RE: [Syslog] delineated datagrams

Hi Tom,

You're right; I didn't go far enough. I was looking for a framing
defined by the netconf protocol, not the separator of messages within
a transport. Unfortunately, Netconf uses a number of
transport-dependent schemes within the multiple transports it
supports, including both octet-counting approaches and terminating
character approaches. Sigh.

The "]]>]]>" sequence only works in the SSH transport mapping, not the
BEEP or SOAP mappings. So much for trying to find consistency.

Note that Netconf is considering a design that allows multiple syslog
messages to be sent in a netconf notification session. If we used
"]]>]]>" as a syslog message delimiter, we would prevent netconf from
transporting multiple syslog messages, since netconf can only
transport valid XML, and the "]]>]]>" in a syslog message would
indicate the end of an <rpc-reply>, causing netconf to lose
synchronization? See the Montreal Netconf Interim minutes currently
available on the netconf mailing list for more details.

David Harrington
dharrington@huawei.com 
dbharrington@comcast.net
ietfdbh@comcast.net

> -----Original Message-----
> From: Tom Petch [mailto:nwnetworks@dial.pipex.com] 
> Sent: Monday, August 14, 2006 6:36 AM
> To: David Harrington; 'Chris Lonvick'; 'Miao Fuyou'
> Cc: syslog@ietf.org
> Subject: Re: [Syslog] delineated datagrams
> 
> ----- Original Message -----
> From: "David Harrington" <ietfdbh@comcast.net>
> To: "'Chris Lonvick'" <clonvick@cisco.com>; "'Miao Fuyou'" 
> <miaofy@huawei.com>
> Cc: <syslog@ietf.org>; "'Tom Petch'" <nwnetworks@dial.pipex.com>
> Sent: Friday, August 04, 2006 7:59 PM
> Subject: RE: [Syslog] delineated datagrams
> 
> 
> >
> > As you probably know by now, I like to see design reuse 
> across IETF NM
> > solutions, especially across SNMP, syslog, ipfix, and netconf
where
> > feasible.
> >
> > As all the IETF NM protocols move toward similar secure transport
> > solutions, including moving from datagrams to streams, it would be
a
> > good thing to use consistent aproaches to framing.
> >
> > Here is what is happening in the other IETF NM protocols:
> >
> <snip>
>  >
> > The NETCONF protocol uses an RPC-based communication model.
> > From
> >
http://www.ietf.org/internet-drafts/draft-ietf-netconf-prot-12.txt:
> >    NETCONF peers use <rpc> and <rpc-reply> elements to provide
> > transport
> >    protocol-independent framing of NETCONF requests and responses.
> 
> Ok as far as it goes but incomplete.  As the ssh mapping says,
> 
> " As the previous example illustrates, a special character sequence,
>     ]]>]]>, MUST be sent by both the client and the server 
> after each XML
>     document in the NETCONF exchange.  This character sequence
cannot
>     legally appear in an XML document, so it can be 
> unambigiously used to
>     indentify the end of the current document in the event of an XML
>     syntax or parsing error, allowing resynchronization of the
NETCONF
>     exchange."
> .
> Wishing to promote design reuse across IETF NM solutions, 
> especially across the
> character-based ones, I did propose the same separator for 
> syslog over tls and
> still see it as the technically best solution (even though 
> our message content
> can be anything and so, unlike NETCONF, we cannot rely 100% 
> on that not
> appearing in our message content).
> 
> >
> > David Harrington
> > dharrington@huawei.com
> > dbharrington@comcast.net
> > ietfdbh@comcast.net
> >
> 

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