1 © 2001, Cisco Systems, Inc. Technology Overview - Voice Gateway SS7 Interconnect for Voice Gateway Key Technologies for PS Project and Program Managers Created and Presented by Steve Wells

2 Technology Overview - Voice Gateway What’s an SS7 Voice Gateway? Why’s that important? What’s it all about? Challenges Concepts Components Layout SS7 Interconnect for Voice Gateway

3 Technology Overview - Voice Gateway The Changing World Telecommunications is undergoing rapid change. The infrastructure is Old World. The needs and opportunities are New World. POTS and PANS Plain Old Telephone Service Pretty Amazing New Services

4 Technology Overview - Voice Gateway Old World Infrastructure Voice network and data network on the same wires. Circuit switched lines. Voice traffic on voice lines. Packet data on voice lines. Optimized for voice. Voice calls average 6 minutes.

5 Technology Overview - Voice Gateway New World Challenges 1980’s and 90’s - traffic growth Voice grew linearly. Data grew exponentially. Now: data traffic = 5 × voice traffic. Data traffic: brief bursts, then quiet. Data on voice lines wastes bandwidth. Calls average 32 minutes.

6 Technology Overview - Voice Gateway New World Objectives Data on packet data lines. Voice as packet data (VoIP). Optimize for data. Statistical multiplexing provides efficient bandwidth use. Business Needs Consolidate 2 networks (voice and data) into 1. Provide access for data calls. Consumer Market Consolidate entertainment (TV), telephone, and Internet access into one communications network.

7 Technology Overview - Voice Gateway Switching Network Line Concentration Digital Trunk Subsystem Call Control Connection Control Features Common Channel Signaling Complex Administration Maintenance Billing TDM Switch by SNALE TDM Switch by SNALE Services Plane IN Service Logic AAA, Address Resolution Service Logic Open Packet Telephony SCP Partners VCO4K Unified Comm. VSC Signaling Controller Call Manager IN / AIN / CTI Call Control Plane Signaling and Call Control Service Access Function Switch-Based Service Logic End-to-End Voice Services Definition Conversion Simulator Configuration Analyzer Interworking Tool Set Call Logic Full Access to Existing and New IN/AIN Products Flat Efficient Transport Layer User Programmable Call Control Connection Plane Connection Negotiation Transcoding Bearer Switching Media Control: RTP, PNNI, Etc. Switching Logic MGCP / SIP / H.323

8 Technology Overview - Voice Gateway Signaling System 7 Out of Band Signaling More signal data at higher speeds. Signals sent anytime. Signals to network elements with no direct trunk connection. Circuit resources are not used until the connection can be completed.

9 Technology Overview - Voice Gateway Signaling System 7 Voice as Packet Data More voice data on fewer lines. Non-voice data can share the line. A voice packet can go down any trunk. No tying up dedicated switches to keep calls connected. Phones and calls with special features.

10 Technology Overview - Voice Gateway SS7 Architecture SSP Service Switch PointStarts/ends call Access end points and controls. Bridge unmated pairs. Cross to mate for reliability. Diagonal to another network. Extended to non-home pair. Fully associated Service Points. A-Links - F-Links PSTN SS7 Signaling Network BB BB BB F F EE AA A A A A AA AA D D D CCC C SSP STP SCP STP Signal Transfer PointRoutes call SCP Service Control Point“Specials” database

11 Technology Overview - Voice Gateway The technical challenges are immense. Voice over IP Performance must be great. Users will:  Demand a high Quality of Service.  Assume calls will stay connected.  Count on phones to work during power failures.  Hold fully duplex conversations.  Presume privacy and security.  Dial in to the Internet.  Send and receive Faxes.

12 Technology Overview - Voice Gateway Voice over IP Infrastructure Challenges Old wire. Existing electronics / hardware is getting old. Not state of the art. Tired and failure prone. Huge investment and effort needed to install new lines and equipment.

