Only Works Within Same Network (Score 2, Interesting)

If ISPs use QoS to give preferential treatment to their on VoIP services, they can only do so within their own network, as mentioned in the article. If best effort carriage under such conditions results in degrading all other VoIP traffic, then the whole scheme seems doomed to failure.

The special, high-quality calls promised you by ISPs engaging in this practice would revert to standard best effort calls the moment you reach out to touch someone who is using a different ISP. This scheme only supports high quality on something analogous to a local phone call. /jab