advanced Intelligent Networking (AIN)

Architecture of SS-7 SCP SP SP User STP SP SP STP SP User SP SP=Signal Point STP=Signal Transfer Point SCP=Service Control Point

Purposes of SS 7 • • Improves Call Management Enhances Network Management Separates Network Control From Hardware Supports User Database Handles Addressing And Supervision Supports 800 Number Portability Supports Local Number Portability

SS 7 Vs OSI

SS 7 Messaging • ISDN User Part – (ISUP) – Call Setup Messages • IAM, ACK, DIS, etc… • Transaction Capability User Part (TCAP) – Transports INAP messages • SCP Database queries – E 800, LNP, CNAM, etc.

SS 7 Signaling Examples • Call Setup – Global Title Translation – Point Code • CNUM/CNAM • E 800 • LNP

IP Signaling • IP traffic and PSTN traffic merging • Gateways required for conversion • Protocols – H. 323 – Media Gateway Control (Megaco) – SIP

H. 323 • Large, open, flexible protocol with many options (good/bad), somewhat proprietary though • H. 225 – call control – Session master/slave • H. 245 – multimedia control – Negotiates capabilities of endpoints (intelligent or dumb). • Gatekeeper – RAS – registration, admission, status • Uses Q. 931 messages (PSTN) over TCP/IP • Can be setup as peer to peer with intelligent endpoints

Media Gateway Control • Megaco and H. 248 • Controls interaction between Media Gateway and Media Gateway Controller (softswitch, ie. Gatekeeper in H. 323) • Call Control in central controller

SIP • • • Simple protocol for multimedia applications over IP Text messaging between endpoints Addresses are a URL Decentralized – intelligent endpoints Presence – Servers keep track of users status and availability, and where to be reached (Instant Messaging uses SIP) • Proxy server – routes information, locates users and stores their preferences • Uses other protocols – SAP, SDP, TRIP, RSVP, AAA

SIP Advantages • Operates over Any Network • Provides Expanded User Choices • Enables Developers to Create New Applications • Supports Multimedia • Allows User to Specify Best Way to Communicate

SIP Architecture

SIP Call Setup