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Published byCody Turner Modified over 9 years ago
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IP telephony in CESNET Sven Ubik ubik@cesnet.cz
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CESNET Association of universities and research institutes in Czech Republic Operates Czech NREN (CESNET2) 8 gigaPoPs
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Goals and input create VoIP testbed reduce telephone charges provide new services accessible to as much people as possible various PBXs (Ericsson, Siemens, Alcatel, …) mostly Cisco routers ~ 10 major locations, ~10 minor locations
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Design decisions Strategic: connecting PBXs, IP phones later standard PSTN numbering plan gateway to PSTN detailed accounting Technical: digital interfaces (ISBN PRI/BRI) Cisco voice gateways H.323 signalling no explicit QoS
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VoIP network
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Calling access prefix + standard PSTN number 94 069 6991699TU Prague TU Ostrava 48 41 22 768734TU Liberec CERN, Switzerland
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Measurement and accounting Using multiple accounting plans in parallel Several aggregation levels Listing of answered/unanswered/busy calls Open software Resilience to configuration changes Sven Ubik: „IP Telephony Accounting and WAN Deployment Experience“, IPTEL 2001, April 2001, Columbia University.
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Linux MySQL LDAP authorization Measurement and accounting
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PBX vs. IP phone Why PBX: PSTN phone on every desk simple and reliable easy authentication and accounting Why IP phone: no need for PBX new services „true“ convergence
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H.323 vs. SIP Why H.323: widely supported mostly works Why SIP: simpler, textual, easier to debug easier programming of new services
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What next, problems Connecting IP phones - authentication (LDAP ?) - numbering plan (organization-level prefix ?) - QoS in MANs, LANs IPTAv2 - graphical representation - PBX interface utilization - more information sources (GK, SIP server) International peerings - top-level GKs (one in Cesnet?) SIP clients - PBXs and SIP phones + SIP/H.323 GW http://www.cesnet.cz/english/project/iptelephony
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