What makes you think carriers need to do voice on layer 2? Latest router technology and
fat pipes make doing it on layer 3 a possibility.
Simple. ATM QoS is mature and works. IP QoS is still vaporware. You can't do carrier-grade VoIP today unless you have no congestion. Most carriers do have congestion on their data networks, and will need to have a QoS mechanism in place in order to do QoS. Given what Cisco has available today, I'd say "good luck".
Yes, new carriers such as QWEST have gobs and gobs of bandwidth, and are doing VoIP. But that is because they don't have to worry about congestion. QWEST is more the exception than the norm.
Paul Johnson's recent remarks about QWEST and AT&T kind of give me a chuckle. I like him, but I think he's wrong here. AT&T has the customers, and QWEST doesn't. What makes him think QWEST can steal AT&T's customers? There are switching costs, including switching out the local loop. AT&T is a known commodity and has established relationships. QWEST is a ??? Sure, they will win some business, but only by aggressively offering discounts. But they won't kill AT&T IMO.
Assuming QWEST is wildly successful at recruiting customers, at that point they will have to worry about congestion. It's the router (not the fiber) that is the bottleneck, and QWEST is putting a lot of faith that by that time, Cisco will have resolved the QoS issue. If not, then they'll have no choice but turn to ATM.
bucky89 |
