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Versions: (draft-hares-i2rs-usecase-reqs-summary) 00 01 02 03

i2rs                                                            S. Hares
Internet-Draft                                                    Huawei
Intended status: Informational                                   M. Chen
Expires: May 19, 2017                                Huawei Technologies
                                                       November 15, 2016


                 Summary of I2RS Use Case Requirements
                draft-ietf-i2rs-usecase-reqs-summary-03

Abstract

   The I2RS Working Group (WG) has described a set of use cases that the
   I2RS systems could fulfil.  This document summarizes these use cases.
   It is designed to provide requirements that will aid the design of
   the I2RS architecture, Information Models, Data Models, Security, and
   protocols.

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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   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 May 19, 2017.

Copyright Notice

   Copyright (c) 2016 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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   include Simplified BSD License text as described in Section 4.e of




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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Protocol Independent Use Case Requirements  . . . . . . . . .   4
   3.  BGP Use Case Requirements . . . . . . . . . . . . . . . . . .   6
   4.  IGP Use Cases . . . . . . . . . . . . . . . . . . . . . . . .   8
   5.  CCNE Use Cases  . . . . . . . . . . . . . . . . . . . . . . .  10
   6.  Topology Related Use Cases  . . . . . . . . . . . . . . . . .  11
     6.1.  Virtual Connection Use Case Requirements  . . . . . . . .  11
     6.2.  Virtual Network Use Case Requirements . . . . . . . . . .  11
     6.3.  Topology Use Case . . . . . . . . . . . . . . . . . . . .  13
     6.4.  Virtual Topology Data Model . . . . . . . . . . . . . . .  17
     6.5.  Virtual Topology IP Data Model  . . . . . . . . . . . . .  19
     6.6.  Virtual Topology Network Element  . . . . . . . . . . . .  19
   7.  Requirements from SFC Use Cases . . . . . . . . . . . . . . .  20
   8.  Requirements from Traffic Steering Use Cases  . . . . . . . .  22
   9.  Requirements from MPLS TE Networks Use Cases  . . . . . . . .  22
   10. Requirements from MPLS LDP Networks Use Cases . . . . . . . .  24
   11. Requirements from Mobile Backhaul Ues Cases . . . . . . . . .  25
   12. Requirements from Large Data Flows are  . . . . . . . . . . .  27
   13. Large Data Collection Systems . . . . . . . . . . . . . . . .  28
   14. CDNI  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  30
   15. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  31
   16. Security Considerations . . . . . . . . . . . . . . . . . . .  31
   17. References  . . . . . . . . . . . . . . . . . . . . . . . . .  31
     17.1.  Normative References . . . . . . . . . . . . . . . . . .  31
     17.2.  Informative References . . . . . . . . . . . . . . . . .  31
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  34

1.  Introduction

   The Architecture for the Interface to the Routing System
   [I-D.ietf-i2rs-architecture] allows for a mechanism where the
   distributed control plane can be augmented by an outside control
   plane through an open, accessible interface.  This document
   summarizes the use case requirements for theI2RS client-I2RS Agent
   exchange found in the following documents:

   o  Protocol Independent described in [I-D.white-i2rs-use-case]

   o  BGP described in [I-D.keyupate-i2rs-bgp-usecases]

   o  IGP protocols as described in [draft-ietf-wu-i2rs-igp-usecases]





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   o  Control of Forwarding Path by Central Control Network Element
      (CCNE) [I-D.ji-i2rs-usecases-ccne-service]

   o  Virtual Connections and Virtual Networks described in
      [I-D.hares-i2rs-use-case-vn-vc]

   o  Topology use cases [I-D.amante-i2rs-topology-use-cases]

   o  Topology requirements [I-D.medved-i2rs-topology-requirements]

   o  Service chaining described in [I-D.bitar-i2rs-service-chaining]

   o  Traffic Steering described in [I-D.chen-i2rs-ts-use-case]

   o  MPLS TE Networks described in [I-D.huang-i2rs-mpls-te-usecases]

   o  MPLS LDP Networks described in [I-D.chen-i2rs-mpls-ldp-usecases]

   o  Mobile BackHaul Use cases described in
      [I-D.zhang-i2rs-mbb-usecases]

   o  Large Flows use case described in
      [I-D.krishnan-i2rs-large-flow-use-case]

   o  Large Data Collection Systems Use cases described in
      [I-D.swhyte-i2rs-data-collection-system]

   o  CDNI requesting routing
      [I-D.shin-i2rs-usecases-cdni-request-routing]

   Each group of use cases is presented in its own document.  Each use
   case is labeled with an identifier TTT-REQ-nn where TTT represents
   the type of use case.  The abbreviations for TTT are:

   o  PI - Protocol Independent

   o  BGP - BGP

   o  IGP - IGP protocols

   o  CCNE - CCNE control of forwarding path

   o  VCoD - Virtual Connections on Demand

   o  VNoD - Virtual Networks on Demand

   o  Topo - Topology Information




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   o  VT-TMD - Virtual Topology: Topology Data Model

   o  VT-TDM-IP - Virtual Topology: Topology Data Mode for IP/MPLS

   o  SFC - Service Chaining requirements

   o  TS - Traffic Steering

   o  MPLS-LDP - MLPS Topologies supported by LDP

   o  MPLS-TE - MPLS-TE topologies

   o  MBH - Mobile Back-Haul

   o  L-Flow - Large Flows

   o  L-Data - Large Data Collection

   o  CDNI - CDNI networks

   Each use case is also augmented with a notation signifying whether it
   is in or out of scope with regard to the current I2RS charter:

   o  IC: In charter

   o  OC: Out of charter

   o  NA: not applicable to I2RS protocol, agent, client or models.
      Usually related to specific client-side app requirements.

   o  ??: indicates this item needs additional classification aid from
      the WG.

   In some cases a specific draft may be out of charter, but
   (sub)components of it's requirement set may be in charter.  In
   charter.  As such, (IC|OC|NA) designations may appear at the draft
   level, at the requirement level, or at the sub requirement level.  In
   instances where designations do not appear at more specific level,
   the designation at the parent level should be considered to be
   inherited.

