Re: [i2rs] draft-chen-i2rs-identifier-management-00

["Susan Hares" <[e-mail]>]

Andy: 

 

I missed the second part of the email  (http://www.ietf.org/mail-archive/web/i2rs/current/msg02532.html) in my earlier message: 

 

>. " The last paragraph sounds like some nodes will be accepted and others rejected.

>If any nodes are rejected, the entire edit should be rejected.

 

RESTCONF does an atomic action within a http session.   NETCONF within a commit.  Section 6.2 of the I2RS architecture document describes state storage for I2RS, and it does not have the atomic requirement for the protocol.  Instead section 3.3 of the I2RS architecture document calls for this to be model driver.  Let me provide examples from the 2 major I2RS protocol independent models: 

 

The I2RS RIB yang model (draft-ietf-i2rs-rib-data-model-00 <https://tools.ietf.org/html/draft-ietf-i2rs-rib-data-model-00> )  proposes that each route will be associated with the following: route preference, active, installed.  Notifications for route change will be given if route is installed, active, and a reason given, or if the route commit fails. Some routes may be accepted, and some routes rejected for installation to the RIB.   The concept is the client will be able to detect when a route is rejected.  

 

The draft-ietf-i2rs-yang-network-topo-00 states in section 3.5 discusses the challenge that topology models are not: configuration data only or operational data only – but a combination of both in ephemeral state.  Draft-ietf-i2rs-yang-network-topo-00 suggests an ephemeral topology model which is operational (read-only) that contains data from: a) only read from operational units, b) a configured topology, and c) combination topology (operational state and configured).  (A second alternative is to just have “a” and “b”, but for now let’s focus on a, b, and c).  The “C” combination topology may be generated based on priority of configured topology versus operational data.  The inclusion in “c” may also be validated (E.g. interface up, or L3 link runs on tunnel over interface which is up)).  

 

These two model documents show why atomic state may be on a very small section of the whole change.  

 

> I don’t think the rule-list should store the client priority.

> It should be in the 'group' list, or outside NACM completely."

 

Your alternate proposal are: 

 

1)            Moving i2rs-priority to group list 

2)            Adding a i2rs-client [unspecified location] 

 

This mail deals with #1.  If you have more details on proposal #2, please suggest them on the list.  

 

list i2rs-client {

      key name;

      leaf name {

         description "The client name";

         type i2rs:client-name;

      }

      leaf priority {

        description "The priority value assigned to this client.";

        type i2rs:client-priority;

     }

  }

 

Question: Is this i2rs-list to be included in the group list for NACM (as listed below from RFC6536) as a leaf list below? 

 

       container groups {

         description

           "NETCONF Access Control Groups.";

 

         list group {

          key name;

           description

             "One NACM Group Entry.  This list will only contain

              configured entries, not any entries learned from

              any transport protocols.";

 

           leaf name {

             type group-name-type;

             description

               "Group name associated with this entry.";

           }

 

           leaf-list user-name {

             type user-name-type;

             description

               "Each entry identifies the username of

                a member of the group associated with

                this entry.";

           }

          # add leaf-list I2rs-client here 

         }

       }

Your message: http://www.ietf.org/mail-archive/web/i2rs/current/msg02523.html

States:  "I think I2RS interaction with NACM needs to be clearly defined. NACM implementations do not currently check write requests

on config=false data. It is possible some edits to NACM are needed even if no objects are added to the data structure."

 

Do you have a proposal for changing the text in section 5.2 of draft-haas-i2rs-ephemeral-state-reqs-00?  

Is it sufficient to state:   “NACM implementations for I2RS will need to check write request on config=false, ephemeral = true. “

before the paragraph: 

 

“Ephemeral configuration state nodes that are created or altered by users that match a rule carrying i2rs-priority will have those nodes annotated with metadata.  Additionally, during commit processing, if nodes are found where i2rs-priority is already present, and the  priority is better than the transaction's user's priority for that node, the commit SHALL fail. An appropriate error should be returned

   to the user stating the nodes where the user had insufficient

   priority to override the state.

 

I’m unclear what this means: “It is possible some edits to NACM are needed even if no objects are added to the data structure."

 

Sue 

 

-----Original Message-----
From: Andy Bierman [mailto:[e-mail]] 
Sent: Thursday, May 28, 2015 8:23 PM
To: Susan Hares
Cc: Juergen Schoenwaelder; Joel M. Halpern; Jeffrey Haas; [e-mail]; [e-mail]; Alia Atlas
Subject: Re: [i2rs] draft-chen-i2rs-identifier-management-00

 

On Thu, May 28, 2015 at 5:09 PM, Susan Hares < <mailto:[e-mail]> [e-mail]> wrote:

> Andy:

> 

> Thank you for your question.  Let me precise.

