Ascend Communications

Ascend Communications - What They Do

Transcript

1. Ascend Communications Extending the Internet to Meet Your Needs
2. 2 What Is Internet Access? • The use of service provider offerings to establish a connection between a user’s location and the Internet • This may be either analog or digital • The traffic may be data, voice or fax • Access may be through an Internet service provider’s point of presence or a corporate gateway Internet Service Provider Telecommuter LAN Remote Office Customer Site LAN Carrier Services Internet
3. 3 Logical Networks Internet Access Site B Access Site A User Site A User Site B Telephony Network Internet A Virtual Private Network
4. 4 How Is the Internet Used Today? • Circuit switched access (analog, ISDN) • Data traffic • Corporate access through firewalls • Marketing based web sites • Concerns about access bandwidth and privacy • Accept what happens in the cloud
5. 5 Who Uses the Internet? Mobile Small Office Remote Office Corporate Enterprise Backbone ISP POP SOHO Traveller Video PBX LANS Video Phone Fax LAN PC Internet PC Phone PC Phone Fax PC LANS
6. 6 User/Access Sites Home Office (Single User) Applications •  Internet Access •  On-Line Services Access •  Telecommuting •  Shopping Access Lines •  Circuit Switched Traffic •  Data •  Voice •  Fax Phone Fax PC Phone
7. 7 Applications •  Internet Access •  Telecommuting •  Electronic Commerce •  Storefront Access Lines •  Circuit Switched Traffic •  Data •  Voice •  Fax User/Access Sites Small Office (Multiple Users) PC Phone PC PC LAN LAN
8. 8 User/Access Sites Remote Office (Multiple Users) Applications •  Internet Access •  Intranet/Extranet Access •  Corporate Access •  Telecommuting •  VideoConferencing Access Lines •  Circuit Switched •  Leased Traffic •  Data •  Voice •  Fax •  Video Video Phone Fax LAN PC
9. 9 User/Access Sites Corporate Enterprise Video PBX Applications •  Internet Access •  Corporate Communication •  Intranet/Extranet Access •  Telecommuting •  VideoConferencing •  Electronic Commerce •  Virtual Private Network Access Lines •  Circuit Switched •  Leased Traffic •  Data •  Voice • Fax • Video Video PBX LAN LAN PC
10. 10 User/Access Sites Corporate Backbone Network Application •  Internet Access •  Intranet/Extranet Access •  Network Management •  Virtual Private Network Access Lines •  Leased Traffic •  Data •  Voice •  Fax •  Video Internet
11. 11 User/Access Sites ISP POP Applications •  Internet Access •  Network Management •  Web Site •  Security •  Virtual Private Network •  Wholesaling Access Lines •  Circuit Switched •  Leased Traffic •  Data •  Voice •  Fax •  Video Internet Internet
12. 12 User/Access Sites Mobile (Single User) Hotel Access Cell Phone Access Applications •  Internet Access •  Telecommuting Access Lines •  Circuit Switched Traffic •  Data •  Voice
13. 13 Where Are We Going? Public Switched Public Internet Telephone Network Protocol Network Designed a Century Ago Designed for Modern High-speed for Analog Voice Digital Communications Circuit-oriented Packet/cell/frame-oriented Point-to-Point Only Point-to-Point Any-to-Any Any-to-Many “Constant Bit Rate” Only Constant, Variable and Available Bit Rates 64 Kbps Channels Only Virtually Unlimited Bandwidth Complex Layer-1 Signaling Simple Layer-2,3 Switching/Routing Difficult and Expensive to Scale Scales Easily and Affordably Limited “Add-on” Management Management Features Built-in
14. 14 How Much Network Bandwidth Is There? Copper (Electrical) DS0 64 Kbps DS1 1.54 Mbps (24 DS0s) DS3 43 Mbps (28 DS1s) Fiber (Optical) OC-1 50 Mbps OC-3 155 Mbps (3 OC-1s) OC-12 622 Mbps (4 OC-3s) OC-48 2.5 Gbps (4 OC-12s)
15. 15 Physical Network = Switch = Network Trunk = Access Line = User Site
16. 16 Virtual Private Network VPN 1 VPN 4 VPN 3 VPN 2 PHYSICAL LOGICAL The Physical Network Topology
17. 17 Network Trunks (T1) •  Key point: The network is a fabric of 64 Kbps threads (DS0s), originally designed to carry digital voice On a DS1 trunk, 24 64 Kbps channels are time division multiplexed into one 1536 Kbps circuit One DS1 Circuit 24 channels 1 2 3 4 5 6 7 8 23 22 23 24 1 2 3 21 24 One DS1 frame (1536 Kbps)
18. 18 Leased Line Traffic (Point to Point Circuit) One or more channels from origin to destination dedicated full-time to the user User Access Line (Local Loop) Access Equipment Central Site Access Line (Local Loop) Access Equipment Central Office Central Office
19. 19 Circuit Switched Traffic (Time Division Multiplexed Bandwidth) a.k.a. Public Switched Telephone Network (PSTN) One or more channels from origin to destination dedicated to the user for the length of the call PSTN User Access Line (Local Loop) Access Equipment Central Site Access Line (Local Loop) Access Equipment Central Office Central Office
20. 20 Central Office Circuit Switch Access Lines Network Trunks Service Provider Networks MDF = Main Distribution Frame 2 Wire 4 Wire 6 Wire Point-to-Point Circuit Circuit-Switched Trunk MDF Users
21. 21 Circuit Switched Access •  One 3.4 kHz channel •  Up to 33.6 Kbps data using symmetric modem •  Up to 56 Kbps data using asymmetric modem •  In-band signaling (DTMF) Analog 2 wire Access Equipment PSTN Central Office