2.  Protocol Independent Use Case Requirements

   This is a summary of the I2RS requirements found in the Protocol
   Independent Use Cases described in: [I-D.white-i2rs-use-case] (IC):

   o  PI-REQ01 (IC): The ability to monitor the available routes
      installed in the RIB of each forwarding device, including near



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      real time notification of route installation and removal.  This
      information must include the destination prefix (NLRI), a table
      identifier (if the forwarding device has multiple forwarding
      instances), the metric of the installed route, and an identifier
      indicating the installing process.

   o  PI-REQ02 (IC): The ability to install source and destination based
      routes in the local RIB of each forwarding device.  This must
      include the ability to supply the destination prefix (NLRI), the
      source prefix (NLRI), a table identifier (if the forwarding device
      has multiple forwarding instances), a route preference, a route
      metric, a next hop, an outbound interface, and a route process
      identifier.

   o  PI-REQ03 (IC): The ability to install a route to a null
      destination, effectively filtering traffic to this destination.

   o  PI-REQ04(??): The ability to interact with various policies
      configured on the forwarding devices, in order to inform the
      policies implemented by the dynamic routing processes.  This
      interaction should be through existing configuration mechanisms,
      such as NETCONF, and should be recorded in the configuration of
      the local device so operators are aware of the full policy
      implemented in the network from the running configuration.

   o  PI-REQ05 (OC): The ability to interact with traffic flow and other
      network traffic level measurement protocols and systems, in order
      to determine path performance, top talkers, and other information
      required to make an informed path decision based on locally
      configured policy.

   o  PI-REQ06 (IC): The ability to install destination based routes in
      the local RIB of each forwarding device.  This must include the
      ability to supply the destination prefix (NLRI), a table
      identifier (if the forwarding device has multiple forwarding
      instances), a route preference, a route metric, a next hop, an
      outbound interface, and a route process identifier.

   o  PI-REQ07 (IC): The ability to read the local RIB of each
      forwarding device, including the destination prefix (NLRI), a
      table identifier (if the forwarding device has multiple forwarding
      instances), the metric of each installed route, a route
      preference, and an identifier indicating the installing process.

   o  PI-REQ08 (IC): The ability to read the tables of other local
      protocol processes running on the device.  This reading action
      should be supported through an import/export interface which can
      present the information in a consistent manner across all protocol



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      implementations, rather than using a protocol specific model for
      each type of available process.

   o  PI-REQ09 (OC for some protocols): The ability to inject
      information directly into the local tables of other protocol
      processes running on the forwarding device.  This injection should
      be supported through an import/export interface which can inject
      routing information in a consistent manner across all protocol
      implementations, rather than using a protocol specific model for
      each type of available process.

   o  PI-REQ10 (OC): The ability to interact with policies and
      configurations on the forwarding devices using time based
      processing, either through timed auto-rollback or some other
      mechanism.  This interaction should be through existing
      configuration mechanisms, such as NETCONF, and should be recorded
      in the configuration of the local device so operators are aware of
      the full policy implemented in the network from the running
      configuration.

   o  PI-REQ-11 (IC) The ability to update the Local RIB with varying
      levels of checks on the route.  These checks can be simply minimal
      reception checks (TLVs align corrrectly), all non-referential
      checks (do not do leafref, MUST, instance identifiers), do
      referential checks.

3.  BGP Use Case Requirements

   This is a summary of the requirements listed in
   [I-D.keyupate-i2rs-bgp-usecases] are (IC):

   o  BGP-REQ01 (IC): I2RS client/agent exchange SHOULD support the
      read, write and quick notification of status of the BGP peer
      operational state on each router within a given Autonomous System
      (AS).  This operational status includes the quick notification of
      protocol events that proceed a destructive tear-down of BGP
      session

   o  BGP-REQ02 (IC): I2RS client SHOULD be able to push BGP routes with
      custom cost communities to specific I2RS agents on BGP routers for
      insertion in specific BGP Peer(s) to aid Traffic engineering of
      data paths.  These routes SHOULD be tracked by the I2RS Agent as
      specific BGP routes with customer cost communities.  These routes
      (will/will not) installed via the RIB-Info.

   o  BGP-REQ03 (IC): I2RS client SHOULD be able to track via read/
      notifications all Traffic engineering changes applied via I2RS
      agents to BGP route processes in all routers in a network.



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   o  BGP-REQ04 (IC): I2RS Agents SHOULD support identification of
      routers as BGP ASBRs, PE routers, and IBGP routers.

   o  BGP-REQ05 (IC): I2RS client-agent SHOULD support writing traffic
      flow specifications to I2RS Agents that will install them in
      associated BGP ASBRs and the PE routers.

   o  BGP-REQ06 (IC): I2RS Client SHOULD be able to track flow
      specifications installed within a IBGP Cloud within an AS via
      reads of BGP Flow Specification information in I2RS Agent, or via
      notifications from I2RS agent

   o  BGP-REQ07 (IC): I2RS client-agent exchange SHOULD support the I2RS
      client being able to prioritize and control BGP's announcement of
      flow specifications after status information reading BGP ASBR and
      PE router's capacity.  BGP ASBRs and PE routers functions within a
      router MAY forward traffic flow specifications received from EBGP
      speakers to I2RS agents, so the I2RS Agent SHOULD be able to send
      these flow specifications from EBGP sources to a client in
      response to a read or notification.

   o  BGP-REQ08 (IC): I2RS Client SHOULD be able to read BGP route
      filter information from I2RS Agents associated with legacy BGP
      routers, and write filter information via the I2RS agent to be
      installed in BGP RR.  The I2RS Agent SHOULD be able to install
      these routes in the BGP RR, and engage a BGP protocol action to
      push these routers to ASBR and PE routers.

   o  BGP-REQ09 (IC): I2RS client(s) SHOULD be able to request the I2RS
      agent to read BGP routes with all BGP parameters that influence
      BGP best path decision, and write appropriate changes to the BGP
      Routes to BGP and to the RIB-Info in order to manipulate BGP
      routes

   o  BGP-REQ10 (IC): I2RS client SHOULD be able instruct the I2RS
      agent(s) to notify the I2RS client when the BGP processes on an
      associated routing system observe a route change to a specific set
      of IP Prefixes and associated prefixes.  Route changes include: 1)
      prefixes being announced or withdrawn, 2) prefixes being
      suppressed due to flap damping, or 3) prefixes using an alternate
      best-path for a given IP Prefix.  The I2RS agent should be able to
      notify the client via publish or subscribe mechanism.

   o  BGP-REQ11 (IC): I2RS client SHOULD be able to read BGP route
      information from BGP routers on routes in received but rejected
      from ADJ-RIB-IN due to policy, on routes installed in ADJ-RIB-IN,
      but not selected as best path, and on route not sent to IBGP peers
      (due to non-selection).



