Active Networks – The Network Future By Samatha Gangapuram Prashant Shanti Kumar Harish Kumar Maringanti

Assigned Unenviable task  What  Why  How  Where

Active Networks – What ? No general agreement beyond buzz phrases. “Active networks explore the idea of allowing routing elements to be extensively programmed by the packets passing through them.”

Legacy Vs Active Legacy Networks  Passive packet.  Rely on agreement about protocols.  Functionality built into each router.  Change is a long and wrenching process. Active Networks  Active Packet.  General agreement on model of computation.  Functionality in each packet.  Improved resilience to change.

AN - Services

Active Networks – Why ?  Rapid deployment and development.  Creating and Tailoring network services.  Better performance.  Open to deploy and administer.

Active Networks – How ? AN Paradigms  Programmable Switch Model  Capsule Model  Ad – hoc Model

Active Networks – How ? Programmable Switch :  Code is first transferred to the nodes, out – of – band.  Packets are treated as data or input to the code.

Active Networks – How ? Capsule Model :  Each packet is a program.  Each intermediate node executes the packet.

Active Networks – How ? Ad – hoc Model :  Packet contains flags.  Node contains in-built routines.  Based on flag, routines are executed.

A N - Terminologies  User Application (UA)  Active Application (AA)  Execution Environment (EE)  Node Operating System (NodeOS)

 The NodeOS is the base layer of any AN architecture.  It manages the resources of the active node and co-ordinates the resource demands.  NodeOS is also responsible for the enforcement of security policies. Examples SANE OS, JANOS, SCOUT, ExoKernel NodeOS

E E Nerve Center of the Active Node  Responsible for all aspects of user-network interface.  Nature of programming model and abstractions supported.  Addressing and Naming facilities. Examples SmartPackets, ANTS, CANE

A A  AA is a program and associated state capable of executing one or more active activities in a node, to perform some particular service.  AA is necessarily “portable” and dynamically installable or removable. Examples Active Reliable Multicasts, Protocol Boosters, Active Congestion Control.

A N - Architecture App 1App 2App 3App 1App 4App 3 Execution Environment A Execution Environment B Execution Environment A Execution Environment B Node OS Transmission Facilities

Packet Transition EE 3 EE 1 EE 2 ANEPIP ANEPIPUDP IP TCP IP UDPANEP I PUDP I P TCP I P ANEP

Implementation Challenges  The network should be usable  The network should have high flexibility  The implementation should be secure  The network should have high performance

Killer Arguments  Efficiency  Resource Allocation  Security

Efficiency Hiccups:  Bandwidth demand is growing faster than CPU speed – bad idea to execute arbitrary programs on packets.  Most programming languages are interpreted – JAVA byte code, plain interpreter. Cure:  Don’t propose AN for the core of the Internet.  Use just-in-time compilation, native code.  Hybrid architectures (high speed AN!)

Resource Allocation Hiccups:  Fairness in queuing is a problem.  Cannot guarantee QoS.  Cannot control Looping packets. Cure:  Provide distributed control (Scaling).  resource reservation in advance, resource preemption.  Limit capabilities of the active packet.

Security  Security cannot be limited to peripheral nodes.  Possible threats: Overload based Denial of Service Unauthorized access to the exposed control plane.  Secure Node doesn’t mean Secure Network.

Security at NodeOS  Security Enforcement through Authorizations.  Authorization policies are expressed in terms of Access Control Lists, which is a logical 3 - tuple of the form :  NodeOS has a security policy database and a policy enforcement engine.

Security at EE  Each EE has it's own protection policy, possibly a security database and an enforcement engine.  The programming model that an EE supports must also be restricted to ensure network security.  No broad consensus on the division of responsibility for policy enforcement between the NodeOS and the EE.

Security in SwitchWare  Uses ALIEN active loader.  Code Modules loaded on the fly.  Restricts access using namespaces.  Uses a language specification called CAML.

AN – APPLICATIONS  Network Management  Multicasting  Caching  Active Congestion Control  Security

Network Management  No polling required  "Patrol" and "first-aid" packets can track a problem and rectify it respectively.  Code moved to node rather than data to management center Example:Delegated Management. Decentralization helps in scalability, reducing delays from responses and effective bandwidth utilization.

Multicasting Active internal nodes elegantly solve many current problems such as:  NACK implosion.  Concentrated load of retransmissions.  Duplication of packets. Example: ARM Suppression of NACK & effective retransmission

Active Congestion Control  Selective dropping of units, packets or cells can be held very efficiently.  Multi-stream interaction. Example: APCI Backward compatibility with non-active nodes & on the fly routing employed.

Caching  Tradeoff between network based storage & bandwidth.  Location & time of storage crucial. Example: Self-organizing wide-Area Network caches: small number of caches within routers form large virtual cache.

Security  Node – Packet conflict.  Node security by authentication of active packets & PCC(Proof Correct Code).  Packet security by Fault-tolerance & Encryption. Example:SANE

AN - Services  Video on Demand  VPN  Multimedia Conferencing  VoIP / IP Telephony  Active Firewalling

AN - Services Web Browser Web Cache Web Server Proxylet Server Dynamic Proxy Server WebCache Proxylet Request Response Dynamic Proxy Server Audio Transcoder Remote Method Invocation Call Request Audio Response Proxylet Request Proxylet Response Audio File Request Audio File Response RTP Streamed Audio New Content-type or Redirection Header

“Retrofitting" AN to IP The Active IP Option:  Option in the IP header alerts the router to look at the packet payload more closely. Active Network Encapsulation Protocol (ANEP):  Adds a header that directs the router.

AN & Legacy

SmartPackets – A Case Study Uses Capsule model: Code with IP packet  Programs must be completely self-contained.  Operating environment provides security. Languages: Sprocket – A high level language Spanner – An assembly level language

SmartPackets – A Case Study Uses ANEP to fit with Legacy Networks NodeOs – JanOs EE – CANES/ASP AA - Network Management

SmartPackets – A Case Study Network Management Defines 4 types of packets:  Program  Data  Error  Message

SmartPackets – A Case Study Security For Nodes:  Authentication of packet  Cryptographic hash of non-mutable fields For packets:  Redirection  Encryption

SmartPackets – A Case Study Limitations  Packet size  Applications adaptability Scope Extending for other applications

Current Work  Active Nets at DARPA Active Nets  ActiveNets at MIT ActiveNets  ANTS at Washington ANTS  SwitchWare at UPenn SwitchWare  JANOS & OSkit at Utah JANOS & OSkit  Liquid Software at Arizona Liquid Software  Panda at UCLA Panda  NetScript at Columbia NetScript  CANES at Georgia Tech CANES  Smart Packets at BBN Smart Packets

Conclusion Is Active Network really the future ?

References Darpa Switchware CANES