Draft: draft-ietf-dnssd-srp

Commentary: Add a bunch of references , and some editorial tweaks .
Paragraph (version A):
The RFC6763 ("Populating the DNS with Information"), briefly
discusses ways that servers can publish their information in the DNS
namespace.  In the case of mDNS, it allows servers to publish their
information on the local link, using names in the ".local" namespace,
which makes their services directly discoverable by peers attached to
that same local link.
Paragraph (version B):
The DNS-SD specification (RFC6763, "Populating the DNS with
Information"), briefly discusses ways that servers can publish their
information in the DNS namespace.  In the case of mDNS, it allows
servers to publish their information on the local link, using names
in the ".local" namespace, which makes their services directly
discoverable by peers attached to that same local link.
Paragraph (version A):
First-Come First-Serve naming provides a limited degree of security:
a server that registers its service using DNS-SD Registration
protocol is given ownership of a name for an extended period of time
based on the key used to authenticate the DNS Update.  As long as the
registration service remembers the name and the key used to register
that name, no other server can add or update the information
associated with that.  FCFS naming is used to protect both the
Service Description and the Host Description.
Paragraph (version B):
First-Come First-Serve naming provides a limited degree of security:
a server that registers its service using DNS-SD Registration
protocol is given ownership of a name for an extended period of time
based on the key used to authenticate the DNS Update.  As long as the
registration service remembers the name and the key used to register
that name, no other server can add or update the information
associated with that.  If the server fails to renew its service
registration before the KEY lease (I-D.ietf-dnssd-update-lease), its
name is no longer protected.  FCFS naming is used to protect both the
Service Description and the Host Description.
Paragraph (version A):
compressing in RFC2782 is not stated, but is assumed to be because a
caching resolver that does not understand the format of the SRV
record might store it as binary data and thus return an invalid
pointer in response to a query.  This does not apply in the case of
SRP: an SRP registrar needs to understand SRV records in order to
validate the SRP Update.  Compression of the target potentially saves
substantial space in the SRP Update.
Paragraph (version B):
compressing in RFC2782 is not stated, but is assumed to be because a
caching resolver that does not understand the format of the SRV
record might store it as binary data and thus return an invalid
pointer in response to a query.  This does not apply in the case of
SRP: an SRP registrar needs to understand SRV records in order to
validate the SRP Update.  Compression of the target potentially saves
substantial space in the SRP Update.  SRP registrars MUST support
compression of SRV RR targets.
Paragraph (version A):
The registrar MAY add a Reverse Mapping that corresponds to the Host
Description.  This is not required because the Reverse Mapping serves
no protocol function, but it may be useful for debugging, e.g. in
annotating network packet traces or logs.  In order for the registrar
to do a reverse mapping update, it must be authoritative for the zone
that would need to be updated, or have credentials to do the update.
The SRP requestor MAY also do a reverse mapping update if it has
credentials to do so.
Paragraph (version B):
The registrar MAY add a Reverse Mapping (RFC1035, RFC3596) that
corresponds to the Host Description.  This is not required because
the Reverse Mapping serves no protocol function, but it may be useful
for debugging, e.g. in annotating network packet traces or logs.  In
order for the registrar to do a reverse mapping update, it must be
authoritative for the zone that would need to be updated, or have
credentials to do the update.  The SRP requestor MAY also do a
reverse mapping update if it has credentials to do so.