1 Activities of LEARN: Introduction of VoIP services using Open Source Software Nimal Ratnayake Technical Manager, Lanka Educational and Research Network (LEARN) Senior Lecturer, Department of Electrical & Electronic Engineering, University of Peradeniya

2 Introduction LEARN: Lanka Educational and Research Network Interconnecting academic/research institutions within Sri Lanka Established in 1990 Currently interconnects –11 universities (some with multiple campuses) –National Science Foundation –University Grants Commission

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4 LEARN Services Internet Services –Two links to local ISPs –Bandwidth management using squid proxy –Some universities have their own links to ISPs Electronic Mail Services –Incoming/outgoing mail relay for universities –Virus/Spam filtering using AmaViS/SpamAssassin –Virtual hosting and POP/IMAP based mail services for individuals/organizations

5 LEARN Services (2) Training programs/Workshops –For technical staff conducted by local resource persons –For technical staff conducted by foreign resource persons with funding from Sida –International events such as NetSA Consulting –Networking

6 Developments Currently under the UGC –LEARN is a non existent entity: delays in universities paying their bills Reorganization (under discussion) –Non profit organization –Membership levels: Full member, Affiliate –Minimum core staff: 3 Engineering, 2 other –Annual membership fee + Internet access costs –Organizational structure: Management committee, Technical committee

7 New applications Many universities still see LEARN only as an ISP –Utilization of the network for inter university educational/research activities is very low New applications –Remote teaching/learning –Voice over IP –Video conferencing –Multicasting of special events

8 Voice over IP Roadmap –Use for communication among network engineers at member institutions and Technical Manager –SIP proxy/registrar servers at each university –Introduction of the services within and between campuses –Gateways to campus PBXs and PSTN

9 Software used Sip Express Router (SER) –Version running on a Linux box (RedHat 8.0 with kernel ) –Written in C, modular –We use proxy and registrar/location server –Also use MySQL module for interacting with user database –HTTP Authentication

10 User agents Used several user agents –Kphone (Version 3.11 running on Linux) –Ubiquity/Helmsman (Version running on windows) –MSN Messenger –SipC Interoperability of UAs satisfactory Noticeable echo in some situations Latency variations during session

11 Authentication HTTP digest authentication (RFC 2617) –Authenticator needs to know the cleartext password –Implications: Unix passwords, LDAP etc cannot be used –Currently we keep the cleartext password in MySQL database –Alternative authentication schemes is a research topic

12 Gateways SipRG: SIP Residential Gateway –Written in C++, somewhat bulky –Supports QuickNet telephone interface cards Open H.323 gateway –Supports the Voicetronix cards –SIP/H.323 translation required Cisco proprietary solutions –Currently the most widely used option –Requires some of our routers to be upgraded