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Computing in Network Research Group                               P. Liu
Internet-Draft                                                    H. Yao
Intended status: Informational                                   L. Geng
Expires: January 11, 2021                                   China Mobile
                                                           July 10, 2020


              Differential Computing Resource Reservation
               draft-liu-coin-differential-reservation-00

Abstract

   Computing in the network may require the embedded computing
   capability in the network device, such as gateway, switch, etc, and
   there might be so much distributed computing task in the network.
   Some new applications like AR/VR, motion control put forward higher
   demand of network than before, and AI is also considered to be used
   in the app and network.

   In order to satisfy their demands, network may not only need to
   reserve bandwidth resource, but also reserve computing resource.
   This document analyzes the requirements of Serial distributed
   computing model and give some reference solutions.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

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 January 11, 2021.





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Copyright Notice

   Copyright (c) 2020 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
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   (https://trustee.ietf.org/license-info) in effect on the date of
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Existing Protocol . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Resource Reservation Protocol . . . . . . . . . . . . . .   3
     2.2.  Path Computation Element Protocol . . . . . . . . . . . .   3
   3.  Problems of Resource Reservation  . . . . . . . . . . . . . .   4
   4.  Reference Method  . . . . . . . . . . . . . . . . . . . . . .   5
     4.1.  Distributed Resource Reservation  . . . . . . . . . . . .   5
     4.2.  Centralized Resource Reservation  . . . . . . . . . . . .   6
       4.2.1.  PCEP  . . . . . . . . . . . . . . . . . . . . . . . .   7
       4.2.2.  Netconf/Yang  . . . . . . . . . . . . . . . . . . . .   7
   5.  Conclusion  . . . . . . . . . . . . . . . . . . . . . . . . .   8
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Overview

   From cloud computing to edge computing, computing power is
   distributed to the customer side.  In the future network and
   computing convergence system, computing power will be distributed as
   ubiquitous endogenous resources in each node of the network.  The
   user's request can be satisfied by calling the nearest node resource,
   which is no longer limited to a specific node.

   Resource reservation is usually used to guarantee the QoS of specific
   application traffic.  The reservation of network resources is same in
   an end-to-end path, which means the reserved bandwidth resources will
   not change from the client to the server, but computing is different.
   Distributed computing will bring different computing power, and
   different resources need to be reserved for different nodes.  For



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   example, AI algorithm now has a model of step-by-step iteration at
   multiple nodes.  The previous iteration will affect the next
   calculation results, and the computing resources required for each
   iteration are not the same.  From the perspective of network
   standard, we hope to regard computing resources as the dimensions to
   measure network performance, such as the same bandwidth, path, etc.,
   while the traditional technologies of resource reservation have not
   considered the reservation of computing resources, and have not
   considered the differentiated resource reservation model.

2.  Existing Protocol

   Existing resource reservation protocols, such as Resource ReSerVation
   Protocol(RSVP) and Path Computation Element Protocol (PCEP) , can be
   used to reserve bandwidth resources.  RSVP is a traditional protocol,
   which only focuses on how to initiate the reservation of resources,
   not the establishment of path.  Later, RSVP-TE protocol was developed
   for MPLS.  PCEP was designed to separate the path calculation and
   path establishment functions of RSVP-TE firstly, which means that the
   path calculation part before resource reservation can be realized.
   Therefore, RSVP and PCEP can be used together or separately.

2.1.  Resource Reservation Protocol

   Resource reservation is currently regarded as the key technology
   configuration scheme to guarantee network QoS.  In order to solve the
   problem of bandwidth competition caused by the simultaneous arrival
   of specific data flow and common data flow on the network node, the
   bandwidth reservation management of data from the source node to the
   destination node end-to-end is realized, so as to ensure the real-
   time data flow QoS and delay requirements.  The general process is as
   follows:

   The sender client initiates the request of resource reservation by
   the path message.  After determining the path, the sender sends the
   request along the path, carrying the network requirements (latency,
   etc.) to the receiver.