13 Technology Overview - Voice Gateway Voice over IP Security and Reliability Challenges Callers must send and receive only their own voice packets. DES Security -- Data Encryption Standard. IP phones must have battery backup, e.g. 4 hours. Low power consumption components for use while self-powered. Non-volatile memory to maintain phone functions.

14 Technology Overview - Voice Gateway Voice over IP Latency (Delay) Challenges  Accumulation Delay - to collect a frame of voice data.  Processing Delay - to convert a frame into packets.  Network Delay - to transmit packets across a network.  Polling Delay - till the head end asks for more packets.  Echo - must be cancelled with digital filtering.  Jitter - the packets don’t arrive at regular intervals if they’re even in the right order!  Lost packets - must be interpolated or packets must have redundancy. Voice packets can’t be resent a few seconds later like lost internet data. (Think about it.)

15 Technology Overview - Voice Gateway Voice over IP Phone Billing Challenges Billing is handled by software call agents, routing through a voice enabled cable modem, or a utility box Broadband Telephony Interface.  Recurring line charges.  Local, long distance, and international calls with varying rates based on day, time of day, and actual connect duration.  Per use charges: directory assistance or call return.  Special per minute services: C++ Programmers’ Psychic Hotline

16 Technology Overview - Voice Gateway What makes VoIP possible?  Digital Signal Processing (DSP) Hardware is incredibly fast and getting faster!  Talented engineers at Cisco are top 10% people! Voice over IP Fax Challenges  Precise timing is needed or the call will drop.  Lost data packets can drop the call, too. Nobody said VoIP telephony was easy!

17 Technology Overview - Voice Gateway Solution Components SLT AS5x00 Signaling Controller AKA: Cisco SC2200 Host Signaling Link Terminal AKA: SLT Cisco Voice Gateway Based on Sun Netra 1400s and 1800s Based on 2611 w/ Special Cisco IOS Image for the SLT Cisco IOS = 12.1(3)T Based on AS5300 w/ 12.1(2a)T2 or Later Supports over 60 Different ISUP Variants into Q.931+ over IP Supports Terminating A or F Links and Encapsulating MTP 3 Layers and above over IP; Provides Muxing F Links off E1s H.323 Voice-over-IP Media Gateway Responsible for Voice Packetization, H.323 Signaling DiagramDescriptionDetailsPurpose Cisco SC2200 Node Cisco SC2200 Host

18 Technology Overview - Voice Gateway Universal Access Servers Low End Mid RangeHigh End Density Cisco AS or 16 Async Ports Cisco AS5300 (Access Server) 4 or 8 T1/E1/PRI 192/240 Ports Analog/ISDN Cisco AS5800 (Access Server) 48 T1/E1/PRI or 2 CT3 Up to 1440 Ports Analog/ISDN Cisco AccessPath TS3 (Access Server) 168 T1/E1/PRI 4032/5040 Ports Analog/ISDN

19 Technology Overview - Voice Gateway CPE Software Features CPE Software Features PPP Multilink PPP extensions DIAL ACCESS Software Features DIAL ACCESS Software Features Integrated V.90 Modem & ISDN Support Dial Access Stacking Architecture (DASA) SS7 Integration AAA Support AAA Web Caching Via WCCP IGP Support/BGP Peering MPLS/Traffic Engineering IP QoS Support IGP Support/BGP Peering MPLS/Traffic Engineering QoS Support POP Software Features POP Software Features CORE Software Features CORE Software Features Dial Internet Access Software Features Dial Platform Cache Distribution Router Core Router IP Core PSTN Layer 2 Interconnect

20 Technology Overview - Voice Gateway SS7 Solutions Provide Opportunity for revenue sharing Service portfolio A new interface for access servers Allows selective acceptance of calls (white/black list screening) Target markets Lower interconnect and capital costs enable down-market expansion SS7 is often more readily available than PRI for faster time to market Geographic reach Certain countries require SS7 interconnect Network scale SS7 enables more revenue minutes per circuit (faster call setup time) Cisco SC2200 AS5X00 VoIP Network SS7 Network PSTN IMT SS7 Links