MIT SIP.edu Installation

MIT implemented SIP.edu on March 20, 2003. Over 12,000 mit.edu email addresses were mapped to PBX phone numbers in the initial installation. In December 2005 the the SIP infrastructure was migrated from Pingtel SIPxchange to OpenSER. Information on the original Pingtel implementation is here.

Installation Details

MIT is using OpenSER for its SIP proxies running on RedHat Linux Enterprise servers. Our implementation utilizes three functional types of SIP proxies.

Outgoing Proxy - provides authentication and authorization functions, and ensures preferred routing for MIT SIP clients. Redundancy is provided through an F5 load balancer.
Internal Proxy - provides connectivity to the PSTN gateway and ensures external SIP issues do not impact internal MIT SIP traffic and clients. Redundancy is provided through DNS SRV records.
DMZ Proxy - provides SIP connectivity to external clients outside of MIT, and provides isolation for internal MIT clients to ensure external anomalies do not affect internal MIT clients. Redundancy is provided through DNS SRV records.

Directory lookups are done from OpenSER to our LDAP directory running on OpenLDAP . MIT is currently using a Cisco 3825 gateway with two PRIs to our Lucent 5ESS PBX.

Our implementation also uses Asterisk for voice mail and voice mail to email forwarding; AG Projects Media Relay for NAT traversal; and FreeRADIUS .

MIT has developed web pages for configuration and feature activation for both users and administrators. These are built using Apache and Oracle and use X.509 certificates for authentication. A configuration server is used to configure hard phones "out of the box". Currently the line of Polycom SIP phones are supported for automatic configuration.

9/29/06 - dbaron@mit.edu