ABone Architecture and Operation ABCd — ABone Control Daemon Server for remote EE management On-demand EE initiation and termination Automatic EE restart (permanent EEs) Java and C debugging support Node management support File upload/download Script execution (management “EE-lets”) Self-management capabilities Event logging and status reporting Reconfiguration and restart Supports the ABone security model Runs as an ordinary, unprivileged user Netiod — Network I/O Daemon Packet I/O service for EEs and AAs Implements Node OS channel abstraction Uniform I/O interface across node OSs Supplements OS kernel filtering capabilities Normally runs as a root-privileged service Can run in user space ABone Registry Central database maintained by ABOCC User contact data and public authentication keys Core node information Trusted code server data Access control (ACL/TCL) data Features User self-service for contact data, keys, and nodes Administrative functions for ABOCC Secure Web interface ABone support functions Automated ACL/TCL generation and distribution Node and contact lists to support monitoring tools Usability Features ABCd Client GUI Guided command construction Context-sensitive menus Intuitive explanations No syntax to learn Command history and recall Uses ABCd client Java API Modular library implementation Supports custom client development ABoneShell Client/server extensions to ABCd Simplifies common tasks EE management File transfer Problem diagnosis Client user interface Unix shell-like command tool Scripting capabilities Command history and recall Remote server extension Special-purpose EE-let Transparently invoked ABoneMonitor Web-based node and EE monitor Real-time ABone status reporting Graphical summary views Permanent EE topologies Whole ABone Table-based detailed views Node liveness ABCd status EE and AA status High-Level Design Core nodes Centrally administered community resource Required to be continually available Support multiple EE topologies in permanent configurations Edge nodes Private nodes controlled by individual developers Not registered as part of the testbed Dynamically join and leave permanent EE topologies Composed of Two Node Types Active Applications (AAs): Java and C (EE-dependent) Execution Environments (EEs): Java and C Node Operating System (Node OS): Unix/POSIX-based Based on the Active Networks Reference Architecture Active Applications (AAs) Fundamental unit of network programming AA code may migrate from node to node Execution Environments (EEs) Environment for AA execution Stable part of active node software Node Operating System (Node OS) Environment for EE execution Permanent part of active node software... Node OS EE AA... EE AA... Reference Architecture for Active Nodes Developed by the Active Networks Community ABone Security Model Trusted EEs, untrusted AAs All code executed within ordinary Unix user accounts EEs may be downloaded only from trusted servers EE code trusted not to be malevolent AA trust requirements EE-dependent Access controls ACL files control who may perform what operations TCL files control who may use which EE code servers File integrity Guarded by Unix file permission rules Security-critical files strictly separated from EE/AA files Node access ABOCC trusted to maintain ACL/TCL files Node administrators control root access ABone Node Architecture Authentication & Access Control Command Processing Client Communications EE Downloading and Execution Unix Operating System EE ABCd Netiod EE Code Server ACL/TCL Server Remote User Channel Control Packet Filtering Control messages InChannel OutChannel Network I/O AA AA Code Server