Internet-Draft Network Anomaly Semantics July 2024
Graf, et al. Expires 8 January 2025 [Page]
Workgroup:
NMOP
Internet-Draft:
draft-netana-nmop-network-anomaly-semantics-02
Published:
Intended Status:
Experimental
Expires:
Authors:
T. Graf
Swisscom
W. Du
Swisscom
A. Huang Feng
INSA-Lyon
V. Riccobene
Huawei
A. Roberto
Huawei

Semantic Metadata Annotation for Network Anomaly Detection

Abstract

This document explains why and how semantic metadata annotation helps to test, validate and compare outlier detection, supports supervised and semi-supervised machine learning development, enables data exchange among network operators, vendors and academia and make anomalies for humans apprehensible. The proposed semantics uniforms the network anomaly data exchange between and among operators and vendors to improve their network outlier detection systems.

Discussion Venues

This note is to be removed before publishing as an RFC.

Discussion of this document takes place on the Operations and Management Area Working Group Working Group mailing list (nmop@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/nmop/.

Source for this draft and an issue tracker can be found at https://github.com/network-analytics/draft-netana-nmop-network-anomaly-semantics/.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on 8 January 2025.

1. Introduction

[I-D.netana-nmop-network-anomaly-architecture] provides an overall introduction into how anomaly detection is being applied into the IP network domain and which operational data is needed. It approaches the problem space by automating what a Network Engineer would normally do when verifying a network connectivity service. Monitor from different network plane perspectives to understand wherever one network plane affects another negatively.

In order to fine tune outlier detection as described in [I-D.netana-nmop-network-anomaly-lifecycle], the results provided as analytical data need to be reviewed by a Network Engineer. Keeping the human out of the monitoring but still involving him in the alert verification loop.

This document describes what information is needed to understand the output of the outlier detection for a Network Engineer, but also at the same time is semantically structured that it can be used for outlier detection testing by comparing the results systematically and set a baseline for supervised machine learning which requires labeled operational data.

2. Conventions and Definitions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

2.1. Terminology

This document defines the following terms:

Message Broker: is an intermediary software component that translates messages from the formal messaging protocol of the sender to the formal messaging protocol of the receiver routed in topics. Message brokers are elements in Data Mesh where software applications communicate by exchanging formally-defined messages.

Stream Catalog: provides a single point of access that allows users to centrally search semantics for information across a Message Broker.

Additionally it makes use of the terms defined in [I-D.netana-nmop-network-anomaly-architecture] and [I-D.ietf-nmop-terminology].

The following terms are used as defined in [I-D.netana-nmop-network-anomaly-architecture]:

  • Outlier

The following terms are used as defined in [I-D.ietf-nmop-terminology]:

3. Observed Symptoms

In this section observed network symptoms are specified and categorized according to the following scheme:

Action:

Which action the network node performed for a packet in the Forwarding Plane, a path or adjacency in the Control Plane or state or statistical changes in the Management Plane. For Forwarding Plane we distinguish between missing, where the drop occurred outside the measured network node, drop and on-path delay, which was measured on the network node. For Control Plane we distinguish between reachability, which refers to a change in the routing or forwarding information base (RIB/FIB) and adjacency which refers to a change in peering or link-layer resolution. For Management Plane we refer to state or statistical changes on interfaces.

Reason:

For each action, one or more reasons describe why this action was used. For Drops in Forwarding Plane we distinguish between Unreachable because network layer reachability information was missing, Administered because an administrator configured a rule preventing the forwarding for this packet and Corrupt where the network node was unable to determine where to forward to due to packet, software or hardware error. For on-path delay we distinguish between Minimum, Average and Maximum Delay for a given flow. For Control Plane wherever a the reachability was updated or withdrawn or the adjacency was established or teared down. For Management Plane we distinguish between interfaces states up and down, and statistical errors, discards or unknown protocol counters.

Cause:

For each reason one or more cause describe the cause why the network node has chosen that action.

Table 1 consolidates for the forwarding plane a list of common symptoms with their Actions, Reasons and Causes.