   The receiver calculates the bandwidth and other resources that need
   to be reserved for the network according to the request of the
   sender.  Then it returns according to the original path, and informs
   the equipment to reserve resources one by one.

2.2.  Path Computation Element Protocol

   Path Computation Element Protocol (PCEP) is a centralized
   configuration technology, which is usually used in software defined
   network (SDN) as the South interface calculation and configuration



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   path information.  PCE can improve the agility of the network.  Any
   change in network can be programmed using PCECC to learn the change
   and react to it quickly and efficiently.

   PEC can initiate resource reservation application to each device in
   the path by the PCLRResv message.  This message is sent by Path
   Computation Element (PCE) to Path Computation Client (PCC) to sent
   reserved label range for the network.  The objects supported in this
   message are stateful PCE request parameters objects, setting the
   unique identifier for mapping request/response between PCEP and PCC.

3.  Problems of Resource Reservation

   In the model of computing in the network, the computing resource may
   be distributed in multiple nodes.  A task may be divided into several
   parts to be executed by multiple nodes, including serial distribution
   and parallel distribution.  Parallel distribution can reserve
   resources separately.  However, in the serial computing model, the
   calculation process of serial distribution algorithm is sequential,
   and the results of the previous calculation need to be used in the
   later calculation, so it will bring the following two problems:

   Different computing nodes on the same path need different reserved
   computing resources.

   The bandwidth resources to be reserved maybe different after the
   previous calculations in the same path.

   A typical example is the artificial intelligence algorithm, which
   involves the multi-layer convolution iterative process and can be
   completed by multiple computing device in serial.  As shown in the
   figure, 20%, 30% and 50% tasks are calculated on network device 1, 3
   and server respectively, and the calculation results of device 1 will
   affect the subsequent calculation of device 3 and server.  Then,

   Network device 1, 3 and server need to reserve corresponding
   computing resources respectively.

   Since devices 1 and 3 calculated, the traffic will change after
   passing through devices 1 and 3, so the bandwidth resources to be
   reserved are different.

   Traditional RSVP and other protocols do not consider the calculation
   attribute, so the reserved value of bandwidth resource along the path
   is unchanged, and the calculation resource cannot be reserved.  PCEP
   also dosen't consider about the comuputing resource.





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     +------+                                                +--------+
     |Client|                                              ->| Server |
     +------+ \   +--------+   +--------+   +--------+    /  +--------+
               \->|network |   |network |   |network |->/      50% of
                  |device 1|-->|device 2|-->|device 3|        computing
                  +--------+   +--------+   +--------+          tasks
                    20% of                    30% of
                  computing                  computing
                    tasks                     tasks

                    Serial distributed computing model

4.  Reference Method

   This scheme provides distributed and centralized resource reservation
   reference scheme.  It should be noted that for serial distributed
   computing, we assume that the application side implements the
   following functions:

   The number of steps are involved in the calculation.

   The computing proportion of calculation required at each node.

   For bandwidth changes after each step of calculation, if this item
   cannot be implemented, the same bandwidth resources will be reserved
   by default.

4.1.  Distributed Resource Reservation

   Distributed resource reservation can be implemented by extending RSVP
   or RSVP-TE protocol.  The server receives the client's service
   request, calculating the resource reservation strategy and return it.
   The process is as follows:

   1.  The client sends the service request, carrying the service
   requirements and the collected resource status of each node on the
   path.  They will be collected and added to the information that
   carried by the service request.

   2.  The server receives the client's service request, then generates
   the resource reservation strategy for target nodes on the path based
   on the the service requirements and the resource status of each node,
   and return the resource reservation strategy to each target node
   along the path to reserve the resource.

   The resource status at least includes the computing resource status
   such as the catergery of chip, algorithm, etc.  It can also includes
   the network resource status such as bandwidth, delay, etc.



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   The resource reservation strategy at least includes the computing
   resource reservation information of target nodes, which is as
   follows:

   1.  Determine the serial distributed computing subtasks and computing
   resources required by each computing subtask based on the service
   request.

