NITs I found while reading the SIP spec
Yaron Goland <yarong@microsoft.com> Tue, 28 April 1998 08:16 UTC
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From: Yaron Goland <yarong@microsoft.com>
To: "'confctrl@isi.edu'" <confctrl@ISI.EDU>
Subject: NITs I found while reading the SIP spec
Date: Tue, 28 Apr 1998 01:15:28 -0700
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5 NITs 5.1 1.3 Definitions In general I find it more useful to be given definitions in order of dependence rather than in alphabetic order but that is just personal preference. Call - Has an open "(" with no close ")" Final Response - The sentence is syntactically confusing. I would suggest something along the lines of: Final Response: A response that terminates a SIP transaction, as opposed to a provisional response that leaves the transaction outstanding. Invitation - The spacing for Invitation contains an "a" that should be an "an", it currently says "an INVITE request followed by a ACK request." It should read "an INVITED request followed by an ACK request." Location Service - "beyond the scope of THIS document" not "the". 5.2 1.4.2. Locating a SIP Server After explaining the various steps to resolve an address the spec states "If a server is found using one of the methods below, the other methods are not tried. " Since are specified previous to the sentence it would be more appropriate to state "If a server is found using one of the previous methods..." 5.3 1.4.5. Location a User First Paragraph, last sentence, reads: "The location services yield a list of a zero or more possible locations, possibly even sorted in order of likelihood of success." I would rephrase this as "The location services yield a list of zero or more locations, possibly sorted in order of likelihood of success." Third Paragraph, second sentence, remove the word "simply", it is an unnecessary modifier. In general I think it is unnecessary to discuss location servers. It is always best to leave unspecified things, unspecified. You need only describe behavior within the strict purview of SIP. So how a proxy or redirect server actually gets an address is its own business. I think matters are just confused by going into long discussions about location servers and alternate protocols. It is much less confusing to just say "A proxy/redirect server will use its own mechanisms to determine one or more addresses for the specified callee." Less is more, especially in an 106 page draft. Fourth Paragraph, third sentence, "each host most remove its Via," I suspect you mean "each host MUST remove its Via". Second to Last Paragraph, last sentence, you specify that user agents SHOULD NOT notify the user when duplicate requests are received. I personally dislike UI requirements in protocol specs. It is completely appropriate to state that receiving two requests, because of forking, is NOT an error and as such there is no need to notify the user but please do not put SHOULD level requirements on UI. 5.4 2 SIP Uniform Resource Locators RFC 1630 is out of date. The more correct guide is http://www.ietf.org/internet-drafts/draft-fielding-uri-syntax-02.txt. Why does the SIP URL begin with "SIP://" when no hierarchical namespace (authority) is being defined? The correct format would be "SIP:". Why do short SIP URLs have a production for port but full SIP URLs do not? There is a draft out on how to create telephone URLs (http://www.ietf.org/internet-drafts/draft-antti-telephony-url-04.txt). I would suggest carefully reviewing it and thinking of revising your own phone production based on the extensive information provided in the draft. Your hostnumber production does not support IPv6 No production is given for password I honestly don't grok the headers production. What is the huge quote enclosed space for? I searched [19], I can't find any reference to urlc. While it is true that the short form SIP URL can be used unambiguously it is a general principal of protocol design to never provide two ways of doing the exact same thing. This just leaves more room for screw ups. I would strongly urge the group to reconsider the wisdom of saving 4 bytes (assuming the groups uses SIP:) at the cost of increasing complexity. 5.5 6.18 From The second sentence of the first paragraph states that "The field MUST be a SIP URL..." but then the first sentence of the second paragraph states "The >From field is a URI..." which the BNF backs up. The two sentences contradict each other. 5.6 6.38.3 Syntax What rx parameter? I suspect you mean "received" parameter. Either that or "rx" is the short form of received, in which case it needs to be added to the BNF. 5.7 6.39 Warning The BNF for the warn-code is 2DIGIT but you use a four digit with a "." warning format because of your desire to use 606 warnings. I would suggest that this is an inappropriate use of the warning header. Instead your should introduce new 6xx codes to cover what you now call warnings. Regardless of the outcome, either the examples must change or the BNF production for warn-code in 6.39 must be changed. 5.8 10 SIP Transport Um.. what is the story with section 10 & 11? It looks like some kind of editing error. 5.9 14.1.2 The Authorization Request Header Shouldn't signed-by just be a URI? Why does it have to be a SIP-URL?
- NITs I found while reading the SIP spec Yaron Goland
- Re: NITs I found while reading the SIP spec Henning Schulzrinne
- RE: NITs I found while reading the SIP spec Yaron Goland
- Re: NITs I found while reading the SIP spec Henning Schulzrinne