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   o  BGP-REQ12 (IC): I2RS client SHOULD be able to request the I2RS
      agent to read installed BGP Policies.

   o  BGP-REQ13 (IC): I2RS client SHOULD be able to instruct the I2RS
      Agent to write BGP Policies into the running BGP protocols and
      into the BGP configurations.

   o  BGP-REQ14 (IC): I2RS client-agent SHOULD be able to read BGP
      statistics associated with Peer, and to receive notifications when
      certain statistics have exceeded limits.  An example of one of
      these protocol statistics is the max-prefix limit.

   o  BGP-REQ15 (IC): The I2RS client via the I2RS agent MUST have the
      ability to read the loc-RIB-In BGP table that gets all the routes
      that the CE has provided to a PE router.

   o  BGP-REQ16 (IC): The I2RS client via the I2RS agent MUST have the
      ability to install destination based routes in the local RIB of
      the PE devices.  This must include the ability to supply the
      destination prefix (NLRI), a table identifier, a route preference,
      a route metric, a next-hop tunnel through which traffic would be
      carried

   o  BGP-REQ17 (IC): The I2RS client via the I2RS agent SHOULD have the
      the ability to read the loc-RIB-in BGP table to discover
      overlapping routes, and determine which may be safely marked for
      removal.

   o  BGP-REQ18 (IC): The I2RS client via the I2RS Agent SHOULD have the
      ability to modify filtering rules and initiate a re-computation of
      the local BGP table through those policies to cause specific
      routes to be marked for removal at the outbound eBGP edge.

4.  IGP Use Cases

   This is a summary of the requirements listed in (ietf-draft-wu-ir2s-
   igp-usecases-00.txt) (OC):

   o  IGP-REQ-01 (OC): I2RS Client/Agent SHOULD Be able to read/write
      the the unique IGP identification for router within an AS (router-
      id, system-id, or others).  I2RS agents may notify the I2RS client
      of the detection of another router with the same unique ID.

   o  IGP-REQ-02 (OC): I2RS Client SHOULD BE able to aid in IGP table
      reduction by actively monitoring IGP tables and by allowing
      changes to the IGP configuration in order to partition the IGPS
      and place ABRs and ASBRs.  The I2RS Client/Agent exchange must
      allow for a rapid cycle of querying of IGP topology information



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      and downloading of a new protocol configuration or updating of IGP
      nexthops in RIBs and FIBs to rapidly switch to new temporary IGP
      topologies.  These alternate topologies may be calculated by a
      application attached to the i2rs client and updated to the i2rs
      agent, or determined at the i2rs agent.

   o  IGP-REQ-03 (OC): I2RS protocol and models should support Loop-Free
      Alternative (LFAs) [RFC5286] deployments in in pure IP and MPLS/
      LDP networks to provide single-point-failure protection for
      unicast traffic.  This includes the configuration, monitoring of
      LFA changes, and letting off-line pre-computed paths for LFA
      backup of all links and prefixes in the network and calculating
      the protection coverage and recognizing optimization to be
      downloaded to appropriate devices via the I2RS interface (Client-
      Agent).  Again, it is important to have deployment of changes
      followed by real-time feedback.

   o  IGP-REQ-04 (OC): The I2RS programmatic interface SHOULD allow the
      balancing of both ECMP traffic flows and end-to-end traffic flows
      in the IGP.  The I2RS SHOULD support monitoring of the dynamic
      traffic flow in the network, and the query of the maximum capacity
      of the network.  This include the I2RS client's transmission to
      the I2RS agent of updated configuration after an off-line
      optimization to either spread traffic (across ECMP pathways) or
      aggregation of traffic onto a single path so the rest of the
      devices may power off saving power (and money.

   o  IGP-REQ-05 (OC): The I2RS interface (protocol and data models)
      SHOULD use the subscription mechanism to filter the topology
      changes to interested events and use the publish mechanism to
      control the pace these events are notified.  This filtering should
      protect the I2RS Client or even applications who depend on
      topology data from being drowned by massive original events or
      duplicate events from different sources

   o  IGP-REQ-06 (OC): Since IGP protocol is essential to the whole
      network, the I2RS Clients SHOULD monitor about the protocol's
      running status before forwarding is impacted.  Performance data
      can be collected through collecting static configuration and
      observing dynamic status.  Static data includes the number of
      instances, interfaces, nodes in the network and etc.  Dynamic data
      includes adjacency status, the number of entries in link-state
      database and in the routing table, the calculation status, the
      overload status, the graceful switch-over status, and others

   o  IGP-REQ-07 (OC): The I2RS interface (protocol and IMs) should
      support a mechanism where the I2RS Clients can subscribe to the
      I2RS Agent's notification of critical node IGP events.  For



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      example, link-state database or routing table is under the status
      of overflow or the overflow status is released, the calculation
      continues for a long time, the system is under graceful reboot.

   o  IGP-REQ-08 (OC): The I2RS interface (protocol and IMs) should
      support the reporting of IGP statistic such as dropped packet
      statistics.  These statistics will aid detection of network
      failures or secruity attacks.

5.  CCNE Use Cases

   The use cases in I2RS Use Cases for Control of the Forwarding Path by
   a Central Control Network Element (CCNE)
   [I-D.ji-i2rs-usecases-ccne-service] indicate the following
   requirements for I2RS (OC):

   o  CCNE-REQ-01 (IC): I2RS interface should support I2RS client
      running on a CCNE to be able to pull information from both the BGP
      RR and the PCE.  This information can include: BGP topology
      information, BGP routes, BGP statistics, BGP Peer topologies, PCE
      topology information, and PCE state information.  The I2RS
      Client's request for reading of the RR and PCE topology
      information needs to have timely and rapid response from the I2RS
      Agent.

   o  CCNE-REQ-02 (IC for some constraints): I2RS client should be able
      to set resource constraints at the I2RS Agent, and receive status
      information on the setting of resource constraints.

   o  CCNE-REQ-03 (IC for some constraints): I2RS interface should be
      able to set service goal value to CCNE.

   o  CCNE-REQ-04 (OC): I2RS client should be able support information
      models that allow re-optimization traffic model at at CCNE .

   o  CCNE-REQ-05 (IC): I2RS client should be able to receive
      notification at the CCNE, and be able to send status to the I2RS
      agent.

   o  CCNE-REQ-06 (NA): I2RS client should work in parallel with
      traditional network management or OAM protocols sent to the
      general NE.

   o  CCNE-REQ-07 (NA): I2RS clients should be able to to be light
      weight enough to be able to support running on a variety of
      devices (routers, centralized servers, or devices doing both).





