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Re: latest beep draft
Hi Andy,
To make my point clear...
If we were to use just the <session-id>, then the schema for hello message
will have to be:
<!--
<hello> element
-->
<xs:complexType name="helloType">
<xs:sequence>
<xs:element ref="capability"/>
<xs:element ref="session-id" minOccurs="0" maxOccurs="1"/>
</xs:sequence>
</xs:complexType>
<xs:element name="hello" type="helloType"/>
With the above schema constraint, the node has no way to guess if
the session-id was omitted by error or by intention (becasue the peer is a
manager).
But, with the following schema constraint, the node will always know the
peer's role (manager/agent)
and can give an error if <session-id> was omitted for the agent role.
<!--
<hello> element
-->
<xs:complexType name="helloType">
<xs:sequence>
<xs:element ref="capability"/>
<xs:element ref="role" minOccurs="1" maxOccurs="1"/>
<xs:element ref="session-id" minOccurs="0" maxOccurs="1"/>
</xs:sequence>
</xs:complexType>
<xs:element name="hello" type="helloType"/>
Thoughts?
-Arvind
----- Original Message -----
From: "Arvind Jamwal" <ajamwal@cisco.com>
To: "Andy Bierman" <ietf@andybierman.com>
Cc: "'Eliot Lear'" <lear@cisco.com>; <sberl@cisco.com>; "'netconf'"
<netconf@ops.ietf.org>
Sent: Friday, April 01, 2005 1:33 AM
Subject: Re: latest beep draft
> Sure, <session-id> would do the trick but I hate the idea of having xml
> elements with overloaded meanings.
>
> Also, I was wondering how you will define a common XML schema for the
hello
> message?
> For the agent, <session-id> element is required and for the manager it is
an
> error to include it.
>
> Having a role element will help.
>
> -Arvind
>
> ----- Original Message -----
> From: "Andy Bierman" <ietf@andybierman.com>
> To: <ajamwal@cisco.com>
> Cc: "'Eliot Lear'" <lear@cisco.com>; <sberl@cisco.com>; "'netconf'"
> <netconf@ops.ietf.org>
> Sent: Thursday, March 31, 2005 12:30 PM
> Subject: Re: latest beep draft
>
>
> > Arvind Jamwal wrote:
> >
> > >Hi Andy,
> > >
> > >Would it make sense to specify the role as part of the hello message
> rather
> > >than relying on the presense/absense of session-id element?
> > >
> > >
> > Why?
> > Can you think of a reason why the <session-id> can't be used?
> > By design, the agent gives out the session ID. This isn't something
> > that can change once decided.
> >
> > The WG already decided that it would be a very rare case (e.g.,
> > misconfiguration)
> > in which an agent connects to another agent or mgr to mgr. And if this
> > ever happens,
> > the worst case scenario is that it uses up 1 TCP control block on an
> > idle connection.
> > That's why the #manager and #agent capabilities were removed from an
> > early draft.
> >
> > Andy
> >
> > >What I am proposing is the following change to the hello message:
> > >
> > > <hello xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
> > > <capabilities>
> > > <capability>
> > > urn:ietf:params:xml:ns:netconf:base:1.0
> > > </capability>
> > > ...
> > > </capabilities>
> > > <role>agent</role> <------- new role element
> > > <session-id>4</session-id>
> > > </hello>
> > >
> > >Comments?
> > >
> > >-Arvind Jamwal
> > >
> > >
> > >
> > >-----Original Message-----
> > >From: owner-netconf@ops.ietf.org [mailto:owner-netconf@ops.ietf.org] On
> > >Behalf Of Andy Bierman
> > >Sent: Tuesday, March 29, 2005 11:29 AM
> > >To: Eliot Lear
> > >Cc: sberl@cisco.com; 'netconf'
> > >Subject: Re: latest beep draft
> > >
> > >Eliot Lear wrote:
> > >
> > >
> > >
> > >>We talked about this. A netconf manager is certainly going to know it
> > >>is a netconf manager and a netconf agent is certainly going to know
> > >>it's a netconf agent. This leaves two cases:
> > >> o where the server is also a client
> > >> o where a client is misconfigured
> > >>
> > >>I think this could be handled with a netconf capability that says
> > >>"iam-manager" or "iam-agent", but as I recall consensus was against
> > >>me. Now, I could introduce that concept as an option in the
> > >><greeting> in the BEEP protocol mappin if there are no objections.
> > >>That would handle the corner case...
> > >>
> > >>
> > >
> > >I don't want special-case handling for BEEP.
> > >Steve already provided the answer -- only a NETCONF peer acting in the
> agent
> > >role should send the <session-id> element in the capabilities exchange.
> If
> > >neither send it or both send it, then the session should be shut down
> > >immediately.
> > >
> > >Andy
> > >
> > >
> > >
> > >>Eliot
> > >>
> > >>Steven Berl (sberl) wrote:
> > >>
> > >>
> > >>
> > >>>Not sure if it is too late for comments on this doc, but here it is
> > >>>anyway.
> > >>>
> > >>>Section 2.1 last paragraph
> > >>>"it is assumed that each knows its role in the conversation."
> > >>>
> > >>>What happens when this assumption is wrong? How is it detected, and
> > >>>what actions are to be taken?
> > >>>
> > >>>If I am a manager and I receive a <rpc> from someone I thought was an
> > >>>agent, what should I do? Probably close the channel.
> > >>>If 2 agents connect to each other, they can exchange <hello> messages
> > >>>and then sit there forever waiting for the other to send an <rpc> of
> > >>>some sort.
> > >>>I suppose the agents could detect this by noticing that the received
> > >>><hello> has a <session-id> element, and that only other agents send
> > >>>this element.
> > >>>The action again should probably be to close the channel.
> > >>>
> > >>>This situation is specific to BEEP because the SSH mapping specifies
> > >>>that only managers can initiate sessions.
> > >>>-steve
> > >>>
> > >>>
> > >>>
> > >>>>-----Original Message-----
> > >>>>From: owner-netconf@ops.ietf.org [mailto:owner-netconf@ops.ietf.org]
> > >>>>On Behalf Of Eliot Lear
> > >>>>Sent: Tuesday, March 22, 2005 1:24 AM
> > >>>>To: netconf
> > >>>>Subject: latest beep draft
> > >>>>
> > >>>>I believe I have addressed issues raised in the WG last call. Can
> > >>>>those who had comments (Juergen, Wes) take a quick scan? In
> particular:
> > >>>>
> > >>>> - addressed security issues regarding SASL & TLS
> > >>>> - added examples - are these enough?
> > >>>> - clarified use of <hello> and <greeting>
> > >>>>
> > >>>>The draft is at the following URL and is still relatively short:
> > >>>>
> > >>>>http://www.ietf.org/internet-drafts/draft-ietf-netconf-beep-04.txt
> > >>>>
> > >>>>Eliot
> > >>>>
> > >>>>
> >
> >
> > --
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> > the word 'unsubscribe' in a single line as the message text body.
> > archive: <http://ops.ietf.org/lists/netconf/>
>
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