1. Programming with ANTS
ANTS facilitates protocols construction and deployment
Demonstrate some examples using
Mobility services
Multicasting

2. Mobility Services Involves 2 types of capsules
One is sent by mobile hosts to register forwarding information while its roaming
Other is used by other hosts (source) to send messages to the mobile host while its roaming
Home Agent is used to intercept messages at the base location of the mobile host
Foreign Agent is used as a “care of” address to reach the mobile host while its away from its base

4. Mobile Hosts role :
Periodically send “Register” capsules to their Home Agent Via the Foreign Agent
This capsule updates forwarding address cached at the home and the foreign Agent
Home Agent’s role:
When other sources send information for the Mobile Host, capsule discovers a forwarding pointer as it traverses the home agent and follows it to the foreign agent
Foreign Agent’s role:
Maintains a pointer to the Mobile Host
When it receives a capsule intended for the Mobile Host it simply forwards it

5. Multicast Consists of 2 types of capsules:
Subscribe capsules: Send by applications that wish to receive messages sent by a particular sender, send these towards the sender
Multicast Data capsule: To multicast to the group, the sender node sends these capsules which simple route themselves along the distribution tree

7. Subscribe program:
Looks up the forwarding record for the group in the node cache or creates a new one if none is found
To distinguish between different multicast sessions in the cache;
The record is stored in a key which is a combination of the group and the sender’s address
Once a forwarding record is located, a “reverse” pointer in the direction of the subscriber is merged into the forwarding record
(Leaf subscribers have empty forwarding lists)

8. Multicast Data program:
Makes use of the forwarding records found at the nodes, sending copies along every indicated “reverse” path.
At end systems where there is an empty forwarding record, capsule is delivered to the application.
special multicast routers are not needed; this scheme is localized to the nodes using this protocol

9. Prototype Implementation
Done in JAVA
Classes Involved:
Node class: Represents the runtime of a single network node
Channel class: Provides interface to the link layer connecting nodes via point-to-point or shared medium channels
Capsule class: virtual class to create capsules specialized to protocols
Application class: Container for end system processing that provides a small API for registering protocols, injecting capsules into the network and receiving capsules from the network.

10. Source: http://www. cs. washington

12. Related work done in this field are on websites below
David Weatherall's thesis :
(pg 135)

13. Conclusion
Allows new protocols to be automatically, dynamically, and rapidly deployed to exact those nodes where needed
Required no advanced consensus about the kinds or definitions of the protocols.
Can provide means for automatically upgrading network protocols; can remove barriers to innovation, stimulate experimentation, and hasten the arrival of new functionality.