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6.  Topology Related Use Cases

   This section describes Topology or Virtual Topology related
   requirements the I2RS interface (protocol and information model (IM)
   included in the following types of use cases:

   o  Virtual Connections on Demand: VCoD-REQ

   o  Virtual Networks on Demand: VNoD-REQ

   o  Virtual Topology Information Topo-REQ

   o  Virtual Topology Data Model: VT-TDM-REQ

   o  Virtual Topology IP Data Model: VT-TDMIP-REQ

   o  Virtual Topology Network Element: VT-NE-REQ (TMF-GEN-1)

6.1.  Virtual Connection Use Case Requirements

   o  VCoD-REQ01 (OC): I2RS Agents SHOULD provide the ability to read
      the virtual network topology database for the technology
      supported.  For optical, these are the optical connections and
      what node they connect to, and the topologies created.  For MPLS,
      this is virtual circuit available, what nodes they connect to, and
      the network topologies created.  For IP technologies, this could
      include the GRE tunnels, what interface it connects to, and the
      topologies created.  For Ethernet circuits this should involve
      circuit type (e.g, point-to-point (p2p) or point-to-multipoint
      (p2mp)) and what nodes it can reach, and the topologies created.

   o  VCoD-REQ02 (OC): I2RS Agent SHOULD provide the ability to
      influence the configuration of a virtual circuit in a node.

   o  VCoD-REQ03 (OC): I2RS Agent SHOULD provide monitor and provide
      statistics on the virtual connection to the I2RS client via a Read
      request or status Notification.  The I2RS client can then
      determine if the connection falls below a quality level the
      application has requested.  If the I2RS client does determine the
      circuit is below the required quality, it could create another
      circuit.  The I2RS may choose to create the second virtual
      circuit, transfer flows, and then break the first circuit.

6.2.  Virtual Network Use Case Requirements

   The requirements for the Virtual Networks on Demand (VCoD) are:





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   o  VT-VN-REQ01 (IC): I2RS Agents SHOULD provide the ability to read
      the virtual network topology database for the technology supported
      to determine nodes and connections.  For optical, these are the
      optical connections and what node they connect to, and the
      topologies created.  For MPLS, this is virtual circuit available,
      what nodes they connect to, and the network topologies created.
      For IP technologies, this could include the GRE tunnels, what
      interface it connects to, and the topologies created.  For
      Ethernet circuits this should involve circuit type (e.g, point-to-
      point (p2p) or point-to-multipoint (p2mp)) and what nodes it can
      reach, and the topologies created.

   o  VNoD-REQ02 (IC): I2RS Agent SHOULD provide the ability to
      influence the configuration of a virtual circuit in a node.

   o  VNoD-REQ03 (IC): I2RS Agent SHOULD provide monitor and provide
      statistics on the virtual connection to the I2RS client via a Read
      request or status Notification.  The I2RS client can then
      determine if the connection falls below a quality level the
      application has requested.  If the I2RS client does determine the
      circuit is below the required quality, it could create another
      circuit.  The I2RS may choose to create the second virtual
      circuit, transfer flows, and then break the first circuit.

   o  VNoD-REQ04 (IC): I2RS Agent SHOULD provide the ability to
      influence the configuration of a virtual network in a node.

   o  VNoD-REQ05 (OC): I2RS Agent SHOULD provide the ability to report
      statistics on the network nodes and end-to-end traffic flows via
      read of status data or via notifications of status.

   o  VNoD-REQ06 (IC): The I2RS protocol and RIB Informational Model
      (IM) must support logical tunnels of type MPLS as well as IP, GRE,
      VxLAN and GRE.  Large Carrier networks utilize MPLS in a variety
      of forms (LDP, static MPLS TE, or dynamic TE LSPS created by RSVP-
      TE or CR-LDP).

   o  VNoD-REQ07 (IC): I2RS SHOULD support Informational Models and
      features to allow MPLS technologies to create Hub-spoke topology
      and service routing in networks in Carriers, Enterprise, and Data
      Centers.

   o  VNoD-REQ08 (IC): I2RS protocols, Information Models, and Data
      Models must be able to support Carriers using these MPLS
      technologies to support networks for Mobile BackHaul, on-demand
      MPLS overlays, and on-demand video conferencing networkings.





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6.3.  Topology Use Case

   The requirements in [I-D.amante-i2rs-topology-use-cases] topology use
   cases focus around the architecture of topology manager,
   orchestration manager, and policy in the figure below (IC):

                                            +---------------+
                              +----------------+ |
                              |  Applications  |-+
                              +----------------+
                                      ^   Websockets, ReST, XMPP...
             +------------------------+-------------------------+
             |                        |                         |
       +------------+     +------------------------+     +-------------+
       |   Policy   |<----|    Topology Manager    |---->|Orchestration|
       |   Manager  |     | +--------------------+ |     |   Manager   |
       +------------+     | |Topology Information| |     +-------------+
                          | |       Model        | |
                          | +--------------------+ |
                          +------------------------+
                                    ^ ^ ^
         Websockets, ReST, XMPP     # | *  Websockets, ReST, XMPP
              ####################### | ************************
              #                       |                        *
       +------------+                 |                  +------------+
       | Statistics |                 |                  | Inventory  |
       | Collection |                 |                  | Collection |
       +------------+                 |                  +------------+
             ^                        | I2RS, NETCONF, SNMP,   ^
             |                        | TL1 ...                |
             +------------------------+------------------------+
             |                        |                        |
     +---------------+        +---------------+        +---------------+
     |Network Element|        |Network Element|        |Network Element|
     | +-----------+ |        | +-----------+ |        | +-----------+ |
     | |Information| |<-LLDP->| |Information| |<-LMP-->| |Information| |
     | |   Model   | |        | |   Model   | |        | |   Model   | |
     | +-----------+ |        | +-----------+ |        | +-----------+ |
     +---------------+        +---------------+        +---------------+

   o  Topo-REQ-01 (IC): The Topology Manager Should be able to collect
      topological information via the I2RS Client-Exchange exchange from
      a variety of sources in a normalized topological model.  These
      sources can be:

      *  Live Layer IGP IGPs with information about the active topology
         such as the LSDB database or IGP updates,




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      *  The I2RS must enable the inventory system information to query
         for information about network components which are not not
         visible to active L3.  These systems can be active or simply
         invisible to the L3.  Examples of this are L2 Ethernet switches
         or ROADMS.

      *  Statistic Collection systems that provide traffic information,
         such as traffic demands or link utilizations.

