The NDN Testbed Topology
Testbed Overview
The concepts developed in the NDN project are implemented and explored using a working testbed that connects the many of the project sites. Essentially, the testbed links are UDP tunnels. Nodes on the testbed send Interest Packets and recieve Data Packets in response. The software on each site implements all the primary concepts of NDN, including Data Caches and Pending Interest Tables .
Hub and Nodes
As shown in the topology figure above, each site operates an NDN hub. The hubs maintain long standing GRE tunnels to each other to exchange routing information via OSPF. Users at each site connect laptops and desktops to the local hub. The laptops and desktops learn ccnx names from the hub using the ccnx-dhcp software suite.
Faculty and students have the testbed code installed on their laptops and dynamically join and leave the tested by connecting to the hub at their institution. A laptop joins the testbed by establishing a UDP tunnel and thus the laptops may be located on campus, at home networks, or any location. Essentially, the machines can be anywhere in the Internet (provided firewalls don't block the tunnels).
Testbed Applications
The NDN applications team continue to build and deploy new applications that run natively over NDN. Example applications include ccnchat, a simple text chat tool that allows users to communicate and is often used for testing connections and managing testbed operations. An audio conferencing tool is nearly complete (as of January 2011) and future NDN confernce calls are to be held over the testbed. Other applications ranging from operational tools such as a version of ping and a variety of task specific user applications are also under development.
Joining the Tesbed
The NDN Testbed Code is available as open source from GitHub. Anyone can download the code and easily install their own hub and/or enable NDN on their desktop/laptop. We suggest anyone deploying the code review our instructions in the New User Guide.
However, we are currently not accepting additional connections to our testbed. We have substantial on-going work on routing, forwarding, and network management that currently requires more control over the topology and users. We envision opening the testbed to all sites once the basic challenges of network routing, forwarding, and management are fully developed and relatively stable.