Subject: Re: [OPSAWG] CALL FOR ADOPTION: draft-www-opsawg-yang-vpn-service-pm

From: "Adrian Farrel" <[email-masked]>
Date: Tue, 2 Feb 2021 23:08:55 -0000

Hi Joe,

I think this document fills a hole in the set of YANG models we have for
managing and operating services over our network, and I'd like the WG to
pick it up and polish it.

I commit to doing a review or two as the draft advances. To kick that 
off there are a few comments below. None of these needs to be addressed
before adoption.

Best,
Adrian

---

It is unclear to me from Section 1 whether this document is intended to
be limited to L3VPNs or applies to all VPNs. The very first sentence 
gives a strong hint that the scope is restricted to L3VPN, but I think
that is not the intention.

---

Maybe Figure 1 should be set in the context of RFC 8309. In particular,
s/Service Network Models/Network Service Models/
But it might also be nice to include a reference to 8309 to help give
meaning to the figure.

---

Looking at...
          +--ro inbound-octets?             yang:counter64
          +--ro inbound-unicast?            yang:counter64
          +--ro inbound-nunicast?           yang:counter64
          +--ro inbound-discards?           yang:counter32
          +--ro inbound-errors?             yang:counter32
          +--ro inbound-unknown-protocol?   yang:counter32
          +--ro outbound-octets?            yang:counter64
          +--ro outbound-unicast?           yang:counter64
          +--ro outbound-nunicast?          yang:counter64
          +--ro outbound-discards?          yang:counter32
          +--ro outbound-errors?            yang:counter32

I tend to agree that there are likely to be an order of magnitude fewer
discards and errors than legitimate packets, but I can also consider
times (such as during attacks) then every packet is in error or is
discarded. I think it would be wise (and possibly helpful) to have all
of the counters at 64bits.

This would also mean that the four counters under loss-statistics should
also be counter64.

-----Original Message-----
From: OPSAWG <[email-masked]> On Behalf Of Joe Clarke (jclarke)
Sent: 29 January 2021 14:18
To: [email-masked]
Subject: [OPSAWG] CALL FOR ADOPTION: draft-www-opsawg-yang-vpn-service-pm

Hello, WG.  The draft-www-opsawg-yang-vpn-service-pm (A YANG Model for
Network and VPN Service Performance Monitoring) work has been steadily
progressing with the other VPN network model work.  This was presented
last at IETF 109
(https://datatracker.ietf.org/doc/slides-109-opsawg-a-yang-model-for-network
-and-vpn-service-performance-monitoring/),
and there has been some recent discussion on list that has been
addressed by the authors.  We would like to know if the working group
wants to formally adopt this work.

Please respond with your comments and thoughts on the draft.  We will
conduct a two week CFA, concluding on February 12, 2021.

Joe (on behalf of co-chairs)

_______________________________________________
OPSAWG mailing list
[email-masked]
https://www.ietf.org/mailman/listinfo/opsawg

---

From: "Wei Wang" <[email-masked]>
Date: Wed, 3 Feb 2021 13:10:52 +0800

Hi all，
&nbsp; &nbsp; I have read this draft and I support the adoption.

Best Regards,
Wei

------------------&nbsp;Original&nbsp;------------------
From:                                                                                                                        "Joe Clarke (jclarke)"                                                                                    <jclarke=[email-masked]&gt;;
Date:&nbsp;Fri, Jan 29, 2021 10:18 PM
To:&nbsp;"[email-masked]"<[email-masked]&gt;;

Subject:&nbsp;[OPSAWG] CALL FOR ADOPTION: draft-www-opsawg-yang-vpn-service-pm

Hello, WG.&nbsp; The draft-www-opsawg-yang-vpn-service-pm (A YANG Model for
Network and VPN Service Performance Monitoring) work has been steadily
progressing with the other VPN network model work.&nbsp; This was presented
last at IETF 109
(https://datatracker.ietf.org/doc/slides-109-opsawg-a-yang-model-for-network-and-vpn-service-performance-monitoring/),
and there has been some recent discussion on list that has been
addressed by the authors.&nbsp; We would like to know if the working group
wants to formally adopt this work.

Please respond with your comments and thoughts on the draft.&nbsp; We will
conduct a two week CFA, concluding on February 12, 2021.

---

From: Dhruv Dhody <[email-masked]>
Date: Thu, 4 Feb 2021 15:42:49 +0530

Hi,

The work seems to be quite useful. I support adoption by the WG.

A few comments -

(1) If the model supports L2VPN, I think we need to add the L2-level
counters in the vpn-summary-statistics. Currently we only have IPv4 and
IPv6 routes.