Table 1: Describing Symptoms and their Actions, Reason and Cause for Forwarding Plane
Action Reason Cause
Missing Previous Time
Drop Unreachable next-hop
Drop Unreachable link-layer
Drop Unreachable Time To Life expired
Drop Unreachable Fragmentation needed and Don't Fragment set
Drop Administered Access-List
Drop Administered Unicast Reverse Path Forwarding
Drop Administered Discard Route
Drop Administered Policed
Drop Administered Shaped
Drop Corrupt Bad Packet
Drop Corrupt Bad Egress Interface
Delay Min -
Delay Mean -
Delay Max -

Table 2 consolidates for the control plane a list of common symptoms with their actions, reasons and causess.

Table 2: Describing Symptoms and their Actions, Reason and Cause for Control Plane
Action Reason Cause
Reachability Update Imported
Reachability Update Received
Reachability Withdraw Received
Reachability Withdraw Peer Down
Reachability Withdraw Suppressed
Reachability Withdraw Stale
Reachability Withdraw Route Policy Filtered
Reachability Withdraw Maximum Number of Prefixes Reached
Adjacency Established Peer
Adjacency Established Link-Layer
Adjacency Locally Teared Down Peer
Adjacency Remotely Teared Down Peer
Adjacency Locally Teared Down Link-Layer
Adjacency Remotely Teared Down Link-Layer
Adjacency Locally Teared Down Administrative
Adjacency Remotely Teared Down Administrative
Adjacency Locally Teared Down Maximum Number of Prefixes Reached
Adjacency Remotely Teared Down Maximum Number of Prefixes Reached
Adjacency Locally Teared Down Transport Connection Failed
Adjacency Remotely Teared Down Transport Connection Failed

Table 3 consolidates for the management plane a list of common symptoms with their Actions, Reasons and Causes.

Table 3: Describing Symptoms and their Actions, Reason and Cause for Management Plane
Action Reason Cause
Interface Up Link-Layer
Interface Down Link-Layer
Interface Errors -
Interface Discards -
Interface Unknown Protocol -

4. Semantic Metadata

Metadata adds additional context to data. For instance, in networks the software version of a network node where Management Plane metrics are obtained from as described in[I-D.claise-opsawg-collected-data-manifest]. Where in Semantic Metadata the meaning or ontology of the annotated data is being described. In this section a YANG model is defined in order to provide a structure for the metadata related to anomalies happening in the network. The module is intended to describe the metadata used to "annotate" the operational data collected from the network nodes, which can include time series data and logs, as well as other forms of data that is "time-bounded". The aspects discussed so far in this document are grouped under the concept of "anomaly" which represents a collection of symptoms. The anomaly overall has a set of parameters that describe the overall behavior of the network in a given time-window including all the spotted symptoms (network anomalies).

4.1. Overview of the Model for the Symptom Semantic Metadata

Figure 2 contains the YANG tree diagram [RFC8340] of the Figure 1 which augments the [RFC8343] defined ietf-interfaces and the Figure 3.

For each symptom, the following parameters have been assigned: A unique ID for identification, a description of the symptom, a list of affected metrics or counters, start and end time to specify the time-window, a confident score indicating how accurate the symptom was detected, a concern score indicating how critical the symptom is, the annotator indicating if it has been identified by a network expert or an algorithm, the tags with key value where Action, Reason and Cause can be annotated as described in previous section.

<CODE BEGINS> file "ietf-interfaces-with-symptoms@2024-06-29.yang"

module ietf-interfaces-with-symptoms {
    yang-version 1.1;
    namespace "http://example.org/example-ietf-interfaces-with-symptoms";
    prefix "ifws";

    import ietf-symptom-semantic-metadata {
        prefix "sm";
    }
    import ietf-interfaces {
        prefix "if";
    }

    revision 2024-06-29 {
        description
          "Initial version";
        reference
          "Example: Symptoms Annotated IETF Interface";
    }

    augment "/if:interfaces/if:interface" {
        description
        "Augment interfaces with symptoms";
        uses sm:symptom-group;
    }
    augment "/if:interfaces-state/if:interface" {
        description
         "Augment interfaces with symptoms";
        uses sm:symptom-group;
  }
}

<CODE ENDS>
Figure 1: ietf-interfaces-with-symptoms Example YANG Module
module: ietf-interfaces
  +--rw interfaces
  |  +--rw interface* [name]
  |     +--rw name                        string
  |     +--rw description?                string
  |     +--rw type                        identityref
  |     +--rw enabled?                    boolean
  |     +--rw link-up-down-trap-enable?   enumeration {if-mib}?
  |     +--ro admin-status                enumeration {if-mib}?
  |     +--ro oper-status                 enumeration
  |     +--ro last-change?                yang:date-and-time
  |     +--ro if-index                    int32 {if-mib}?
  |     +--ro phys-address?               yang:phys-address
  |     +--ro higher-layer-if*            interface-ref
  |     +--ro lower-layer-if*             interface-ref
  |     +--ro speed?                      yang:gauge64
  |     +--ro statistics
  |     |  +--ro discontinuity-time    yang:date-and-time
  |     |  +--ro in-octets?            yang:counter64
  |     |  +--ro in-unicast-pkts?      yang:counter64
  |     |  +--ro in-broadcast-pkts?    yang:counter64
  |     |  +--ro in-multicast-pkts?    yang:counter64
  |     |  +--ro in-discards?          yang:counter32
  |     |  +--ro in-errors?            yang:counter32
  |     |  +--ro in-unknown-protos?    yang:counter32
  |     |  +--ro out-octets?           yang:counter64
  |     |  +--ro out-unicast-pkts?     yang:counter64
  |     |  +--ro out-broadcast-pkts?   yang:counter64
  |     |  +--ro out-multicast-pkts?   yang:counter64
  |     |  +--ro out-discards?         yang:counter32
  |     |  +--ro out-errors?           yang:counter32
  |     +--rw ifws:symptom
  |        +--rw ifws:id?                        yang:uuid
  |        +--rw ifws:event-id?                  yang:uuid
  |        +--rw ifws:description?               string
  |        +--rw ifws:start-time?                yang:date-and-time
  |        +--rw ifws:end-time?                  yang:date-and-time
  |        +--rw ifws:confidence-score?          score
  |        +--rw ifws:concern-score?             score
  |        +--rw ifws:tags* [key]
  |        |  +--rw ifws:key      string
  |        |  +--rw ifws:value    string
  |        +--rw (ifws:pattern)?
  |        |  +--:(ifws:drop)
  |        |  |  +--rw ifws:drop                 empty
  |        |  +--:(ifws:spike)
  |        |  |  +--rw ifws:spike                empty
  |        |  +--:(ifws:mean-shift)
  |        |  |  +--rw ifws:mean-shift           empty
  |        |  +--:(ifws:seasonality-shift)
  |        |  |  +--rw ifws:seasonality-shift    empty
  |        |  +--:(ifws:trend)
  |        |  |  +--rw ifws:trend                empty
  |        |  +--:(ifws:other)
  |        |     +--rw ifws:other                string
  |        +--rw ifws:annotator
  |           +--rw (ifws:annotator-type)
  |           |  +--:(ifws:human)
  |           |  |  +--rw ifws:human        empty
  |           |  +--:(ifws:algorithm)
  |           |     +--rw ifws:algorithm    empty
  |           +--rw ifws:name?              string
  x--ro interfaces-state
     x--ro interface* [name]
        x--ro name               string
        x--ro type               identityref
        x--ro admin-status       enumeration {if-mib}?
        x--ro oper-status        enumeration
        x--ro last-change?       yang:date-and-time
        x--ro if-index           int32 {if-mib}?
        x--ro phys-address?      yang:phys-address
        x--ro higher-layer-if*   interface-state-ref
        x--ro lower-layer-if*    interface-state-ref
        x--ro speed?             yang:gauge64
        x--ro statistics
        |  x--ro discontinuity-time    yang:date-and-time
        |  x--ro in-octets?            yang:counter64
        |  x--ro in-unicast-pkts?      yang:counter64
        |  x--ro in-broadcast-pkts?    yang:counter64
        |  x--ro in-multicast-pkts?    yang:counter64
        |  x--ro in-discards?          yang:counter32
        |  x--ro in-errors?            yang:counter32
        |  x--ro in-unknown-protos?    yang:counter32
        |  x--ro out-octets?           yang:counter64
        |  x--ro out-unicast-pkts?     yang:counter64
        |  x--ro out-broadcast-pkts?   yang:counter64
        |  x--ro out-multicast-pkts?   yang:counter64
        |  x--ro out-discards?         yang:counter32
        |  x--ro out-errors?           yang:counter32
        +--ro ifws:symptom
           +--ro ifws:id?                        yang:uuid
           +--ro ifws:event-id?                  yang:uuid
           +--ro ifws:description?               string
           +--ro ifws:start-time?                yang:date-and-time
           +--ro ifws:end-time?                  yang:date-and-time
           +--ro ifws:confidence-score?          score
           +--ro ifws:concern-score?             score
           +--ro ifws:tags* [key]
           |  +--ro ifws:key      string
           |  +--ro ifws:value    string
           +--ro (ifws:pattern)?
           |  +--:(ifws:drop)
           |  |  +--ro ifws:drop                 empty
           |  +--:(ifws:spike)
           |  |  +--ro ifws:spike                empty
           |  +--:(ifws:mean-shift)
           |  |  +--ro ifws:mean-shift           empty
           |  +--:(ifws:seasonality-shift)
           |  |  +--ro ifws:seasonality-shift    empty
           |  +--:(ifws:trend)
           |  |  +--ro ifws:trend                empty
           |  +--:(ifws:other)
           |     +--ro ifws:other                string
           +--ro ifws:annotator
              +--ro (ifws:annotator-type)
              |  +--:(ifws:human)
              |  |  +--ro ifws:human        empty
              |  +--:(ifws:algorithm)
              |     +--ro ifws:algorithm    empty
              +--ro ifws:name?              string

Figure 2: YANG tree diagram for ietf-symptom-semantic-metadata

4.2. YANG Module

The YANG module has one typdef defining the score and a grouping which can be augmented.

<CODE BEGINS> file "ietf-symptom-semantic-metadata@2024-06-29.yang"

module ietf-symptom-semantic-metadata {
    yang-version 1.1;
    namespace "urn:ietf:params:xml:ns:yang:ietf-symptom-semantic-metadata";
    prefix sm;

    import ietf-yang-types {
        prefix yang;
        reference
          "RFC 6991: Common YANG Data Types";
    }

  organization "IETF NMOP (Network Management Operations) Working Group";
  contact
    "WG Web:   <http:/tools.ietf.org/wg/netconf/>
     WG List:  <mailto:nmop@ietf.org>

     Authors:  Thomas Graf
               <mailto:thomas.graf@swisscom.com>
               Wanting Du
               <mailto:wanting.du@swisscom.com>
               Alex Huang Feng
               <mailto:alex.huang-feng@insa-lyon.fr>
               Vincenzo Riccobene
               <mailto:vincenzo.riccobene@huawei-partners.com>
               Antonio Roberto
               <mailto:antonio.roberto@huawei.com>";
    description
        "This module defines symptom objects to be used by a network
         anomaly detection system. The defined objects can be used to
         augment operational network collected observability data and
         analytical problem data equally. Describing the observed
         symptoms, confidence and concern scores and outlier patterns.

         Copyright (c) 2023 IETF Trust and the persons identified as
         authors of the code.  All rights reserved.

         Redistribution and use in source and binary forms, with or
         without modification, is permitted pursuant to, and subject
         to the license terms contained in, the Revised BSD License
         set forth in Section 4.c of the IETF Trust's Legal Provisions
         Relating to IETF Documents
         (https://trustee.ietf.org/license-info).

