Clemens Vasters, Technical Lead at Microsoft, delivered a demonstration of Windows Azure Service Bus with a comprehensive review of its programming model. In his presentation he elaborated on the points he was making last fall on this blog:
The primary obstacle to creating pervasive connectivity is that we have run out of IPv4 addresses. There is no mere threat of running out, we're already done. The IPv4 space is practically saturated and it's really only network address translation (NAT) that permits the Internet to grow any further. The shortage is already causing numerous ISPs to move customers behind NATs and not to provide them with public IP address leases any longer. Getting a static public IP address (let alone a range) is getting really difficult. IPv6 holds the promise of making each device (or even every general-purpose computer) uniquely addressable again, but pervasive IPv6 adoption that doesn't require the use of transitional (and constraining) tunneling protocols will still take many years.
The second major obstacle is security. Since the open network is a fairly dangerous place these days and corporate network environments are often und unfortunately not much better, the use of Firewalls has become ubiquitous and almost all incoming traffic is blocked by default on the majority of computers these days. That's great for keeping the bad guys out, but not so great for everything else – especially not for applications requiring bi-directional connectivity between peers.
Windows Azure Service Bus is an infrastructure that enables
an application or service can expose and access endpoints that would otherwise be hard or impossible to reach. For example, the endpoints may be located behind network address translation (NAT) boundaries or bound to frequently changing, dynamically assigned IP addresses.
The ASB offers "VPN-like" functionality for connecting business partners across the Internet with the ability to deal fairly transparently with the idiosyncrasies of Internet protocols. The ASB also works with SilverLight for which it establishes short-lived dynamically provisioned routers and queues which are removed as soon as a user's client has not pinged the ASB.
Clemens announced that he will resume blogging again as his work is now public.