> 

> Jeff proposes that clients specify the priority mechanism is an attribute that is stored in the NACM list on the agent (see Section 5.2 as described in the draft-haas-i2rs-ephemeral-state-reqs-00 (quoted below).   The client-Agent identities are load in a mechanism which is out-of-band from the I2RS protocol these values.  Into the Client, the Agent's ID is loaded.  Into the Agent, the valid client's identity is loaded along with the client's priority.  AAA (Radius/Diameter) is an example of an out-of-band mechanism to pass the information with.  IMU (in my understanding), the NACM on the agent is created based on this AAA loading.  The i2rs secondary identity is loaded via an edit-config mechanism in a config operation (see section 5.1 of Jeff's document.).  Please let me know if my understanding of NACM creation based on AAA input is correct.

> 

 

That is an optional mode.

There is also a local users table that can be used.

 

 

> I2RS Module Nodes (E.g. I2RS RIB routes) are written within an Agent will be annotated with meta-data with the client-id, priority, and secondary ID.

> 

> The only proposed change to section 5.2 requirements is to the 

> sentence "Additionally, during commit processing, if

>    nodes are found where i2rs-priority is already present, and the

>    priority is better than the transaction's user's priority for that

>    node, the commit SHALL fail.

> 

> " Additionally, during commit processing" is incorrect because there is not commit processing.   Jeff stated we are still working with both NETCONF and RESTCONF - so we must allow for a commit process.  In the meeting I noted that the architecture indicates a change is possible only if the priority is greater than (>) existing priority.  (First rather than last).  Therefore this text should read:  "Additionally, during the operation (RESTCONF)/Commit (NETCONF) processing, if the nodes are found where i2rs-priority is already present, and the priority is equal to or better than the transaction's user's priority for the node, the operation/commit SHALL fail."

> 

> Do you have any suggestions for modifications to section 5 of Jeff's document?

> 

> Sue

> 

> ============================

> Jeff's document 5.2 states:

> 

>   To support Multi-Headed Control, I2RS requires that there be a

>    decidable means of arbitrating the correct state of data when

>    multiple clients attempt to manipulate the same piece of data.  This

>    is done via a priority mechanism with the highest priority winning.

>    This priority may vary on a per-node or sub-tree basis based for a

>    given identity.

> 

>    This further implies that priority is an attribute that is stored in

>    the NETCONF Access Control Model [RFC6536] as part of a rule-list.

>    E.g.:

> 

>    Ephemeral configuration state nodes that are created or altered by

>    users that match a rule carrying i2rs-priority will have those nodes

>    annotated with metadata.  Additionally, during commit processing, if

>    nodes are found where i2rs-priority is already present, and the

>    priority is better than the transaction's user's priority for that

>    node, the commit SHALL fail.  An appropriate error should be returned

>    to the user stating the nodes where the user had insufficient

>    priority to override the state.

> 

 

 

The last paragraph sounds like some nodes will be accepted and others rejected.

If any nodes are rejected, the entire edit should be rejected.

 

I don;t think the rule-list should store the client priority.

It should be in the 'group' list, or outside NACM completely.

 

 

Andy

 

> 

> 

> -----Original Message-----

> From: Andy Bierman [ <mailto:[e-mail]> mailto:[e-mail]]

> Sent: Thursday, May 28, 2015 7:40 PM

> To: Susan Hares

> Cc: Juergen Schoenwaelder; Joel M. Halpern; Jeffrey Haas; 

>  <mailto:[e-mail]> [e-mail];  <mailto:[e-mail]> [e-mail]; Alia Atlas

> Subject: Re: [i2rs] draft-chen-i2rs-identifier-management-00

> 

> On Thu, May 28, 2015 at 4:22 PM, Susan Hares < <mailto:[e-mail]> [e-mail]> wrote:

>> Andy:

>> 

>> Yes - the client with priority and secondary identity are inherently simple additions.   Can you confirm my understanding below based on Jeff's document?

>> 

> 

> Not sure what you mean.

> i don't think the client should provide the priority in request messages.

> This is configured on the agent, not requested by the client.

> 

> 

>> Can you explain  your statement "I do not want to change NETCONF or RESTCONF to use client priority?"  What are you proposing that you do not want to add the NACM list the priority?

> 

> I don't want to change NETCONF and RESTCONF so that config=true objects use priority.  Only I2RS should use it.

