service
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This document describes remote service discovery in the Service
Location Protocol (SLP) [RFC2608 ...
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This document describes remote service discovery in the Service
Location Protocol (SLP) [RFC2608] via DNS SRV ...
... DNS SRV [RFC2782]. We consider
remote service discovery as discovering desired services in given
remote DNS ...
... RFC2782]. We consider
remote service discovery as discovering desired services in given
remote DNS domains ...
... remote DNS domains, and local service discovery as discovering
desired services within the local administrative domain ...
... domains, and local service discovery as discovering
desired services within the local administrative domain.
...
... SLP provides a scalable framework for local service discovery and
selection. In SLP, User Agents ...
... SLP, User Agents (UAs) discover desired services in
the local administrative domain by querying all Service Agents ...
... services in
the local administrative domain by querying all Service Agents (SAs)
via multicast ...
...
DNS SRV provides good support for remote service discovery. However,
if multiple servers are discovered via DNS SRV for a service ...
... service discovery. However,
if multiple servers are discovered via DNS SRV for a service, only
priority and weight can be used to make a selection. If additional
...
... priority and weight can be used to make a selection. If additional
service properties (such as cost, speed and service quality) need to
be considered in the selection process, DNS SRV ...
... priority and weight can be used to make a selection. If additional
service properties (such as cost, speed and service quality) need to
be considered in the selection process, DNS SRV becomes insufficient.
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... SLP and DNS SRV together can provide better
support for remote service discovery. First, a UA uses DNS SRV to
...
... SLP to query
one of those DAs to discover desired services. In this way, we can
avoid the limitations in using SLP and DNS SRV ...
... SLP, DNS SRV has
limited support for service selection.
In this document, we first define the DNS SRV ...
... SLP and DNS SRV
together for remote service discovery. Finally, we give the steps
for discovering services in remote DNS ...
... together for remote service discovery. Finally, we give the steps
for discovering services in remote DNS domains.
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... where "slpda" is the symbolic name for SLP DA services, the Proto
field is either "tcp" or "udp", and the Target field is the domain
name ...
... RRs as described in this
document. The second approach is useful for UAs to acquire service
information for remote DNS domains. For example, a mobile node ...
... network (without the use of mobile IP) may want to obtain
information about services in its home network.
...
... domain where SLP DAs are registered. For remote service discovery,
it is assumed that the DNS domain ...
... SLP DAs for Remote Service Discovery ...
... SLP Scopes for Remote Service Discovery ...
... administrative
domain, they are likely incomprehensible to users outside of the
administrative domain. Thus, any remotely accessible service MUST be
registered in the "default" scope, but it MAY be registered in other
scopes at the same time. Similarly, all DAs advertised via DNS SRV ...
... DNS SRV
MUST serve the "default" scope, but they MAY serve other scopes at
the same time. As a result, users wishing to discover services at a
remote DNS domain ...
... Steps for Remote Service Discovery ...
... in D.
Note that the services discovered in the above steps may not
necessarily be remotely accessible.
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...
To support remote service discovery, a domain exposes its service
information to the Internet ...
... To support remote service discovery, a domain exposes its service
information to the Internet. Standard SLP authentication ...
... SLP authentication SHOULD be
used to protect valuable service information. First, there is a risk
that any SA could advertise any service ...
... service information. First, there is a risk
that any SA could advertise any service on a DA accessible from the
Internet ...
... deregistrations that cannot be authenticated. Secondly, to avoid
disclosing unintended service information to remote users, a DA
accessible from the Internet ...
... accessible from the Internet SHOULD at least authenticate service
queries that are not in the "default" scope. In addition, the
...
...
This specification describes remote service discovery in SLP via DNS
SRV. It facilitates discovering services ...
... service discovery in SLP via DNS
SRV. It facilitates discovering services at a remote DNS domain if
...
... the domain name is known via a priori knowledge. However, it does
not intend to solve the problem of Internet-wide service discovery.
Users should be aware of two constraints ...
... SLP scopes are not intended to be used outside the local
administrative domain, all remote service discovery in SLP SHOULD be
carried only in the "default" scope.
...
... carried only in the "default" scope.
Note that the services discovered via DNS SRV and remote SLP DAs may
...
... RRs for SLP DA services, the symbolic name for the
Service field is "slpda", supported protocols are "tcp" and "udp".
...
... DA services, the symbolic name for the
Service field is "slpda", supported protocols are "tcp" and "udp".
The following values have been registered with IANA:
...
... Guttman, E., Perkins, C., Veizades, J. and M. Day, "Service Location Protocol, Version 2 ", RFC 2608, June 1999. ...
... Gulbrandsen, A., Vixie, P. and L. Esibov, "A DNS RR for specifying the location of services (DNS SRV)", RFC 2782prop, February 2000. ...