Hi, Thanks, Joe, for the thoughtful review. Extracting some light from yesterday's discussion and RFCs 6335 and 2782, much of the contention seems to be around whether there could be two assigned names for related services that both happen to be provided over a given assigned port number. I'd like to propose an adjustment of the request, in light of the RFC text, and ask your judgment on how that adjusted request would fit within the services rubric that's outlined. In RFC 6335, explicit room is carved out for "assigned service name[s] without [a] corresponding fixed port number" with explicit reference to RFC 2782. Such a service name assignment would be completely adequate for purposes of the "NFS domain root" concept. As I read RFC 6335, such assignments are RECOMMENDED, and that IANA strives to assign such names under a first-come first-served policy (with reference to RFC 5226). In this formulation, the existing "nfs" service could stand unaffected. The proposed service, "nfsdomainroot", would request name assignment without a port number. The NFS client would seek SRV records under names such as "_nfsdomainroot._tcp.example.com". The result processing would continue as before, with SRV records indicating the hosts providing NFS service for the root of "example.com"'s file system. The SRV record then includes the port number on which the target NFS hosts provide "nfsdomainroot" service, which is given as an application of the NFS protocol in the subject I-D (including a mount point). The I-D would also need to propose, in the IANA section, that IANA assign the service name SRV nfsdomainroot TCP to this protocol. UDP service name allocation is unnecessary. In the judgment of the TSVDIR, would this take the I-D in a more acceptable direction? Craig > -----Original Message----- > From: Joe Touch [mailto:touch@xxxxxxx] > Sent: Sunday, September 11, 2011 4:12 PM > To: draft-ietf-nfsv4-federated-dns-srv-namespace@xxxxxxxxxxxxxx; tsv- > ads@xxxxxxxxxxxxxx; ietf@xxxxxxxx; nfsv4@xxxxxxxx > Cc: tsv-dir@xxxxxxxx > Subject: [nfsv4] TSVDIR review ofdraft-ietf-nfsv4-federated-dns-srv- > namespace > > Hi, all, > > I've reviewed this document as part of the transport area directorate's > ongoing effort to review key IETF documents. These comments were > written primarily for the transport area directors, but are copied to > the document's authors for their information and to allow them to > address any issues raised. The authors should consider this review > together with any other last-call comments they receive. Please always > CC tsv-dir@xxxxxxxx if you reply to or forward this review. > > This document describes the use of DNS SRV records to coordinate NFS4 > use and a global file namespace across a groups of clients and servers. > > There are no transport protocol issues in this document. The key > transport issue is the definition of a new DNS SRV record and its > associated syntax. > > There are issues with the intended syntax of the proposed DNS SRV > record. The current syntax is defined in RFC 2782 as: > > _service._transport.NAME > > service is an IANA SRV name, the namespace of which is defined in > RFC 6335 > > transport is _TCP or _UDP > > NAME is a DNS FQDN > > Given other considerations below (on versioning), the record should be > one of the following > > _nfs._tcp.example.com TTL Class SRV Priority Weight Port Target > _nfs._udp.example.com TTL Class SRV Priority Weight Port Target > > All other information specific to the exchange, e.g., organization > (which may or may not be a suffix of the Target, FWIW), desired mount > point, and various NFS-specific capabilities (e.g., mount options) > ought to be expressed in an associated TXT record as defined fields, as > is the case with other services that use SRV records. These options can > have defaults if not otherwise present. > > Some other issues are discussed below. > > Overall, the above is the key concern, and needs to be addressed before > proceeding. Issues below are indicated as either critical or > suggestions for clarification. > > Joe > > ------------------------ > > Critical issues: > > - the IANA section is incomplete > This document needs to request IANA assign an SRV service name, e.g.: > > SRV nfs TCP > SRV nfs UDP > > It is not clear whether an additional assignment of "SRV nfs SCTP" is > required; recent discussions on other SCTP SRV uses suggest that UDP is > indexed in these cases instead. This might warrant further discussion. > > - the service name should not include the version number > As per RFC 6335, and to be consistent with the existing port > assignments for NFS Version 4. > > - the discussion of list of organizations as with root.afs should be > described in a little more detail > The current sentence is a bit cryptic; this could be a full paragraph, > perhaps with an example. > > - there is no appropriate place to indicate write vs read-only in the > DNS request > The DNS request should return all available options, and indicate write > vs. read-only in the associated TXT records. The client should then > determine which is desired. > > ---------------------- > > Other issues (intended as suggestions): > > - version 4 > Throughout this document, "version 4" is used wherever NFS is used. > Since V4 (more specifically, 4.1) is the current common version, it > does not seem necessary to include this marking in most places except > where differences in the NFS versions are being highlighted. > > - colloquial advice > Terms like "appropriate" and "useful" should be removed throughout. > They represent judgements whose evaluation criteria is not discussed. > > - overall writing style > The document is written in the tense and style of a proposal. It should > be revised to read as the intended specification it will become. "We > propose" and "We use", and similar styles should be replaced with "this > document specifies" and "this record uses". > > - clarify overloaded terms > Terms like "root" and "name space" are widely used in different ways in > the DNS and file systems. Because this document combines the two, each > use should be clarified by a preceding term, e.g., DNS name space or > file system name space, DNS root or file system root. > > - the use of RFC 2119 terms should be reviewed > In particular, SHOULD should be used only where a specific exception is > currently known or suspected, and that exception described. This > provides the motivation for the selection of SHOULD vs. MAY or MUST. > > - the discussion of client vs server implementation (sec 4.3, as well > as partly in sec 4.2) should consider client-specific DNS responses > The DNS could provide responses that vary based on the IP of the client. > This could be a desirable feature. Further, the client knows whether it > wants write or read-write copies. AFAICT, the client is not only the > better place to implement this capability, it is the only viable place. > > - I found the hidden directory name discussion odd > It does not make sense to overload read-only with directory visibility; > these are orthogonal issues. The desired mount point should be > indicated in the TXT record; if a default convention is desired, it > should be indicated in the description of that field. > > - the AMD reference is only a web page > Not sure which particular reference is best, but a permanent reference > would be useful, e.g.: Matthew Crosby. 1997. AMD-AutoMount Daemon. > Linux J. 1997, 35es, Article 4 (March 1997). > > ----- > > > _______________________________________________ > nfsv4 mailing list > nfsv4@xxxxxxxx > https://www.ietf.org/mailman/listinfo/nfsv4 _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf