Internet DRAFT - draft-zhou-intarea-aware-route-san-database

draft-zhou-intarea-aware-route-san-database







INTAREA                                                          F. Zhou
Internet-Draft                                                   D. Yuan
Intended status: Standards Track                         ZTE Corporation
Expires: 27 April 2023                                           D. Yang
                                             Beijing Jiaotong University
                                                         24 October 2022


 Computing Status Awareness, Advertisement and Service Routing methods
                       Based on Databases of SAN
             draft-zhou-intarea-aware-route-san-database-00

Abstract

   This draft proposes a unified method to perceive and advertise the
   running status of computing resources in a Service Awareness Network
   by introducing a distributed database.  The forwarding operation in a
   fine-grained service routing policy is correspondingly defined which
   is completely decoupled from conventional IP routing.  In the scheme
   proposed, the impact of high frequency changes of computing resources
   is avoided and the compatibility of the network is enhanced.

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
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   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on 27 April 2023.

Copyright Notice

   Copyright (c) 2022 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights



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   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   4
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  The Perception of the Status of Computing Resources . . . . .   5
   5.  The Advertisement of the Status of Computing Resources  . . .   6
   6.  Service Routing Decoupled from IP Routing . . . . . . . . . .   7
   7.  Use Case  . . . . . . . . . . . . . . . . . . . . . . . . . .   9
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  10
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
   11. Normative References  . . . . . . . . . . . . . . . . . . . .  10
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   With computing resource continuously migrating to edges, services
   residing distributedly turns to be delivered in a dynamic way.  More
   fine-grained networking policies awaring of service SLA requirements
   are urgently required.

   As illustrated in [I-D.huang-service-aware-network-framework], a
   typical SAN framework consists of service client, service server, SAN
   ingress, SAN relay and SAN egress.  A fine-grained networking policy
   can be achieved through successive procedures:

   *  The perception of the status of computing resources: Changes and
      variations in the current status of computing resources should be
      notified and reflected.  Static configurations together with the
      dynamic changes comprise a thorough and overall view as a
      reference to select a proper resource pool.

   *  The advertisement of the status of computing resources: A group of
      nodes in the network domain should further be aware of the current
      distributions and conditions among various resource pools so that
      the networking and routing policies can be adjusted or formulated.
      The advertisement of the running status is also a learning
      procedure for the network domain.







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   *  The formulation of a specific service routing policy: With the
      knowledge of the running status and network conditions, an
      appropriate resource pool can be selected to satisfy the service
      SLA requirements.  A specific fine-grained service routing policy
      can further be formulated to forward the packets.

   The mentioned procedures are shown in Figure 1:


                               (1)Perception<---------------------+
                                      |                           |
                                      v                           |
                              (2)Advertisement                    |
                                      |                  Status of|
                      +---------------+--------------+   Computing|
                      |               |              |   Resources|
                      v               v              v            |
                                                                  |
         (3)Service Routing                                       |
   +-------+ -------->                                        +-------+
   |Service|    +-----------+   +----------+   +----------+   |Service|
   |       +----+SAN Ingress+---+SAN  Relay+---+SAN egress+---+       |
   |Client |    +-----------+   +----------+   +----------+   |Server |
   +-------+          |                                       +-------+
       |              |                                           |
       |              |                                           |
       |              |<-----SAN Fowarding and Routing Domain---->|
       |                                                          |
       |                                                          |
       |<---------------Service Identification Domain------------>|


      Figure 1: Computing Resource Perception and Advertisement in SAN


   Since the perception and advertisement procedures are the premises to
   achieve service routing, enabling the network to be aware of the
   running status timely is regarded to be a significant problem.

   Currently, the perception of computing resources can be commonly
   achieved by application protocols, FTP for instance.  With the
   connection between clients and the server establishd, the cloud side
   is required to spontaneously upload the running status of computing
   resources.  The process of advertising computing resource information
   is commonly fulfilled by extending IGP or BGP.  Packets with a
   designated format carrying information of computing resources flood
   in the network to complete the learning process.




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   In current schemes, service routing is strongly coupled with
   traditional IP routing which results in the following deficiencies:

   *  The status of computing resources is updated with delay attributed
      to a relatively long authentication duration and the usage of
      multiple protocols.

   *  Responses in the network to the highly dynamic computing resources
      is relatively slow by using IGP or BGP.

   *  Compared to conventional IP routing, service routing is
      comprehensively designated by both network metrics and service SLA
      requirements in which the status of computing resources is highly
      dynamic.  Thus, advertising the dynamic status emerge a large
      amount of extra packets and exert relatively severe impact on the
      traffic bearer in the current network.  Furthermore, conventional
      network services are not concerned about the status of computing
      resource.

   According to the analysis above, the following problems are required
   to be solved:

   *  Reduce the overwhelmed utilization of L3 protocols and improve the
      compatibility of the network.

   *  Simplify the perception and advertisement process and optimize the
      learning procedure of updated status.

   This draft proposes computing resources perception and advertisement
   method by introducing a distributed database to fulfill service
   routing decoupled from conventional IP routing.

2.  Requirements Language

   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.

3.  Terminology

   *  LB: Load Balancer

   *  FTP: File Transfer Protocol

   *  IGP: Interior Gateway Protocol




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   *  BGP: Border Gateway Protocol

   *  DB-Agent: Agent of a database

   *  GW: Gateway

   *  SLA: Service Level Agreements

   *  SID: Segment ID

   *  SAN: Service Awareness Network

   *  SAN ID: Service Awareness Network Identification, an
      identification designed to indicate the fundamental and common
      service types

4.  The Perception of the Status of Computing Resources

   The computing resources information of the cloud-side server is used
   to reflect the performance and a running status of resource pools.
   It is obtained to facilitate unified collaborative invocation of
   computing power resources.

   It is noted that identical services can be provided by multiple
   resource pools which connects to different gateways and status of
   resource pools varies from each other.  Thus, the description of
   computing resource may include the following attributes as shown in
   Figure 2:


   +------------+-----------------+-----------------------------------+
   |   SAN ID   | Service Gateway |  Service Descriptions Index(1-n)  |
   +------------+-----------------+-----------+-----------+-----------+
   | Service  1 |       GW1       |   CPU 1   | Memory  1 |   O/I 1   |
   +------------+-----------------+-----------+-----------+-----------+
   | Service  2 |       GW2       |   CPU 2   | Memory  2 |   O/I 2   |
   +------------+-----------------+-----------+-----------+-----------+
   | Service  3 |       GW2       |   CPU 3   | Memory  3 |   O/I 3   |
   +------------+-----------------+-----------+-----------+-----------+
   | Service  3 |       GW3       |   CPU 4   | Memory  4 |   O/I 4   |
   +------------+-----------------+-----------+-----------+-----------+
   | Service  1 |       GW3       |   CPU 5   | Memory  5 |   O/I 5   |
   +------------+-----------------+-----------+-----------+-----------+








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               Figure 2: Status Table of Computing Resources


   Since the status of computing resources can be modeled as a
   collection of key-value pairs with keys as unique identifiers, this
   draft introduced a distributed database to store and update the
   running status.  As shown in Figure 2, a service identification
   defined as a SAN ID(Service ID) in
   [I-D.ma-intarea-identification-header-of-san] to represent a globally
   unique service semantic identification and its connected gateway
   should be configured as the key for the extracted data model.

   A distributed system has the advantages of advanced performance, high
   availability and simple extensibility.  It is highly partitionable
   and allows horizontal scaling which satisfies the practical scenarios
   of large scale of service instances.  Also, both keys and values can
   be anything from simple objects to complex compound objects, and thus
   heterogeneous computing resources can be described and stored.

   After the key-value pairs are extracted and further written into the
   database by the cloud side as multiple DB-Agents, the perception of
   the status of computing resources is fulfilled.

5.  The Advertisement of the Status of Computing Resources


   +-------------+
   |   +--------+|                      +-----------------------------+
   |VM |Database||<---------------------|           DB-Agent          |
   |   +--------+|        Write         |                             |
   +-------------+                      |                 +---------+ |
          | Read                        |        +--------+Service 1| |
          v                             |        |        +---------+ |
   +----------------------+             | +------+------+             |
   |       DB-Agent       |             | |Load Balancer|   ......    |
   |                      |             | +------+------+             |
   | +----+        +----+ |             |        |        +---------+ |
   | |PE 1| ...... |PE n| |             |        +--------+Service n| |
   | +----+        +----+ |             |                 +---------+ |
   |                      |             |                             |
   | Network Edge Devices |             |             Cloud           |
   +----------------------+             +-----------------------------+









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      Figure 3: The status of computing resources learning procedures


   With the introduction of a distributed database, the data of the
   computing resources can be stored in hierarchically organized
   directories.  A typical form is described as below:

   *  /service instances/GW

   *  /service instances/SAN ID

   *  /service instances/SAN ID/CPU Load

   *  /service instances/SAN ID/Memory Remains

   As shown in Figure 3, a group of edge devices in the network domain
   observes the key value information through a publish-subscribe
   mechanism.  Specific keys or directories can be watched for changes
   and multiple clients can react to changes in values.  Since multiple
   edge devices simultaneously observe the variations, the running
   status is advertised to all edge devices.  It is concluded that, by
   introducing a database, functions of perception and advertisement are
   unified.

   It can be understood that in the mentioned writing and reading
   process, there is no necessity to perform additional authentication
   on a management protocol and network layer protocols, thereby
   simplifying the overall procedure.

6.  Service Routing Decoupled from IP Routing





















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    +-----------------------------+
    |           DB-Agent          |
    |+---------------------------+|
    ||    Computing Resource &   ||
    ||    Network  Information   ||
    ||     Perception  Module    ||
    |+---------------------------+|
    +-----------------------------+
                  |                    +-------------------------+
                  |<-------------------|    Networking Policy    |
                  |                    +-------------------------+
                  |                    +-------------------------+
                  |<-------------------|Service Addressing Policy|
                  |                    +-------------------------+
                  v
      +-----------------------+                    +------------------+
      | Service Routing Table +<------------------>+ IP Routing Table |
      +-----------------------+                    +------------------+


            Figure 4: Service Routing Decoupled from IP Routing


   As shown in Figure 4, after the current computing status is obtained,
   a proper resource pool can be selected to satisfy the service SLA
   requirements, so as to quickly and accurately guide data forwarding.
   Together with path metrics in the network, a specific service routing
   table is formulated.