      (from section 3.2)

   o  Topo-REQ-02 (OC): Topology information is provided from Clients to
      high-layer applications via a northbound interface (such as ReST,
      Websockts, or XMPP.

   o  Topo-REQ-03 (IC): Topology Manager should be able to collect and
      keep current topology information for multiple layers of the
      network: Transport, Ethernet and IP/MPLS, as well as information
      for multiple Layer 3 IGP areas and multiple Autonomous Systems
      (ASes).  This information must contain cross-layer unerlying
      Shared Risk Link Groups (SRLG) within transport or Ethernet
      layers. (from section 3.2)

   o  Topo-REQ-04 (OC): Topology manager be able to use I2RS Client-
      Agent protocol to to collect dynamic inventory information from
      network elements.  An example of these protocols are the Link
      Layer discovery protocols (LLDP, LMP, etc.) which automatically
      identify remote nodes and ports. (from section 3.2)

   o  Topo-REQ-05 (IC):I2RS Should enable the Policy manager to query
      and store the following types of policies:

      *  Policies that contain Logical identifier Numbering in order to
         correlate IP Prefixes to

         +  link based on link type (P-P, P-PE, or PE-CE),

         +  IGP Area

         +  L2 VLAN assignments

      *  Routing Configuration policies that correlate:

         +  OSPF area/ISIS Net-ID to Node (type)

         +  BGP node related policies (aggregation routes at node, max-
            prefix (per node), or AFI/SAFI per node




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         +  Security policies - with ACLs or rate-limits

         +  Network Component access policies (for management

      (from section 3.3)

   o  Topo-REQ-06 (OC): I2RS should enable a orchestration manager
      attached to an I2RS client to communicate with I2RS agents into
      order to stitch together End-to-end services for network bandwidth
      optimization, load balancing, and Class-of-Service with point
      services (Firewall or NAT) within the end-to-end service).  The
      orchestration manager should also be able to immediately schedule
      any of these resources via the I2RS-Client I2RS agent exchange.
      (from section 3.4)

   o  Topp-REQ-07 (OC): The I2RS exchange should enable a statistics
      collector to collect statistics from the routing function of the
      network nodes and archive and aggregate the statistics into a
      statistics warehouse.  Statistics must be given and stored in an
      normalized form.  Metadata must be stored with the statistics.
      (from section 4.1.1.2) (Editor: there is some suggestion of
      periodic reports)

   o  Topo-REQ-08 (IC): I2RS Client-I2RS agent exchange must be provide
      enough interoperability that the Topology manager, Policy manager,
      and inventory systems can be available from different vendors

   o  Topo-REQ-09 (IC): TE tunnels must be able to be created by the
      exchange between the I2RS client and the I2RS agent. (from section
      4.1.1)

   o  Topo-Req-10 (NA): I2RS must provide a common and up-to-date
      normalized view of the topologies that that support security
      auditing, and IP/MPLS Provisioning (L2/L3) which includes:

      *  Identifying Service PE's in all markets/cities where the
         customer has identified they want service,

      *  Identifying one or more existing Servies PE's in each city with
         connectivity to the access network(s) ( e.g.: SONET/TDM) used
         to deliver the PE-CE tail circuits to the Service's PE),

      *  Obtain via query/notification the available capacity on
         Services PE in both the PE-CE access interface and its uplinks
         to terminate the tail circuit

      *  Providing the context in I2RS for an iterative query mechanism
         needed by I2RS client attached to the the Topology to narrow



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         down the scope of resources to the set of Services PEs with the
         appropriate uplink bandwidth and access circuit capability plus
         capacity to realize the requested VPN service.

      (from section 4.1.2)

   o  Topo-REQ-11 (NA): The VPN application attached to the I2RS client
      should be able to hand the I2RS Client a candidate list of Service
      PE's and associated access circuits to set up a Customer's VPN
      service into the network.  (from section 4.1.3) [Editor's note
      This request shares requirements with VCoD-REQ-01.]

   o  Topo-REQ-12 (NA): The Topology Manager associated with the I2RS
      client must be able to use the normalized view of the network to
      set up additional queries (or notification publications) to
      provide an accurate and comprehensive picture in order a) diagnose
      faults/failures, and b) augment the network with additional
      services, and c) provide network topology maps for different
      purposes.  (from section 4.1.3)

   o  Topo-REQ-13 (IC):The I2RS client-agent exchange and informational
      models should support a Virtual Network Topology (VNT) comprise of
      one or more LSPS and lower layer resources.  The VNT of MPLS must
      be able to link lower layer resources with the higher layer, and
      present a normalize form the the PCE as defined [RFC5623].

   o  Topo-REQ-14 (OC): The I2RS client-agent protocol and models should
      support the use of a PCE to compute MPLS-TE paths within an
      "domain" (IGP area), or across multiple "domains" (multi-area AS,
      multiple ASes") as specified in [RFC4655].  This means the PCE
      Informational model should support:

      *  enhanced computation in the single IGP domain

      *  cross-AS path computation based on the multiple entrance of
         exit points from an AS,

      *  linking multiple PEs in multiple domains together, and

      *  synchronization of TED associated with the PCE to the topology
         manager (via I2RS client/messages), and

      *  sending read/writes to the head-end-nodes

      (section 4.3)

   o  Topo-REQ-15 (OC): the I2RS protocol and Information models should
      support the ALTO ([RFC5693]) generation of abstract network



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      topology models and the APIs it support over web-service API.  The
      ALTO abstract network topology comes in two forms: Network Map
      (based prefix-to PID mapping), and Cost map.  The ALTO map is
      automatically generated from BGP and IGP data which the ALTO
      server queries from the network and makes available to
      applications via web-service API. (from section 4.4)

6.4.  Virtual Topology Data Model

   The [I-D.medved-i2rs-topology-requirements] specifies the following
   Topology Data Model requirements (IC):

      VT-TDM-REQ1 (IC): The topology data model MAY be able to describe
      topology and characteristics of the following layers:

      *  Optical DWDM (optional) (OC),

      *  Optical OTN (optional) (OC),

      *  L2 (Aggregated links, L2 topologies) (IC),

      *  IP/MPLS (IC),

      *  VPNs (IC), and

      *  Services (such as cloud services, or CDNs).

      VT-TDM-REQ2 (IC): The topology data model MUST support multiple
      Autonomous System deployments.

      VT-TDM-REQ3 (IC): The I2RS topology data model must support
      include topology information from multiple Administrative Domains
      or multiple elements into a single common format.

      VT-TDM-REQ4 (IC): The I2RS topology data model MUST be able to
      convey enough information so that an I2RS client can correlate
      topologies in different layers and multiple Autonomous Systems.

      VT-TDM-REQ5 (NA): The topology data model MUST support multi-layer
      group of elements as a means of coalescing different SFF Nodes and
      links into a network layers from various layers.  For example,
      links with IPv4 addresses might represent Layer 3 of the network
      topology while links with Ethernet MAC addresses might represent
      Layer 2.

      VT-TDM-REQ6 (IC): The topology model should allow association
      between components of different layers.  For example, Layer 2 port




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      may have several IPv4/IPv6 interfaces.  The Layer-2 port and the
      IPv4/IPv6 interfaces would have an association.

      VT-TDM-REQ7 (NA): The topology model MUST represent both inactive
      and active topologies in the topology Data base.  Inactive
      topologies may include new line cards, ports in down state, etc.

      VT-TMF-DM-REQ8 (NA): The topology data model MUST be hierarchical
      and MUST support summarization of sub-topologies.  Topology
      summarization and creation of abstract topologies can be provided
      by either by the application associated with the I2RS client, or
      by the I2RS Agent prior to transmission to the I2RS client.