         This version of this YANG module is part of RFC XXXX; see the RFC
         itself for full legal notices.";

    revision 2024-06-29 {
        description
          "Initial version";
        reference
          "RFC XXX: Semantic Metadata Annotation for Network Anomaly Detection";
    }

    typedef score {
      type uint8 {
        range "0 .. 1";
      }
    }

    grouping symptom-group {
        container symptom {
            leaf id {
                type yang:uuid;
                description
                    "Unique ID of the symptom type";
            }
            leaf event-id {
                type yang:uuid;
                description "Reference to the network event this symptom is part of";
            }
            leaf description {
                type string;
                description
                    "Textual description of the symptom";
            }
            leaf start-time {
                type yang:date-and-time;
                description
                    "Date and time indicating the beginning of the symptom";
            }
            leaf end-time {
                type yang:date-and-time;
                description
                    "Date and time indicating the end of the symptom";
            }
            leaf confidence-score {
                type score;
            }
            leaf concern-score {
                type score;
            }
            list tags {
                key "key";
                leaf key {
                    type "string";
                    mandatory "true";
                }
                leaf value {
                    type "string";
                    mandatory "true";
                }
            }
            choice pattern {
                mandatory "false";
                description
                    "Network Plane affected by the symptom";
                case drop {
                    leaf drop {
                        mandatory "true";
                        type empty;
                    }
                }
                case spike {
                    leaf spike {
                        mandatory "true";
                        type empty;
                    }
                }
                case mean-shift {
                    leaf mean-shift {
                        mandatory "true";
                        type empty;
                    }
                }
                case seasonality-shift {
                    leaf seasonality-shift {
                        mandatory "true";
                        type empty;
                    }
                }
                case trend {
                    leaf trend {
                        mandatory "true";
                        type empty;
                    }
                }
                case other {
                    leaf other {
                        type string;
                        mandatory "true";
                        description "specify the type";
                    }
                }
            }
            container annotator {
                choice annotator-type {
                    mandatory "true";
                    case human {
                        leaf human {
                            mandatory "true";
                            type empty;
                        }
                    }
                    case algorithm {
                        leaf algorithm {
                            mandatory "true";
                            type empty;
                        }
                    }
                }
                leaf name {
                    mandatory "false";
                    type string;
                }
            }
        }
    }
}

<CODE ENDS>
Figure 3: ietf-symptom-semantic-metadata YANG Module

5. Security Considerations

The security considerations.

6. Implementation status

This section provides pointers to existing open source implementations of this draft. Note to the RFC-editor: Please remove this before publishing.

6.1. Antagonist

A tool called Antagonist has been implemented during the IETF 119 Hackathon, in order to validate the application of the YANG models defined in this draft. Antagonist provides visual support for two important use cases in the scope of this document:

  • the generation of a ground truth in relation to symptoms and problems in timeseries data
  • the visual validation of results produced by automated network anomaly detection tools.

The open source code can be found here: [Antagonist]

7. Acknowledgements

The authors would like to thank xxx for their review and valuable comments.

8. References

8.1. Normative References

[Antagonist]
Riccobene, V., Roberto, A., Du, W., Graf, T., and H. Huang Feng, "Antagonist: Anomaly tagging on historical data", <https://github.com/vriccobene/antagonist>.
[I-D.ietf-nmop-terminology]
Davis, N., Farrel, A., Graf, T., Wu, Q., and C. Yu, "Some Key Terms for Network Incident and Problem Management", Work in Progress, Internet-Draft, draft-ietf-nmop-terminology-01, , <https://datatracker.ietf.org/doc/html/draft-ietf-nmop-terminology-01>.
[I-D.netana-nmop-network-anomaly-architecture]
Graf, T., Du, W., and P. Francois, "An Architecture for a Network Anomaly Detection Framework", Work in Progress, Internet-Draft, draft-netana-nmop-network-anomaly-architecture-00, , <https://datatracker.ietf.org/api/v1/doc/document/draft-netana-nmop-network-anomaly-architecture/>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
[RFC8340]
Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, , <https://www.rfc-editor.org/info/rfc8340>.
[RFC9232]
Song, H., Qin, F., Martinez-Julia, P., Ciavaglia, L., and A. Wang, "Network Telemetry Framework", RFC 9232, DOI 10.17487/RFC9232, , <https://www.rfc-editor.org/info/rfc9232>.