   Since the service routing table is generated additionally, it is
   completely decoupled from the conventional IP routing table.  As
   shown in Figure 5, for services with requirements for computing
   resources, the service routing table maps to the IP routing table to
   complete a forwarding operation.  With the service gateway
   determined, an Interface IP or an SRv6 policy can be indexed.  For
   conventional services which are not sensitive to computing resources,
   a forwarding operation can be implemented simply in the original way.














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         Service Routing Table                 IP Routing Table
   +------------+-----------------+    +---------------+--------------+
   | Service ID | Service Gateway |    |Prefix(Gateway)|   Next Hop   |
   +------------+-----------------+    +---------------+--------------+
   | Service  1 | GW1 (Node SID1) |<-->|      GW1      | Interface IP |
   +------------+-----------------+    +---------------+--------------+
   | Service  2 | GW2 (Node SID2) |    |               | SRv6  Policy |
   +------------+-----------------+<-->|      GW2      |  (Endpoint+  |
   | Service  3 | GW2 (Node SID2) |    |               |    Color)    |
   +------------+-----------------+    +---------------+--------------+


          Figure 5: Service Routing Table Maps to IP Routing Table


   With the introduction of a distributed database, the service routing
   procedure is decoupled from traditonal IP routing which enhances the
   compatibility of different services carried in the network.

7.  Use Case

   As shown in Figure 6, suppose CPU load is a sample attribute and 70%
   is configured to be a threshold.  If the CPU load beyonds 70%, the
   traffic needs to be steered to another satisfied resource pool .

   The procedure of learning and processing updated computing resource
   status is described as follows:

   *  The CPU load of the container or VM where the service instance is
      located reaches the threshold 70% and the updated status is then
      written into the database in a key-value model.

   *  Edge devices in the network domain subscribe the information by
      watching the prefix of the key-value pair.

   *  Any variations in the subscribed information can be perceived and
      further learned by the edge devices.

   *  Learning the CPU load reaches 70%, the service routing table is
      updated or regenerated.











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         Network Domain                             Cloud Domain
   +-------------------------+                +-----------------------+
   |+------------+ +--------+|   +--------+   |+--------+ +----------+|
   ||Edge Devices| |DB-Agent||   |Database|   ||DB-Agent| |Cloud Side||
   |+------------+ +--------+|   +--------+   |+--------+ +----------+|
   +-------------------------+                +-----------------------+
           |            |             |<-------------|           |
           |            |             |              |           |
           |            |  watch      | (/Service    |           |
           |            |  (/Service  | Instances/   |           |
           |            |  Instances  | CPU Load 70) |           |
           |            |  prefix/)   |              |           |
           |            |------------>|              |           |
           |            |             |              |           |
           |            |<------------|              |           |
           |            |  notify     |              |           |
           |notify      |  (/Service  |              |           |
           |(/Service   |  Instances  |              |           |
           |Instances/  |  prefix/)   |              |           |
           |SAN ID/     |             |              |           |
           |CPU Load 70)|             |              |           |
           |<-----------|             |              |           |
           |            |             |              |           |


         Figure 6: An Example of Database-Based Computing Resource
                            Perception Procedure


8.  Security Considerations

   TBA

9.  Acknowledgements

   TBA

10.  IANA Considerations

   TBA

11.  Normative References









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   [I-D.huang-service-aware-network-framework]
              Huang, D. and B. Tan, "Service Aware Network Framework",
              Work in Progress, Internet-Draft, draft-huang-service-
              aware-network-framework-00, 24 May 2022,
              <https://www.ietf.org/archive/id/draft-huang-service-
              aware-network-framework-00.txt>.

   [I-D.ma-intarea-identification-header-of-san]
              Ma, L., Zhou, F., Li, H., and D. Yang, "Service
              Identification Header of Service Aware Network", Work in
              Progress, Internet-Draft, draft-ma-intarea-identification-
              header-of-san-00, 24 October 2022,
              <https://datatracker.ietf.org/api/v1/doc/document/draft-
              ma-intarea-identification-header-of-san/>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <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,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

Authors' Addresses

   Fenlin Zhou
   ZTE Corporation
   No.50 Software Avenue
   Nanjing
   Jiangsu, 210012
   China
   Email: zhou.fenlin@zte.com.cn


   Dongyu Yuan
   ZTE Corporation
   No.50 Software Avenue
   Nanjing
   Jiangsu, 210012
   China
   Email: yuan.dongyu@zte.com.cn









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   Dong Yang
   Beijing Jiaotong University
   No.3 Shangyuancun Haidian District
   Beijing
   100044
   China
   Email: dyang@bjtu.edu.cn












































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