RFC 998 (rfc998) - Page 1 of 21
NETBLT: A bulk data transfer protocol
Alternative Format: Original Text Document
Network Working Group David D. Clark
Request for Comments: 998 Mark L. Lambert
Obsoletes: RFC 969 Lixia Zhang
MIT
March 1987
NETBLT: A Bulk Data Transfer Protocol
1. Status
This document is a description of, and a specification for, the
NETBLT protocol. It is a revision of the specification published in
NIC RFC-969. The protocol has been revised after extensive research
into NETBLT's performance over long-delay, high-bandwidth satellite
channels. Most of the changes in the protocol specification have to
do with the computation and use of data timers in a multiple
buffering data transfer model.
This document is published for discussion and comment, and does not
constitute a standard. The proposal may change and certain parts of
the protocol have not yet been specified; implementation of this
document is therefore not advised.
2. Introduction
NETBLT (NETwork BLock Transfer) is a transport level protocol
intended for the rapid transfer of a large quantity of data between
computers. It provides a transfer that is reliable and flow
controlled, and is designed to provide maximum throughput over a wide
variety of networks. Although NETBLT currently runs on top of the
Internet Protocol (IP), it should be able to operate on top of any
datagram protocol similar in function to IP.
NETBLT's motivation is to achieve higher throughput than other
protocols might offer. The protocol achieves this goal by trying to
minimize the effect of several network-related problems: network
congestion, delays over satellite links, and packet loss.
Its transmission rate-control algorithms deal well with network
congestion; its multiple-buffering capability allows high throughput
over long-delay satellite channels, and its various
timeout/retransmit algorithms minimize the effect of packet loss
during a transfer. Most importantly, NETBLT's features give it good
performance over long-delay channels without impairing performance
over high-speed LANs.
Clark, Lambert, & Zhang