      VT-TDM-REQ9 (IC): The topology data model MUST be able to describe
      abstract topologies.  Abstract topologies can contain real and
      abstract nodes and real and abstract links.  An abstract topology
      MAY be used by a provider to describe characteristics of a transit
      network (bandwidth, delay, protection, etc.)

      VT-TDM-REQ10 (OC): The topology data model MUST support dynamic
      data, such as link and node utilizations (perhaps as optional
      attributes).

      VT-TDM-REQ11a (??): The topology data model MUST allow I2RS
      client-agent to be able to identify and query for the path between
      two nodes.

      VT-TDM-REQ11b (OC): The topology data model should support the
      I2RS Client requesting the I2RS Agent to trace the path at all
      network layers that participate in the delivery of packets between
      two nodes.  This trace MAY involve either an I2RS Agent
      information trace or the I2RS Agent requesting the routing
      function trace the path at multiple levels (L3/L2.5/L2/L1)

      VT-TDM-REQ12 (IC): The topology data model MUST support multiple
      BGP Autonomous Systems and multiple IGP areas.  Support for
      multiple administrative domains is for further study.

      VT-TDM-REQ13 (IC): The topology data model MUST be human-friendly,
      i.e. not SNMP MIBs, but something much more analogous to YANG
      models.

      VT-TDM-REQ14 (IC): The data model SHOULD support topology
      abstraction, allowing clients that consume topology information in
      a constrained manner.  For example, a client wishing to view only
      interfaces and nodes present in a sub-graph of the Layer 3
      topology should be able to specify an interest in this subset of




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      information rather than having to read out and parse through the
      entire set of links and nodes.

6.5.  Virtual Topology IP Data Model

   The [I-D.medved-i2rs-topology-requirements] specifies the following
   requirements for the Virtual Topology IP Data Model's IP/MPLS links
   and topologies (IC):

   o  VT-TDM-IP-REQ1 (IC): The I2RS topology data model for the IP/MPLS
      layer MUST support both link topology and prefixes,

   o  VT-TDM-IP-REQ2 (IC): The I2RS agent may import topology
      information from the routing processes, IGP process, BGP-LS
      information, or management processes.

   o  TM-DM-IP-REQ3 (IC): The I2RS SFC Data model must support links
      that are IP/MPLS with the following attributes:

      *  local and Remote anchor node IDs (Router ID, AS#, Area ID, MT
         topology),

      *  metrics,

      *  admin group,

      *  max bandwidth links

      *  unreserved/utilized bandwidth

      *  link-protection type

      *  MPLS protocol mask

      *  link prefix

      *  link characteristics (BW, Delay, error rate)

      *  Link Description, and

      *  Link-specific timers (Hello and Holddown).

6.6.  Virtual Topology Network Element

   The [I-D.medved-i2rs-topology-requirements] specifies the following
   requirements (IC):





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   o  VT-NE-01 (IC): Each network element should contain an inventory
      data base which should be a definitive source of information with
      respect to the physical HW and Logical, logically significant
      identifiers (E.g.  VLANs).  The I2RS client should be able to
      import data from this DB into the I2RS Node IM or SFC IM.

   o  VT-NE-02 (IC): The inventory DB of the network element should be
      augmented with the physical properties associated with the ports/
      interfaces that are directly connected to the device (BW, media
      type).  The I2RS client should be able to import data from this
      augmented DB into the I2RS Node IM or SFC IM.

   o  NE-3 (NA): The I2RS client may write information into the NE
      inventory data base via the Network-element Data Model that the
      network element may not be able to learn on its own.  This
      information may include the physical location (address), rack/bay
      information.

7.  Requirements from SFC Use Cases

   The SFC use case document in [I-D.bitar-i2rs-service-chaining]
   suggests that the following requirements (OC):

   SFC-Use-REQ01 (IC):Address

      has the following address requirements:

      *  IP address

      *  service-node tuple (service node IP address, Host system
         address)

      *  host-node tuple (hosting system IP-address, system internal
         identifier)

   SFC-Use-REQ02 (IC):Supported Service Types

      SHOULD include: NAT, IP Firewall, Load balancer, DPI, and others

   SFC-Use-REQ03 (IC):Virtual contexts

      SHOULD include:

      *  Maximum Number of virtual contexts supported

      *  Current number of virtual contexts in use

      *  Number of virtual contexts available



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      *  Supported Context (VRF)

   SFC-Use-REQ04 (IC): Customers currently on node


   SFC-Use-REQ05 (IC): Customer Support Table (per customer ID)

      *  Customer-id

      *  List of supported Virtual Contexts

   SFC-Use-REQ06 (OC): Service Resource table

      which includes:

      *  index: Comprised of service node, virtual context, service type

      *  service bandwidth capacity

      *  supported packet rate (packets/second)

      *  supported bandwidth (kps)

      *  IP Forwarding support: specified as routing-instance(s), RIBs,
         Address-families supported

      *  Maximum RIB-size (WG Note: problematic)

      *  Maximum Forward Data Base size (WG Note: problematic)

      *  Maximum Number of 64 bit statistics counters for policy
         accounting

      *  Maximum number of supported flows for services (WG Note:
         problematic)

   SFC-Use-REQ07 (IC): Virtual Network Topology (VNT)

      which includes:

      *  number of access points to which service topology applies

      *  topology of access points








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8.  Requirements from Traffic Steering Use Cases

   The requirements from the Traffic Steering use case described in
   [I-D.chen-i2rs-ts-use-case] are (OC):

   o  TS-REQ01 (IC): The I2RS Client-Agent must be able to collect the
      topology (especially the exit links) and the traffic load of each
      link;

   o  TS-REQ02 (IC): The I2RS Client-Agent must be able to read the
      local rib of each DC/Metro gateway and the policies deployed on
      each gateway;

   o  TS-REQ03 (IC): The I2RS Client-Agent must be able to add or delete
      or modify the relevant rib items and relevant polices to steer the
      traffic as expected; and adjust traffic placement.

   o  TS-REQ-04 (IC): The I2RS Client-Agent must have the ability to
      collect the LSP information either from the PCE or directly from
      network devices;

   o  TS-REQ-05 (OC): The I2RS Client-Agent must have the ability to
      collect the traffic matrix of the network, this is used to help
      the I2RS client to determine how to adjust the traffic placement;

   o  TS-REQ-06 (IC): The I2RS Client-Agent must have the ability to
      read the rib information and relevant policies of each network
      node;

   o  TS-REQ-07 (OC):collect the topology and segment information needed
      to help the I2RS client to compute the end-to-end path;

   o  TS-REQ-08 (OC):read rib (especially the segment routing rib)
      information;

   o  TS-REQ-09 (??): add/delete/modify the segment rib, this finally
      determines how the traffic is forwarded.

