1. ANTS Goals Today’s networks lack flexibility …
Active networks are an appealing solution, but no convincing demonstration that they can work …
Seek to allow new network services to be introduced rapidly.
Evaluate the hypothesis that they can provide useful flexibility at a reasonable security/performance cost.
Nov 97
djw

2. ANTS Architecture Approach Model Goal
uncoordinated introduction, automatic deployment
application-specific protocols used “on-the-fly”
Model
programmable routers generalize IP forwarding
mobile code used to implement new services
Goal
show feasibility/usefulness, explore tradeoffs
Nov 97
djw

3. ANTS Glossary Node Capsule Protocol Application
programmable router that implements services
Capsule
generalized packet (header + data + program)
different capsule types have different programs
Protocol
communication rules that provide a service
codified as set of related capsule types
Application
network client that uses services via protocols
Nov 97
djw

4. Capsules are Generalized Packets
Protocol+Program Id
Header
Data
Node
Node
Capsule
carry the program and protocol by reference using a fingerprint to prevent code spoofing
header includes at least fields for default forwarding, resource limits and source identification
Nov 97
djw

5. Node Operating System hosts user-defined protocols
capsule API: soft-storage, routing, …
admits new protocols at its discretion
protects network/protocol integrity
executes untrusted code, limits resource use
provides each protocol with its network “view”
distributes code among nodes
Nov 97
djw

6. Code is Loaded at Routers
need to be efficient, adaptive, and load-limited
previous
node
loading
node
load
request
time
load
response
application provides code at end systems, while node loading is triggered by capsules
Nov 97
djw