22. 22 Circuit Switched Access •  Two 64 Kbps data channels •  One 16 Kbps out-of-band signaling channel •  ISDN “U” (2 wire) or “S/T” (4 wire) interface ISDN BRI U or S/T interface Access Equipment B2 D B1 One Circuit BRI PSTN Central Office D D D BRI frame B1 B2 B2 B1 B2 B1
23. 23 Circuit Switched Access •  24 56 Kbps data channels, 56 Kbps •  In-band signaling T1 Access Line 4 wire Access Equipment One T1 frame (1536 Kbps) 1 2 3 4 5 6 7 8 23 22 23 24 1 2 3 21 24 One T1 Circuit 24 channels PSTN Central Office
24. 24 Circuit Switched Access •  23 64 Kbps data channels •  One 64 Kbps out-of-band signaling PRI Access Line 4 wire 23 B channels D channel One PRI Circuit One PRI frame (1536 Kbps) 1 2 3 4 5 6 7 8 23 22 23 1 2 3 21 D D PSTN Central Office Access Equipment
25. 25 Central Site Remote User MP (a.k.a. ML-PPP) Multiple analog lines, switched 56 circuits, ISDN B-channels, etc... MP Datastream •  Multilink Protocol (RFC 1717) •  Inverse multiplexes multiple circuits to provide greater bandwidth •  Does not specify how circuits are established, controlled or managed
26. 26 Central Site Remote User Bandwidth Allocation Control Protocol (BACP) •  Adds control channel and intelligent dialing •  Both ends communicate during session •  Allows the dynamic allocation of bandwidth •  Open specification allows interoperability among multiple vendors’ equipment End-to-end communications channel to control all circuits used by MP Multiple analog lines, switched 56 circuits, ISDN B-channels, etc... MP Datastream
27. 27 Circuit Switched Access with External WAN Interfaces Access Server LAN Analog Modem Users Digital ISDN BRI Users Dial-Up Services Multiple Digital Access Lines Multiple Analog Access Lines TA or DSU Modem Digital Calls Multiple Serial Ports Analog Calls Protocol Processing
28. 28 Circuit Switched Access with Integrated WAN Interfaces Analog Modem Users Digital ISDN BRI Users Dial-Up Services 100% Digital Access (ISDN PRI, T1 or E1) Integrated TAs and DSUs Integrated Digital Modems Protocol Processing Access Server Analog Calls Digital Calls LAN
29. 29 Today’s Circuit Switched/Leased Point-to-Point Connections to the Internet Protocol (IP) Based Internet The Internet Leased or Circuit Switched Circuit Switched Circuit Switched Circuit Switched ISP ISP ISP ISP Corporate Location Remote Office Leased Mobile Travelers Customer/ Supplier Telecommuter
30. 30 What Is Internet Protocol? A packet switched network protocol with reliable (TCP) or unreliable (UDP) choices to support traffic Layer/Function APPLICATION Using Data TRANSPORT Directing Data NETWORK Moving Data LINK Physical Connection File Transfer Protocol (FTP), Simple Mail Transfer Protocol (SMTP), Simple Network Management Protocol (SNMP) Transmission Control Protocol (TCP), User Datagram Protocol (UDP) Ethernet, Token Ring, Frame Relay, Point-to-Point Protocol Protocols/Standards Internet Protocol (IP)
31. 31 IP Based Internet Uses Packet Switched Traffic (Statistically Multiplexed Bandwidth) A packet protocol over fixed bandwidth circuits that can be shared by multiple users data data data data data data data data data Digital Circuit examined by switch F L A G address data frame check sequence F L A G examined by switch
32. 32 Packet Network Virtual Circuits Frame Relay or ATM Virtual Circuit • Provides connectivity between locations Switched Virtual Circuit • Dynamically established when needed • Released when not needed Permanent Virtual Circuit • Statically defined at configuration • Always configured (active or idle)
33. 33 Quality of Service (QoS) Classes Frame Relay or ATM •  Class A: Constant Bit Rate – CBR –  Circuit transport – Continuous bit stream for video and digital voice, requires very low cell delay •  Class B: Variable Bit Rate – Real Time – rt-VBR –  Video conferencing – Packet video, delay sensitive applications, requiring low cell delay •  Class C: Variable Bit Rate – Non Real Time – nrt-VBR –  Video playback – Long bursty data or short bursty LAN traffic, some cell loss OK •  Class D: Available Bit Rate/Unspecified Bit Rate – ABR/UBR –  Computer data – LAN traffic
34. 34 Packet Switched Access Digital Subscriber Line (xDSL) •  DSL Technologies –  IDSL –  HDSL –  SDSL –  ADSL-CAP, ADSL-DMT •  High bandwidth over existing “local loop” twisted pair of wire Access Equipment Access Line (Local Loop) Central Office User Packet Network
35. 35 xDSL Access Options Central Office SOHO Copper Loops Any ISDN CPE SOHO SOHO Ethernet Ethernet Ethernet IDSL Up to 128 Kbps SDSL Up to 768 Kbps ADSL/Data w/POTS Up to 7 Mbps POTS Splitter PSTN Packet Network CO Circuit Switch DSL Access Module MDF
36. 36 Packet Switched Access ISDN Digital Subscriber Line (IDSL) •  IDSL – Technological innovation from Ascend •  128 Kbps symmetric data rate •  Single pair local loop to 18,000 ft. •  Compatible with any ISDN BRI TA, bridge or router •  2B1Q line code for transparent operation data data Access Equipment Packet Network IDSL 2 Wire data data Central Office
37. 37 Packet Switched Access ISDN Digital Subscriber Line (IDSL) Voice and Data Telephone Company Central Office 2-Wire Local Loop CO Circuit Switch Customer Premises T1 or T1/PRI Packet Network (IP, ATM, Frame Relay) PSTN