> 

>> 

>> Sue

> 

> Andy

> 

>> ===============

>> 

>> Example

>> ------------------------

>> 1) any multiple TCP sessions from a client application will use a different ID if they want a different priority for write of an object

>>              Application 1:  TCP session 1 -  priority 1,  secondary-identity  "pub-sub monitor"

>>              Application 1:  TCP session 2 - priority 10, secondary-identity "tracing monitor"

>>         Application 1:  TCP session 3 -  priority 20, opaque "Weekly config"

>>         Application 1:  TCP session 4 -  priority 55, opaque "Emergency config"

>> 

>> Jeff's META-data  example:

>> 

>>   <foo xmlns:i2rs=" <https://ietf.example.com/i2rs> https://ietf.example.com/i2rs"

>>         i2rs:i2rs-secondary-identity="user1" i2rs:i2rs-priority="47">

>>        ...

>>    </foo>

>> 

>> For my example TCP session 1

>>    <foo xmlns:i2rs="http:s//ietf.example.com/i2rs"

>>         I2rs:i2rs-secondary-identity="pub-sub montior"

>> i2rs:i2rs-priority="1">

>> 

>> Juergen's client example:

>> 

>>     list i2rs-client {

>>        key name;

>>       leaf name {

>>          description "The client name";

>>          type i2rs:client-name;

>>        }

>>        leaf priority {

>>           description "The priority value assigned to this client.";

>>          type i2rs:client-priority;

>>       }

>>     }

>> 

>>    +--rw rule-list [name]

>>       +--rw name     string

>>       +--rw group*   union

>>       +--rw rule [name]

>>          +--rw name string

>>          +--rw module-name?  union

>>          +--rw (rule-type)?

>>          |  +--:(protocol-operation)

>>          |  |  +--rw rpc-name?  union

>>          |  +--:(notification)

>>          |  |  +--rw notification-name?  union

>>          |  +--:(data-node)

>>          |     +--rw path node-instance-identifier

>>          +--rw access-operations?  union

>>          +--rw action action-type

>>          +--rw comment?  string

>>          +--rw i2rs:i2rs-priority i2rs-priority-type

>> 

>> Are you proposing something different than Jeff's proposal?

>> 

>> Sue

>> 

>> -----Original Message-----

>> From: Andy Bierman [ <mailto:[e-mail]> mailto:[e-mail]]

>> Sent: Thursday, May 28, 2015 11:17 AM

>> To: Juergen Schoenwaelder; Andy Bierman; Joel M. Halpern; Jeffrey 

>> Haas;  <mailto:[e-mail]> [e-mail];  <mailto:[e-mail]> [e-mail]; Alia Atlas; Susan Hares

>> Subject: Re: [i2rs] draft-chen-i2rs-identifier-management-00

>> 

>> On Wed, May 27, 2015 at 11:05 PM, Juergen Schoenwaelder < <mailto:[e-mail]> [e-mail]> wrote:

>>> On Wed, May 27, 2015 at 06:04:58PM -0700, Andy Bierman wrote:

>>>> 

>>>> Although I should be promoting use of NACM, I am not so sure it 

>>>> should be mandatory for I2RS or required to configure I2RS client priority.

>>>> 

>>>>    list i2rs-client {

>>>>       key name;

>>>>       leaf name {

>>>>          description "The client name";

>>>>          type i2rs:client-name;

>>>>       }

>>>>       leaf priority {

>>>>         description "The priority value assigned to this client.";

>>>>         type i2rs:client-priority;

>>>>      }

>>>>   }

>>> 

>>> So what is i2rs:client-name - is it any different from a 

>>> NETCONF/RESTCONF username?

>>> 

>> 

>> Is is probably not different.

>> 

>> 

>>> NACM maps user names into groups and NACM allows to have the mapping 

>>> supplied by an external source (e.g. RADIUS). If this priority 

>>> mapping is kept separate from NACM, would we need to provision means 

>>> to get the priority from AAA as well?

>>> 

>> 

>> My point showing the 2 item list is that the information needed to implement I2RS client priority is rather trivial.

>> It can certainly be made really complicated by the IETF, but it is an inherently trivial configuration.

>> 

>>> And the bigger question: Do we create something specific for I2RS or 

>>> are we going to extend the generic YANG/NC/RC framework to provide 

>>> the tools I2RS needs? This is probably a question the NETCONF WG has 

>>> to answer.

>> 

>> It is good to make reusable features.

>> I don't want to change NETCONF or RESTCONF to use client priority.

>> Let I2RS prove it is useful first.  I am not convinced it will really help.

>> It seems like an implementation detail that is being turned into ad administrative task.  If multiple clients from multiple vendors are stepping on each other, then the likely outcome of a priority change by the administrator will be to select which clients should continue working and which should be broken.

>> 

>> 

>>> 

>>> /js

>>> 

>> 

>> Andy

>> 

>>> --

>>> Juergen Schoenwaelder           Jacobs University Bremen gGmbH

>>> Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany

>>> Fax:   [phone]         < <http://www.jacobs-university.de/> http://www.jacobs-university.de/>

>> 

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