Telecommunication Networks and Systems ATM, interfaces Krzysztof Wajda Department of Telecommunications, AGH-UST November, 2017
Outline Interfaces: functional description Interfaces: media and overhead considerations API for ATM
Lecture scope Concepts: UNI, NNI PNNI API description of interfaces in specific media solutions
ATM Interfaces
Interfaces physical layer (ATM Forum) Multimode fiber» 100 Mbps, coding 4B/5B» 155 Mbps, SONET STS -3c (SDH)» 155 Mbps, coding 8B/10B Singlemode fiber» 155 Mbps, SONET STS-3c (SDH)» 622 Mbps,» 2,488 Gbps shielded twisted pair» 155 Mbps, coding 8B/10B Coacial cable» 6.132 Mbps, J-2» 45 Mbpss, DS3 unshielded twisted pair» 52 Mbps, cat 3» 155 Mbps, cat 5» 1.5 Mbps, DS1
Interfaces physical layer (ATM Forum) Name Bitstream (Mbps) Effective bitstream (Mbps) SONET STS-1 51.84 49.536 SONET STS-3c 155.52 149.76 SONET STS-12c 622.08 594.432 SDH STM1 155.52 149.76 SDH STM4 622.08 594.432 DS-1 1.544 1.536 DS-2 6.312 6.176 DS-3 44.736 40.704 E1 2.048 1.92 E3 34.368 E4 139.264 multimode fiber (FDDI) STP 155.52 fiber link 100 100 155.52 UTP 51.84 25.60 12.96 149.536 149.536 23.18
Interfaces basic terminal interface UNI access to network interface NNI ATM UNI - User Network Interface NNI - Network Node Interface
Interfaces (ATM Forum) DXI Public UNI DTE (router) DCE (ATM DSU) Public ATM network B-ICI Private ATM network Public UNI Public ATM network B-ICI Public ATM network Private UNI Private NNI Public UNI ATM User ATM User Private ATM network
Interfaces UNI specification UNI 2.0 (June 1992, formal meaning), specification UNI 3.0 (September 1993, first stable version), specification UNI 3.1 (September 1994), specification UNI 4.0 (July 1996, practical implementations), specification UNI 4.1 (April 2002) defines standards for physical and link layers for ATM, for interworking of user and operator s access equipment określa standardy dla protokołów w warstwie fizycznej i warstwie ATM, UNI contains: physical layer interfaces, ATM layer functions, interface to management system sygnaling. terminal interface UNI access interface NNI ATM UNI - User Network Interface NNI - Network Node Interface
Interfaces P-NNI P-NNI: Private Network-Node Interface defines interface between Switching Systems (SS) signaling based on UNI defined: P-NNI Management and P-NNI Traffic Management oriented towards constructing scalable and heterogenous ATM networks (many vendors):»routing»adressing
PNNI specification PNNI 2.0 (April 2002), specification PNNI 1.1 (March 1996), PNNI is considered also for usage in modern optical networks (ASON, OTN), however support for O-PNNI (Optical PNNI) is lower than for CR-LDP or RSVP.
B-ICI B-ICI - Broadband Intercarrier Interface defines an interface between public networks many standards based on digital transport systems:» 44.736 Mbps, DS3» 155.52 Mbps, STS-3c» 622.08 Mbps, STS-12c defines support for services: SMDS, Frame Relay, Cell Relay, link emulation, recent idea of AINI (ATM Internetworking Interface)
DXI DXI - Data Exchange Interface defined for easy connection of standard (legacy) router to ATM networks between DTE i DCE defines protocols for physical and link layers defines local management interface and information database
Interface 155 Mbps SDH STM1/SONET STS3c 270 column 9 r o w s Maintenance and operations... 1 Synchronous Payload Envelope (1 column of overhead) 125 µsec 9 bajtów 9 261 8/125 µsec = 149.76 Mbit/s payload
Interface 2,048 Mbps E1 32 bytes/125 ms...... 0 1 2... 15 16 17... 31 bajty Framing and Overhead bytes Informationbytes 32 x 8/125ms = 2.048 Mbit/s Cell delineation using HEC mechanism
Interface 26,6 Mbps UTP3 Based on physical layer specification IEEE 802.5 with 4B/5B coding plus scrambling 32 Mbods x 4/5 = 25.6 Mbps Cell separation by double symbols x Cx cell or x 4 cell Reset Scramble No Scramble Reset
ATM-API API - Application Programming Interface API set of functions translating requirements of applications into AAL parameters API contains 3 interfaces:» ATM-UNI signalling»adaptation layers ATM-APIs for all versions of AAL» empty AAL for direct access
Summary Many versions of interfaces for all media and purposes Most popular are synchronous solutions An important issue is protocol overhead in some cases (e.g. if ATM works over a L1 protocol)
Bibliography ATM Forum standards ITU-T Recommendations D. Ginsburg, ATM. Solutions for enterprise networking, Addison-Wesley, 1999 Lecture notes: http://www.kt.agh.edu.pl/~wajda/students/telecommunication-networks-andsystems/
Thank you!