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Re: XML versus SOAP/WSDL Performance



Jon,

In short, I believe (3) ought to be our primary mission.

I believe that XML-based management will eventually be the preferred
approach for all management aspects most of network elements. Therefore, I agree
that it would be short-sighted to impair the future of XML-based approaches in
order to repeat the mistakes of the past.
 
However, I believe that, in the near term, XML will make greatest inroads in
configuration, since, in the past,device configuration has been poorly addressed
by SNMPv1 and SNMPv2.  It is too late for the improvements introduced with
SNMPv3 to change this trend.  

Since SNMP is already the protocol of choice for access to dynamic state,
and since the shortest  development path generally involves reuse of existing
designs and code, and since SNMP will continue to appear on RFP/Qs for
data networking products for some time to come, we will be stuck with dealing
with products that use SNMP for dynamic state access and XML for device
configuration.  That means that EMS/NMS will have to deal with both.

However, I am convinced that the market is moving towards (3), and that
(3) ought to be our primary concern. That doesn't preclude proposing how
the mapping between the optimal XML representation and existing
SNMP naming ought to be accomplished.

/larry

Jon Saperia wrote:
On Monday 23 September 2002 05:07 pm, Larry Menten wrote:
  
Jon and Glenn,

I agree.  XML has much to offer in improving the way data is collected
and asynchronous notifocations are expressed.  Addressing
the need to standardize XML-based configuration, data collection,
and asynchronous messaging recognizes that these are closely related
functions whose standards should be designed together if the full  power
of the approach is to be realized.

I was a little late in subscribing to this list, so I'm sure I missed
some interesting
discussion. (I'll catch up through the archive.)  But if it hasn't been
mentioned already,
the hierarchical representation of both configuration and dynamic data
within
EMS and NMS is better mated to the hierarchical representation of the
data within the network element than the flattened SMI model. 
Management paths that do not do this flattening will be simpler, more
robust, and more powerful.
This holds for the dynamic polled and asynchronous-message acquired data
as well as for configuration data.

Using two different protocols for management adds other complications as
well,
such as the need to administer security (daemons, keys, firewall
protocols, . . . )
twice (when once is bad enough!)

Our system, by the way, also employs XML-expressed transactions for
computational services.  The need goes beyond just access to state.
While I don't suggest that we broaden the charter, we ought to be aware
of the need to accommodate transactions that are not related to
configuration or
to acquisition of dynamic state.

On  the name-mapping issue:
I believe that we will do good if we accommodate
name-mapping from SNMP mibs in some useful way.  In fact, I have had
experience with
management systems in which (symbolic) SNMP object names have been
adopted within the internal object trees that represent the managed
systems.  I expect this is
not uncommon and would like to hear from others who have seen this done.

    

  
I think there are several approaches one could take here:
	1. Provide a mechanism to associate SNMP OIDs with XML-based 
configuration data.  Like you, I have seen this approach. This preserves 
the SNMP infrastructure but has the disadvantages of then requiring two 
infrastructures, SNMP and the XML-based one.  It also suffers from 
problem of mapping between the two, always less efficient.
	2. Leave the problem for later. If this is done, it will probably never 
be solved.
	3. Recognize now the need for a common name space for management and use 
XML for everything.  I like a common infrastructure for everything 
approach. Some do not for legitimate reasons.  The management area needs 
to pick a strategy and go with it. If it is XML fine, just do the whole 
task not a part.

/jon
  
Larry Menten

Jon Saperia wrote:
    
Glenn,

I have mostly been watching this discussion. I wanted to empahsize how
important your comments are from the perspective of building a
management application. The name space problem is a critical problem.
If there is to be a new standard way to configure systems based on
XML, fine. To omit from the basic design of that standard, issues to
deal with all the things we expect from SNMP like asynchronous
messaging and data collection, would be a big mistake.

/jon

On Monday 23 September 2002 11:40 am, Glenn Waters wrote:
      
-----Original Message-----
From: Andy Bierman [mailto:abierman@cisco.com]
Sent: Friday, September 20, 2002 17:34
To: Remco van de Meent
Cc: xmlconf@ops.ietf.org
Subject: Re: XML versus SOAP/WSDL Performance
          
[...]

        
I was one of the people who brought up SNMP and monitoring at the
xmlconf bof...

I think the most important point here is that we have a standard
mechanism to convert SNMP data naming to XML, so an application
can correlate XML and SNMP data.  The ability to use XML for
monitoring is much less important. I would expect that applications
would use XML monitoring for a small amount of data, and continue
to use SNMP monitoring for large, or frequently polled, monitoring
tasks.

Andy
          
Andy, I think that we mostly agree although I think that the ability
to monitor using XML is very important. I believe that XML should be
available to configure, retrieve status, and retrieve statistics. The
reason that I believe this so strongly is that configuration is tied
to status/statistics and that more than one protocol to tie the two
areas together is problematic.

It is problematic since there are almost always fundamental problems
mapping between two naming models. The amount of code and complexity
that is required to map between naming models is non-trivial.

By example, let's say that a routing table entry is configured. One of
the first things that an application may want to do after configuring
the entry is to check the status of the routing table entry. This
means retrieving the status and potentially some statistics. I can't
imagine that a management application would want to configure the
entry one way then switch to another protocol and naming model to get
the statistics. That would just be broken.

Cheers, /gww