DISCOVER: Supporting Multicast DNS Queries
Internet Draft Bill Manning
Expires: 29 january 2013 23 august 2012
Intendend Status: Historical
DISCOVER: Supporting Multicast DNS Queries
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This document describes the DISCOVER opcode, an experimental
extension to the Domain Name System (DNS) to use multicast queries
for resource discovery. This opcode was tested in experiments run
during 1995 and 1996 for the TBDS project. TBDS was the first known
use of multicast transport for DNS. A client multicasts a DNS
query using the DISCOVER opcode and processes the multiple responses
that may result.
The TBDS project developed extensions to existing network services to enable
application client and server software to become more resilient to changes in
topology by dynamically sensing changes and switching between client/server
and peer-peer methods for both end-system-to-server and server-to-server
The first existing network service to be investigated was the Domain Name
Systems (DNS) which is used to map symbolic Internet names to numeric Internet
addresses. Based upon a hierarchical tree structure, the DNS relies upon
uninterrupted connectivity of nodes to a special set of static, manually
configured root servers. To improve the robustness and availability of the DNS
service, TBDS developed and defined enhancements that enable nodes to map names
to numbers without the need for uninterrupted connectivity to the Internet
root servers. These techniques were automated, allowing transition between
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