| In today's Internet, hosts communicate with each other via intermediate message processors called roisters, and the messages are called packets. In the early Internet, the roisters used to passively forward the packets. As the Internet continued to grow, there was a need for more functionality from the roisters. Some of the roisters then started implementing additional functionalities such as firewalls for security reasons. The trend to make the network more intelligent has continued, and roisters that are capable of much more complex actions have been proposed. Such networks that actively participate in the packet forwarding are called active networks.;The Internet is a packet network, and the overheads of routing the packets are on a per-packet basis rather than on per-byte basis. To reduce the overheads, we propose a new protocol called “gathercast”. Gathercast allows us to combine multiple small packets into a larger packet, thereby reducing the number of packets in the network. One important advantage of reducing the number of packets is reduced drops at intermediate roisters. Whenever a roister receives a burst of packets that it cannot transmit immediately, it buffers the incoming packet in a queue. The queue is limited by the number of packets and not by the number of bytes. Therefore, a reduction in packets leads to a reduction in drops at intermediate roisters.;We also propose the concept; of transformer tunnels. Transformer tunnels are like any other IP tunnel, but they allow users to modify the packets flowing through them. This modification (that we call a transformation function) could be packet compression, encryption, retransmission, and so on. We studied one particular transformation function called aggregation. The aggregation function combines two more small packets into a larger packet. Gathercast uses this aggregation function for reduction of packets in the network.;We show the effect of aggregation on cache proxies that use Internet Cache Protocol (ICP), on a combination of UDP and TCP flows, and on web servers. We also propose a protocol called “gathercast” to dynamically deploy these aggregators in the network.;We have implemented transformer tunnels, and gathercast on a Linux-based system. |
