Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!mcsun!ukc!stc!datlog!gjack From: gjack@datlog.co.uk ( Graham Jack) Newsgroups: comp.protocols.tcp-ip Subject: Re: timimg-out a socket read Message-ID: <2904@dlvax2.datlog.co.uk> Date: 27 Jun 90 09:58:59 GMT References: Organization: Data Logic Ltd, Queens House, Greenhill Way, Harrow, London. Lines: 36 ihsan@ficc.ferranti.com (jaleel ihsan) writes: >I do not know of any other means of timing-out the read except to use the >keep socket "warm" option, ... If the supplier's offering doesn't give the facilities you want, you can provide them in your own 'session-layer', it ain't pretty but its pragmatic. The rationale used against an effective 'keepalive' at the transport layyyer seems to take a rather narrow view of the sort of applications and environments in which IPS is used these days. > ... but the vendor says (and quotes form the few >last pages of internetworking by Comer) that the standard does not require >him to implement it and even if he implements it the standard does not >require to make the timers in the option to be user selectable. What does >the standard has to say about this ? All credit to Comer for introducing me and many others to the Internet protocols but your supplier should be referring to the Host Requirements RFCs and in particular to Section 4.2.3.6 of RFC-1122. This says keepalives MAY be implemented (ie are OPTIONAL), if provided the interval MUST be configurable. Practically, if the products are based on the 4.3BSD networking code as many (most?) UNIX implementations are, then keepalive should be provided and should work, it is unlikely, however, to be configurable. That's life ... >Did I choose the wrong vendor, or did I made a mistake in choosing tcp-ip >for real-time application ? (8=:|) I'm not sure I can comment on this. -- Regards, Graham Jack, Data Logic.