8.2. Informative References

[I-D.claise-opsawg-collected-data-manifest]
Claise, B., Quilbeuf, J., Lopez, D., Martinez-Casanueva, I. D., and T. Graf, "A Data Manifest for Contextualized Telemetry Data", Work in Progress, Internet-Draft, draft-claise-opsawg-collected-data-manifest-06, , <https://datatracker.ietf.org/doc/html/draft-claise-opsawg-collected-data-manifest-06>.
[I-D.ietf-ippm-pam]
Mirsky, G., Halpern, J. M., Min, X., Clemm, A., Strassner, J., and J. François, "Precision Availability Metrics for Services Governed by Service Level Objectives (SLOs)", Work in Progress, Internet-Draft, draft-ietf-ippm-pam-09, , <https://datatracker.ietf.org/doc/html/draft-ietf-ippm-pam-09>.
[I-D.ietf-opsawg-ipfix-on-path-telemetry]
Graf, T., Claise, B., and A. H. Feng, "Export of On-Path Delay in IPFIX", Work in Progress, Internet-Draft, draft-ietf-opsawg-ipfix-on-path-telemetry-07, , <https://datatracker.ietf.org/api/v1/doc/document/draft-ietf-opsawg-ipfix-on-path-telemetry/>.
[I-D.netana-nmop-network-anomaly-lifecycle]
Riccobene, V., Roberto, A., Graf, T., Du, W., and A. H. Feng, "Experiment: Network Anomaly Lifecycle", Work in Progress, Internet-Draft, draft-netana-nmop-network-anomaly-lifecycle-02, , <https://datatracker.ietf.org/doc/html/draft-netana-nmop-network-anomaly-lifecycle-02>.
[RFC4364]
Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, , <https://www.rfc-editor.org/info/rfc4364>.
[RFC5102]
Quittek, J., Bryant, S., Claise, B., Aitken, P., and J. Meyer, "Information Model for IP Flow Information Export", RFC 5102, DOI 10.17487/RFC5102, , <https://www.rfc-editor.org/info/rfc5102>.
[RFC7011]
Claise, B., Ed., Trammell, B., Ed., and P. Aitken, "Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of Flow Information", STD 77, RFC 7011, DOI 10.17487/RFC7011, , <https://www.rfc-editor.org/info/rfc7011>.
[RFC7270]
Yourtchenko, A., Aitken, P., and B. Claise, "Cisco-Specific Information Elements Reused in IP Flow Information Export (IPFIX)", RFC 7270, DOI 10.17487/RFC7270, , <https://www.rfc-editor.org/info/rfc7270>.
[RFC7854]
Scudder, J., Ed., Fernando, R., and S. Stuart, "BGP Monitoring Protocol (BMP)", RFC 7854, DOI 10.17487/RFC7854, , <https://www.rfc-editor.org/info/rfc7854>.
[RFC8343]
Bjorklund, M., "A YANG Data Model for Interface Management", RFC 8343, DOI 10.17487/RFC8343, , <https://www.rfc-editor.org/info/rfc8343>.
[RFC9418]
Claise, B., Quilbeuf, J., Lucente, P., Fasano, P., and T. Arumugam, "A YANG Data Model for Service Assurance", RFC 9418, DOI 10.17487/RFC9418, , <https://www.rfc-editor.org/info/rfc9418>.

Authors' Addresses

Thomas Graf
Swisscom
Binzring 17
CH-8045 Zurich
Switzerland
Wanting Du
Swisscom
Binzring 17
CH-8045 Zurich
Switzerland
Alex Huang Feng
INSA-Lyon
Lyon
France
Vincenzo Riccobene
Huawei
Dublin
Ireland
Antonio Roberto
Huawei
Dublin
Ireland