(2) Section 3

   The performance monitoring information reflecting the quality of the
   Network or VPN service such as end to end network performance data
   between source node and destination node in the network or between
   VPN sites can be aggregated or calculated using, for example, PCEP
   solution [RFC8233] [RFC7471] [RFC8570] [RFC8571] or LMAP [RFC8194].

I suggest changing "PCEP" to more generic term "Traffic Engineering
Database (TED)".

(3) Section 3.2

3.2.  On demand Retrieval via RPC Model

   To obtain a snapshot of a large amount of performance data from a
   network element (including network controllers), service-assurance
   applications may use polling-based methods such as RPC model to fetch
   performance data on demand.

Do you mean the usual Netconf <get>? Not sure about the term "RPC model".
Maybe refer to it as just polling mechanism.

(4) Section 4.1

I am not sure about the depiction of how PE map to CE and further map to
Nodes in the underlying network in Figure 3.

In the YANG we have node-type that can be PE, CE, or P and this figure does
not help. Its possible I might be seeing it wrong :)

Also the mapping in the figure and the text for Node 3 and 4 don't match.

In "Site-2 A and B play the role of hub while Site-2 C plays the role of
spoke.", did you intend to have 2 hub and 1 spoke?

(5) Section 4.2

   For network performance monitoring, the attributes of "Network Level"
   that defined in [RFC8345] do not need to be extended.

[RFC8345] does not use the term "Network Level". I am wondering if we
should use the full path /nw:networks/nw:network/ or container name
instead...

Also applicable to 4.3

The "vpn-id" is just a string and would also depend on the
network-service-type (L3VPN, L2VPN); IMHO some text to describe this is
needed.

(6) Section 4.3

Not clear on why node-type is marked as (Attribute) but site-id and
site-role are (Constraint).

Can you expand on "site-id", is this matching with L3SM site-id or L3NM's
vpn-network-access?

The type should be yang:counter32 instead of uint32 for -

       +--rw vpn-summary-statistics
          +--rw ipv4
          |  +--rw total-routes?          uint32
          |  +--rw total-active-routes?   uint32
          +--rw ipv6
             +--rw total-routes?          uint32
             +--rw total-active-routes?   uint32

(7) Section 7

(a)

  identity link-type {
    base vpn-common:protocol-type;
    description
      "Base identity for link type, e.g.,GRE, MPLS TE, VXLAN.";
  }

  identity VXLAN {
    base link-type;
    description
      "Base identity for VXLAN Tunnel.";
  }

  identity ip-in-ip {
    base link-type;
    description
      "Base identity for IP in IP Tunnel.";
  }

What is the benefit of creating link-type as an identity? Can VXLAN and
ip-in-ip directly use vpn-common:protocol-type as a base?

(b)

    leaf outbound-qlen {
      type uint32;
      description
        " Length of the queue of the interface from where
          the packet is forwarded out.  The queue depth could
           be the current number of memory buffers used by the
          queue and a packet can consume one or more memory buffers
          thus constituting device-level information.";
    }
    description
      "Grouping for interface service telemetry.";
  }

Since these are abstract nodes how do we know this information?

(c)

    leaf reference-time {
      type yang:date-and-time;
      description
        "The time that the current Measurement Interval started.";
    }

Shouldn't this be config false?

==

Suggestion:

Can we add an example of how percentile is used and reported in the
appendix?

Hope you find these comments useful.

Thanks!
Dhruv

On Fri, Jan 29, 2021 at 7:49 PM Joe Clarke (jclarke) <jclarke=
[email-masked]> wrote:

> (
> https://datatracker.ietf.org/doc/slides-109-opsawg-a-yang-model-for-network-and-vpn-service-performance-monitoring/
> ),

---

From: "[email-masked]" <[email-masked]>
Date: Fri, 5 Feb 2021 09:05:00 +0800

Hi, folks,
As described in RFC8969, network performance monitoring is one Indispensable component of closed loop service lifecycle management.  The model defined in draft-www-opsawg-yang-vpn-service-pm  is one typical example of network as a service model and NaaS is crucial to service deployment automation. So I support the adoption of this work.
Best regards
Chongfeng

[email-masked]
 
From: Joe Clarke \(jclarke\)
Date: 2021-01-29 22:18
To: [email-masked]

---

From: "Joe Clarke (jclarke)" <[email-masked]>
Date: Wed, 17 Feb 2021 14:28:44 +0000

The call for adoption has closed, and there has been sufficient interest
expressed and comments posted for the WG to adopt this work.

Authors, please resubmit this draft changing _only_ the name to
draft-ietf-opsawg-yang-vpn-service-pm-00.  When doing so, make sure you
choose that this new draft replaces draft-www-opsawg-yang-vpn-service-pm.

Thanks.

Joe