1. The Active Node Transfer System By Chris McAnally & Manu Mittal
Ants
The Active Node Transfer System By
Chris McAnally
&
Manu Mittal

2. The Current Network Architecture
Currently routing behavior is fixed
But performance is heavily dependant on network services
New protocols and services are rapidly being developed but deployment is long and difficult
One Solution
Standardize the communications model rather than individual protocols.

3. Ants Overview
Treats the network as a restricted distributed computing environment.
Provides a scripting language model to express new protocols as operations at nodes.
Allows dynamic deployment

4. Goals
3 Goals
Simultaneously support a variety of protocols and services
Support the construction of new protocols through mutual agreement
Support dynamic deployment of new protocols

5. The model Protocols Capsule Code Groups
To replace the packet we use capsules which refer to the forwarding routine used to process them.
Code Groups
A collection of Capsules whose forwarding routines are transferred as a group by the code distribution system.
Protocols
A collection of related code groups that are treated as a single unit of protection.

6. Architecture
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7. Type Field
An Identifier that tells the associated protocol and forwarding routine.
Based on a secure hash of the forwarding routine.
MD5 hash function
Provides a fingerprint of code for security
Prevents protocol spoofing

8. Active Nodes
The biggest problem with a programmable network is ensuring the safety of forwarding routines.
Solution
Each node provides a set of primitives that are used to construct forwarding routines
Active nodes limit access to resources

9. Node Primitives 10 Primitives that fall into 3 categories
Environment Calls
Return local information, such as address, etc.
Storage calls
Objects stored in a “soft-state” i.e. cached
Application determines the caching interval
Control Operations
If no control operation is called, it’s discarded.

10. Execution Model Four main Characteristics Fixed Forwarding Routine
The forwarding routine is fixed at the sender
Designed to prevent a bandit from hijacking another application’s capsules
Selective Execution
Capsules belonging to protocols the active node chooses not to execute are handled as regular IP packets

11. Execution Model(continued)
Resource Limits
Cache time
Soft-state storage space
Network bandwidth
Protocol-based Protection
Only capsules belonging to the same protocol can share state

12. Code Distribution System
1). Capsules identify their type
2). When a capsule arrives at a node the cache is checked. If it’s not there the previous node is queried and execution is suspended.
3). When a node receives a load request it responds immediately.
4). When a node receives a load response it places it into the cache and activates the sleeping capsules.