Ensuring access to emergency services in the presence of long internet dial-up calls

V. Ramaswami, David Poole, Soohan Ahn, Simon Byers, Alan Kaplan

Research output: Contribution to journalReview articlepeer-review

4 Scopus citations


Telephone availability is critical, particularly in emergency situations when people need immediate help. We used statistical data analysis and queueing models to identify the root cause of dial-tone unavailability in parts of the AT&T network and to develop remedies. Our solutions restored quality service, protecting the AT&T brand name and ensuring the safety of our customers. This work also gave AT&T opportunities to reduce transit charges paid to other carriers by $15 million per year. In addition, we have filed five patent requests, of which two have been granted and the rest are pending (Chaudhury et al. 2004, Kaplan and Ramaswami 2004). Furthermore, our findings have important implications for several current areas of research related to Internet and broadband technologies, call-center engineering, and network security.

Original languageEnglish
Pages (from-to)411-422
Number of pages12
Issue number5
StatePublished - Sep 2005


  • Capacity expansion
  • Communications
  • Equipment planning
  • Facilities
  • Industries


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