Signaling Blog

Skype has been down for well over 24 hours now. In the meantime I switched over to using GizmoProject - shame my contact list on Gizmo is so bare. For those who do not know, Gizmo is a Skype clone; it is powered by the same great Global IP Sound (GIPS) codec as well as also using a self-organising peer-to-peer (P2P) network to route the call signalling. It tries to differeniate itself by claiming to be based on completely open standards (e.g. it purports to use standard SIP, although I am unsure how the P2P element is then handled as it is not using any P2P SIP standard) unlike Skype which went for a blackbox approach. I’ve often had software crashes and other problems with Gizmo (C++ runtime errors etc.) plus I dislike the interface in comparison with that of Skype - let alone the fact that my buddy-list is well populated on Skype. Hence when Skype eventually works again, I will be switching back.

For those battling with the telecom vs Internet reliability dichotomy I’d like to throw in a point to reflect on. Signalling system #7 (SS7/C7) has had its degree of outages. See for example Aspects of Integrity in the NII , John C. McDonald ,MBX Inc. Quote:

“Several well-publicized SS7 outages occurred in 1990 and 1991 due to software bugs ^{[6, 7]}. The first had a nationwide impact and involved the loss of 65,000,000 calls. Others involved entire cities and affected 10,000,000 customers. In response to a massive outage in September 1991, the mayor of New York established a Task Force on Telecommunications Network Reliability. The task force noted that “the potential for telecommunications disasters is real, and losses in service can be devastating to the end user” ⁸.”

6 Fitzgerald, K. 1990. “Vulnerability Exposed in AT&T’s 9-Hour Glitch,” The Institute, March.

7 Andrews, E. 1991. “String of Phone Failures Reveals Computer Systems’ Vulnerability,” New York Times, July 3.

8 City of New York. 1992. “Mayor’s Task Force on Telecommunications Network Reliability,” January