9.  Requirements from MPLS TE Networks Use Cases

   Theses are the requirements from the Traffic Steering use case
   described in [I-D.huang-i2rs-mpls-te-usecases] (OC):

   o  MPLS-TE-REQ-01 (OC): Network programming software managing the
      static CR-LSP devices may incorporate an I2RS Client along with a
      path calculation entity, a label management entity, and a
      bandwidth management entity.  The I2RS Client should be abl to




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      communicate the static configuration to the network nodes, and
      monitor the status of the CR-LSPs.

   o  MPLS-TE-REQ-02 (OC): The I2Client should be able to synchronously
      send the configuration for all of the network nodes from egress
      node to ingress node via the I2RS Agents attached to each node,
      and be able to delay the final ingress node configuration until
      all the I2RS AGents on all other nodes toward the egress have
      denoted a successful path set-up.

   o  MPLS-TE-REQ-03 (OC): MPLS TE defines abundant constraints such as
      explicit path, bandwidth, affinity, SRLG, priority, hop limit, and
      others.  The I2RS Client Agent exchange should be able to signal
      concurrent local path calculation could obtain an optimized result
      and allow more services to be held in a TE network.  The I2RS
      Agent should be able to trigger a global concurrent re-
      optimization at a specific time on multiple nodes by communicating
      with each node's I2RS agent.

   o  MPLS-TE-REQ-04 (NA): The I2RS client should be able to manually
      calculate a re-optimization of the the MPLS TE network and send
      the new constraints including the calculated path to each node via
      the I2RS agent with an indication to re-signal the TE LSPs with
      make-before-break method.

   o  MPLS-TE-REQ-05 (OC): With I2RS, the node's I2RS agent should be
      able to send to an I2RS client a status notification that not
      enough resources exist for a back up LSP and TE tunnel.  Upon
      receiving this notification the I2RS client should be able to
      trigger concurrent calculation for the failed path calculation of
      the backup LSP or TE tunnel and send the updated paths to I2RS
      agents with a command to re-signal the TE LSPS with make-before-
      break Method.

   o  MPLS-TE-REQ-06 (NA): With I2RS, upon receipt the failure
      notification from an I2RS Agent, the I2RS client would create a
      global concurrent optimization to handle the failure event.  This
      would occur by the I2RS client signalling the I2RS agents on all
      nodes to: a) trigger a new concurrent calculation of the backup
      LSP or TE tunnel via failed path calculation, and b) re-signal
      updates to the TE LSPs process with a make-before-break method.

   o  MPLS-TE-REQ-07 (NA): Upon receiving a signal an upgrade event
      signal (from operator), the I2RS client could calculate another
      path for the affected TE tunnels to deviate traffic away from the
      resource being upgraded, and then send the request to I2RS agents
      on the appropriate nodes to move the traffic.  After the upgrade
      completes, the I2RS client can simply remove I2RS configurations



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      causing the traffic to revert to the original path.  Or, the I2RS
      can re-optimize the TE tunnels for another pathways (E.g.  as a
      part of a sequence of upgrades).

   o  MPLS-TE-REQ-08 (OC): I2RS agents can notify I2RS Clients of
      impending or existing MPLS TE overload conditions that might cause
      TE LSP rejections.  This overload conditions include: due to CPU,
      memory, LSP label space, or LSP numbers.

   o  MPLS-TE-09 (IC): Automatic bandwidth adjustment applications can
      also be linked to the I2RS clients need to monitor the traffic on
      TE tunnels in order to provide traffic analysis.  The I2RS client
      should be able to read the TE Tunnel topology and the bandwidth
      analysis in order to automatically calculate a new path for the TE
      tunnel if it is needed.  The I2RS Client also needs to be able to
      the I2RS agents in the nodes to install the new TE Tunnels with
      the make-before-break option.

   o  MPLS-TE-REQ-10 (IC): With I2RS, the node failure or link failure
      can be part of the notification stream sent by an I2RS Agent to an
      I2RS Client on a centralized server gathering information.

   o  MPLS-TE-REQ-11 (IC): The I2RS client can notify the I2RS agents on
      specific nodes (or devices) to re-signal TE LSPs one by one if
      there is a resource dependency.

   o  MPLS-TE-REQ-12 (IC): The I2RS Client can gather the TE LSPs' state
      from I2RS Agents on all nodes in order to coordinate such handling
      of LSP resources.

   o  MPLS-TE-REQ-13 (OC): The I2RS Clients collecting information from
      I2RS Agents can be arranged in a hierarchy to provide scaling of
      collections.  An application hosting an I2RS client collecting
      information from I2RS Agents on nodes can have an I2RS Agent that
      reports combined information to a single location.

10.  Requirements from MPLS LDP Networks Use Cases

   These are the I2RS requirements for the MPLS LDP use case described
   in [I-D.chen-i2rs-mpls-ldp-usecases]:

   o  MPLS-LDP-REQ-01 (IC): The I2RS Client-agent exchange should allow
      the distribution of the configuration for PWE3, MPLS LDP and
      associated protocols to be distributed from a central location
      where the global PWE3 provisioning information could be stored.
      The I2RS Client-Agent exchange should also be able to push the
      configuration of the local LDP LSR ID and peer addresses to set up
      the targeted session to the pseudowire endpoints.



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   o  MPLS-LDP-REQ-02 (IC): When an the end-user wants to disable
      IPoMPLS (IP over MPLS) application on a L2VPN/PW Targeted LDP
      session, the I2RS Client-I2RS agent should be able to set type of
      application over the established LDP session.  In this way LDP
      speaker can only advertise to its peer the application data which
      the user is interested in.

   o  MPLS-LDP-REQ-03 (OC): The I2RS Agent notifications should allow an
      I2RS client to subscribe to a stream of state changes regarding
      the LDP sessions or LDP LSPs from the I2RS Agent.  Specifically it
      is important that LDP session is tract for sessions state coming
      up or going down.  The I2RS Client-I2RS Agent exchange should
      allow additional queries to the AGent to determine a) why the
      service is invalid, b) calculating whether an alternate path
      should be switched to, and c) determining how to switch to other
      links or nodes in order to recover from the link failure or node
      failure.

   o  MPLS-LDP-REQ04 (IC): The I2RS interface provides way to monitor
      and control the limited resources on these access devices.  The
      I2RS client should be able to instruct the I2RS agent in each of
      these devices to set the maximum number of LDP LSPs in each device
      prior to enabling LDP on the devices.  The I2RS client should also
      be able to enable a notification service on each device with a
      with a warning threshold.  Once the number of LDP LSPs reaches the
      threshold, the I2RS agent will send a notification message to the
      I2RS client.  Often the I2RS client will be associated a network
      management agent that can determine what next steps need to be
      done based on policy or operator input.

