Browse Prior Art Database

DNS Support for Load Balancing (RFC1794)

IP.com Disclosure Number: IPCOM000004048D
Original Publication Date: 1995-Apr-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 8 page(s) / 14K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

T. Brisco: AUTHOR

Abstract

This RFC is meant to first chronicle a foray into the IETF DNS Working Group, discuss other possible alternatives to provide/simulate load balancing support for DNS, and to provide an ultimate, flexible solution for providing DNS support for balancing loads of many types.

This text was extracted from a ASCII document.
This is the abbreviated version, containing approximately 19% of the total text.

Network Working Group T. Brisco

Request for Comments: 1794 Rutgers University

Category: Informational April 1995

DNS Support for Load Balancing

Status of this Memo

This memo provides information for the Internet community. This memo

does not specify an Internet standard of any kind. Distribution of

this memo is unlimited.

1. Introduction

This RFC is meant to first chronicle a foray into the IETF DNS

Working Group, discuss other possible alternatives to

provide/simulate load balancing support for DNS, and to provide an

ultimate, flexible solution for providing DNS support for balancing

loads of many types.

2. History

The history of this probably dates back well before my own time - so

undoubtedly some holes are here. Hopefully they can be filled in by

other authors.

Initially; "load balancing" was intended to permit the Domain Name

System (DNS) [1] agents to support the concept of "clusters" (derived

from the VMS usage) of machines - where all machines were

functionally similar or the same, and it didn't particularly matter

which machine was picked - as long as the load of the processing was

reasonably well distributed across a series of actual different

hosts. Around 1986 a number of different schemes started surfacing

as hacks to the Berkeley Internet Name Domain server (BIND)

distribution. Probably the most widely distributed of these were the

"Shuffle Address" (SA) modifications by Bryan Beecher, or possibly

Marshall Rose's "Round Robin" code.

The SA records, however, did a round-robin ordering of the Address

resource records, and didn't do much with regard to the particular

loads on the target machines. Matt Madison (of TGV) implemented some

changes that used VMS facilities to review the system loads, and

return A RRs in the order of least-loaded to most loaded.

The problem was with SAs was that load was not actually a factor, and

TGV's relied on VMS specific facilities to order the records. The SA

RRs required changes to the DNS specification (in file syntax and in

record processing). These were both viewed as drawbacks and not as

general solutions.

Most of the Internet waited in anticipation of an IETF approved

method for simulating "clusters".

Through a few IETF DNS Working Group sessions (Chaired by Rob Austein

of Epilogue), it was collectively agreed upon that a number of

criteria must be met:

A) Backwards compatibility with the existing DNS RFC.

B) Information changes frequentl...