Embed Size (px)
DESCRIPTION
Service Location Protocol: Automatic Discovery of IP Network Services. Erik Guttman, Sun Microsystems IEEE INTERNET COMPUTING, July-August, 1999 2005.10.17 Jongsoo Lee ( [email protected] ). Content. Introduction How can I use …? Background Service Location Protocol Comparison - PowerPoint PPT Presentation
Citation preview
Erik Guttman, Sun MicrosystemsIEEE INTERNET COMPUTING, July-August, 1999
2005.10.17
Jongsoo Lee ([email protected])
Service Location Protocol:Automatic Discovery of IP Network Services
2/14
Content
Introduction How can I use …? Background
Service Location Protocol
Comparison
Conclusion
3/14
How can I use …?
A certain laboratory in SNU
Printer
NTPserver
How can I print?
Printer IP is ……
How can I sync time?
NTP serverIs ……
How can I use
news?
No news server.
They invite a guest for some project.
It’s uncomfortable!!!
4/14
Background
Problems with Earlier Protocols Discover services only by type Notorious lack of scalability
Service Location Protocol (SVRLOG) WG 1997 : Version 1 (RFC 2165) 1999 : Version 2 (RFC 2608) 2002 : Vendor Extensions (RFC 3224)
SUN, Novell, IBM, Apple, HP, …
5/14
Content
Introduction
Service Location Protocol Architecture Operation For Various-size Network Additional Features
Comparison
Conclusion
6/14
Architecture
Agents User Agents (UA) : service discovery Service Agents (SA) : service advertisement Directory Agents (DA) : service info aggregation
SA
UA
UA
DA
SA
UA
UA
UA
SA
SA
SrvRqst (m)SrvRply (u)UA DAAdvert (m)SrvRqst (m)
DAAdvert (u)
SAAdvert (u)
SrvRqst (u)
SrvReg (u)SrvAck (u)SrvRply (u)
7/14
Operation
Service Advertisements Service URL contains service’s location Follow the service templates (registered with IANA)
־ Attributes, default values and interpretation
DA Discovery Multicast Convergence Algorithm Active / Passive discovery DHCP
Service Templates, and search filters = LDAPv3
8/14
Operation - messages
Mandatory Service Request : 1 Service Reply : 2 Service Registration : 3 Service Acknowledge : 5 DA Advertisement : 8 SA Advertisement :11
Optional Service Deregistration : 4 Attribute Request : 6 Attribute Reply : 7 Service Type Request : 9 Service Type Reply : 10
SrvRqst : service-type, scope-list, predicate SrvRply : URL-list SrvReg : service-type, scope-list, attr-list Advertisements : URL, scope-list, attr-list
9/14
For Various-size Network
Larger Network More DA Scope
־ A string used to group resources by location, network, or administrative category
־ DHCP → static configuration → “DEFAULT”
Small Network SLP can work without DA, DNS and DHCP
UA
SA
SA
SAguest
administrator
Scope = “guest”
10/14
Additional Features
Security Authentication of the source of information. SrvReg of SA include a digital signature using public key DA is also possible
Browsing Service Type Request Attribute Request
IPv6 Designed to provide service in IPv6 network But not yet been standardized
11/14
Content
Introduction
Service Location Protocol
Comparison
Conclusion
12/14
Comparison DHCP Service Options
Can’t determine a current available server
DNS Resource Records Can’t determine a current available server Only by type, and not by service characteristics
Simple Multicast Discovery Scalability
Jini Similar with SLP, but only for Java application
13/14
Content
Introduction
Service Location Protocol
Comparison
Conclusion
14/14
Conclusion
IETF standard for service discovery and automatic configuration of clients.
SLP provide fully decentralized operation
From a small network to an enterprise network
Convenience & Easy administration
![[MS-DVRD-Diff]: Device Registration Discovery Protocol](https://img.pdfslide.us/doc/110x75/61f3e04980b95f59ea64d265/ms-dvrd-diff-device-registration-discovery-protocol.jpg)
![[MS-PSDP]: Proximity Service Discovery Protocol](https://img.pdfslide.us/doc/110x75/6238aaa8e4670f2fd5332d72/ms-psdp-proximity-service-discovery-protocol.jpg)
![[MS-SNID]: Server Network Information Discovery Protocol](https://img.pdfslide.us/doc/110x75/6271cde4050c0356e705a635/ms-snid-server-network-information-discovery-protocol.jpg)
