ANTS Goals
• Today’s networks lack flexibility …
Seek to allow new network services
to be introduced rapidly.
• Active networks are an appealing solution, but no
convincing demonstration that they can work …
Evaluate the hypothesis that they can provide useful
flexibility at a reasonable security/performance cost.
Nov 97
djw
1
ANTS Architecture
• Approach
– 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
2
ANTS Glossary
• Node
– 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
3
Capsules are Generalized Packets
Protocol+Program Id
Header
Node
Data
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
4
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
5
Code is Loaded at Routers
need to be efficient, adaptive, and load-limited
previous
node
load
request
loading
node
time
load
response
• application provides code at end systems, while
node loading is triggered by capsules
Nov 97
djw
6