   2.  Select the target nodes for each computing subtask and generate
   the computing resources reservation information to inform each target
   node to reserve resource based on the computing resource status of
   each node and the computing resources required by each computing
   subtask.

   Moreover, if the bandwidth change after each subtask can be
   calculated, the resource reservation strategy can also carrying the
   bandwidth resources reservation information.

   It can be realized by defining new object of RSVP or RSVP-TE to
   reserve different resources in each target nodes.  The object can be
   customized and extended with variable length.  For example,
   redefining a new class num as 30, carries the following message body:

   [L = 0, IPv4, 64, IP address1, bandwidth 1, computing resource 1]

   [L = 0, IPv4, 64, IP address2, bandwidth 2, computing resource 2]

   [L = 0, IPv4, 64, IP address3, bandwidth 3, computing resource 3]

   [L = 0, IPv4, 64, IP address4, bandwidth 4, computing resource 4]

   ......

   It should be noted that the extended object can not only carry the
   collected resources status of each node in the PATH message, but also
   return the resource reservation strategy in the RESV message.

4.2.  Centralized Resource Reservation

   Centralized resource reservation can be realized by the network
   manager.  The manager receives the service request, calculates the
   network and computing resources needed, and initiates resource
   reservation configuration for the target nodes along the path.The
   process is as follows:

   The client sends a service request to the network manager.





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   Network manager selects the path according to the service request and
   get the resource status of each node on the path.

   Network manager generates the resource reservation strategy based on
   the client's service request and resource status of each node.

   Network manager sends resource reservation strategy to target nodes
   to reserve the resource.

   The resource status at least includes the computing resource status.
   The resource reservation strategy at least includes the computing
   resource reservation information of each target node.  Which are the
   same with chapter 4.1.

   If at least one node in the selected path does not meet the resource
   reservation requirements, it is necessary to re-select at least one
   node in the path and get the resource status of the re-selected node
   until the path meets the requirements of the resource reservation
   strategy.

4.2.1.  PCEP

   By adding calculation force resource reservation field to resource
   reservation object in PECP message, each calculation force flow has a
   dynamic resource range based on the minimum reserved resource.

     +---------+---------+-----------+----------+--------+
     | Object  | Label   | Reserverd |Interface |  In/   |
     | Type    | ID      | Bandwidth |IP Address|  Out   |
     +---------+---------+-----------+----------+--------+

                              PCEP extension

4.2.2.  Netconf/Yang

   It can also send resource reservation configuration to the target
   nodes by netconf and defining the Yang structure.  The reference Yang
   module is as follows.













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   module: rs-computing-network
     +--rw rs-computing-network
        +--rw added-device[id]
        |  +--rw service id         string
        |  +--rw user id            string
        |  +--rw bandwitdh            mbps
        |  +--rw computing resource    tbd
        +--rw deleted-device[id]

                                Yang Module

5.  Conclusion

   The draft proposes a method of differential reservation of computing
   power and bandwidth resources.  Because the traditional network does
   not include computing power, the reservation of network resources is
   the same on the path.  This scheme can accurately reserve computing
   power and network resources for the serial distributed computing
   services.  It also present the reference methods to realize different
   resource reservation.Of course, there may be more and more
   appropriate methods to achieve serial distributed computing power and
   network resource reservation, which may require more analysis and
   discussion.

6.  Security Considerations

   TBD.

7.  IANA Considerations

   TBD.

8.  Normative References

   [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>.

   [RFC5440]  Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
              Element (PCE) Communication Protocol (PCEP)", RFC 5440,
              DOI 10.17487/RFC5440, March 2009,
              <https://www.rfc-editor.org/info/rfc5440>.








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Authors' Addresses

   Peng Liu
   China Mobile
   Beijing  100053
   China

   Email: liupengyjy@chinamobile.com


   Huijuan Yao
   China Mobile
   Beijing  100053
   China

   Email: yaohuijuan@chinamobile.com


   Liang Geng
   China Mobile
   Beijing  100053
   China

   Email: gengliang@chinamobile.com



























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