While it's nice having lots of routes listed in our zone, there are numerous routes weren't setup correctly or are no longer valid. This can be because of VSPs no longer allowing anonymous calls, incorrectly configured servers, configuration changes and so on and so forth. All these problems can lead to a lag in call setup times and other kinds of surprises that shouldn't happen in a real time environment demanded by VoIP calls. So with that in mind we (e164.org) have started working on methods to probe a every SIP URI in the database to see if "calls" will be accepted or not. At this stage we are monitoring the results from running a probe over SIP routes stored in our database. We haven't come to a conclusion in terms of a policy for failed routes, but we feel that sending people a warning email should be done at the very minimum. We are still debating about when and what circumstances dead routes should be removed. While we'd like to have probes for all protocols at this stage it isn't feasible (both coding and maintaining) so we encourage everyone to use SIP at the minimum for inter-connections as SIP routes will soon have a level of vetting. SIP is also the most widely supported open protocol on the internet so it makes sense to get everyone to use a common method of communication (even if people list additional protocols as well).