11.  Requirements from Mobile Backhaul Ues Cases

   Mobile BackHaul Use cases described in [draft-ietf-zhang-mbb-
   usecases-01] are:

   o  MBH-REQ-01 (OC): The I2RS client-agent communication can
      distribute position-critical changes to IGP nodes using this
      global knowledge to quicken changes to support traffic during
      failures or traffic overloads.  To enable this feature, the I2RS
      Clients-Agent communication needs to pass information on which IGP
      process or Level or Area the given node and links belong to.

   o  MBH-REQ-02 (OC): I2RS must allow operators to use of I2RS clients
      to distribute time-critical changes in configuration to I2RS
      agents associated with each routing node.  This feature will
      simplify and automate configuration and monitoring of a mobile
      backhaul network to allow it to readily adapt to changing network
      sizes (and scales) and radio applications.



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   o  MBB-REQ-03 (OC): I2RS Clients-Agent communication needs to pass
      information on:

      *  T-LDP configurations and status;

      *  BGP peer configurations, peer topologies and status;

      *  BGP-based LSP topologies and status;

      *  Reset VPN topologies, and per node configurations;

   o  MBB-REQ04 (IC): Route policy enforcement in mobile backhaul
      networks needs to be more dynamic and flexible than the current
      methods take hours (or even days) to configure route policy across
      a network.  The I2RS interface must provide a programmatic way to
      configure (both policy and device) and monitor thousands of
      devices individually whose configuration is based on the devices
      role (such as ASRSs in one AS, ASBRs between ASs and other
      service-touch nodes).

   o  MBB-REQ-05 (NA): I2RS clients should be able to contact I2RS
      agents on nodes to query role-based information from the network
      status.  After collecting the status, the I2RS client can develop
      the BGP policies based on role information and push the BGP
      policies to the I2RS agents that would load the alternate policies
      into the network device.  The I2RS Agents loading the alternate
      policies could then send status back to the I2RS Client.

   o  MBH-REQ06 (??): I2RS clients can provide centralized control of
      many network devices via the I2RS Client-Agent communication.  The
      I2RS programmatic interface can automate the collection and
      analysis of each device's capability so that the centralized I2RS
      client could calculate the optimal LSP path and distribute the
      configuration to individual devices.  Automation of the collection
      of device capability should be available as query, notification,
      or a published stream.

   o  MBH-REQ07 (NA): While the I2RS RIB Information Model
      [[I-D.ietf-i2rs-rib-info-model]] provides for routes with tunnels
      or MPLS LSP, the features defined in this model are not sufficient
      to configure both types of LSPs needed for the VPN technology in
      mobile backhaul networks.  Additional I2RS Informational models
      need to be created to support these features.

   o  MBH-REQ08 (NA): The hierarchical protection architecture in mobile
      backhaul network offer high network reliability and more
      flexibility to meet the various needs of the tunnels and services.
      The I2RS interface in this use case is needed to automate the



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      configuration and monitoring so that tunnel protection and service
      protection interwork in a flexible and reliable manner.

   o  MBB-REQ09 (OC): The I2RS architecture (client-agent) should allow
      the two features for network monitoring naturally in its basic
      modes:

      *  allow a combination of multi-layer network monitor tools with
         exact detection parameters to be configured on the network
         device

      *  Facilitate the reporting the detection result as notification
         or publication stream

      It is important the result of these features allow the outages and
      traffic congestion or discards to be detected real-time with I2RS
      Client(s) in each node, and the detection result will be reported
      to the I2RS agents to get the exact status of the network.

12.  Requirements from Large Data Flows are

   Each of these requirements has been given an an ID number of L-Flow-
   nn for ease of reference.

   The requirements from the Large Data Flows use case described in
   [I-D.krishnan-i2rs-large-flow-use-case] are (IC):

      L-Flow-REQ-01 (IC): For redirecting large flows to a specific
      component, a PBR entry should be programmable for the flow with
      its nexthop that identifies the specific LAG or ECMP component.

      L-Flow-REQ-02 (IC): For adjusting the weights used to distribute
      traffic across components of the LAG or ECMP, I2RS should provide
      a programmable mechanism should be provided that identifies ECMP
      entries and is able to associate weights that can be programmed
      for each of the components.  To do this in a scalable fashion, it
      would be useful to have the notion of an ECMP nexthop that is used
      by multiple routes

      L-Flow-REQ-03 (IC): The I2RS interface (protocol/IMs) should allow
      for a globally optimal path is programmed in the IP network using
      hop-by-hop PBR rules.  These PBR rules may include:

      *  Being able to adjust the weights of the ECMP table for
         different nexthops should be adjusted to factor the large flows

      *  Being able to address an ECMP group, so that all routes sharing
         an ECMP group are addressed together.



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      *  the ability to program PBR entries at the edge LSR, and

      *  the ability to program new LSPs in the network.

      L-Flow-REQ-04 (OC): The I2RS protocol should be able to invoke the
      link aggregation IEEE 802.1AX Marker Protocol via the I2RS
      protocol.  This is useful during a period of rebalancing occurs
      before flows are moved.

      L-Flow-REQ-05 (IC): The I2rs protocol should allow Quality of
      Service (QoS) actions such as rate-limiting, re-marking, or
      discarding can be performed on the flows based on configured
      policies and nexthop redirection actions to be programmed, and to
      be programmed independently of of each other.

      L-Flow-REQ-06 (IC): Once a large flow has been detected, I2RS must
      be used to modify the forwarding tables in the router to:

      *  In the case of large flow load balancing, be able to
         redirecting the large flow to a particular member with the LAG
         or ECMP group and readjusting the weights of the other members
         to account for the large flow

      *  In the case of DDoS mitigation, the action involves rate
         limiting, remarking or potentially discarding the large flow in
         question.

13.  Large Data Collection Systems

   The requirements from the Large Data Collection Systems Use cases
   described in [draft-swhyte-i2rs-data-collection-system] are (OC) and
   (IC):

      L-Data-REQ-01 (OC): I2rs must be able to collect large data set
      from the network with high frequency and resolution with minimal
      impact to the device's CPU and memory.

      L-Data-REQ-02 (IC): I2RS must be able to use a database model
      where the data on the network node must be able to be described in
      the I2RS exchange as the data plus the structure of the data.  The
      I2RS management system consumes and understand the data only after
      it consumes and understand the database model or has been trained
      by vendor published model

      L-Data-REQ-03 (IC): I2RS should use a pub-sub model which allows
      scaling plus push or pull of data.





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      L-Data-REQ-04 (IC): I2RS should support capability negotiation to
      inform a subscriber of the options for publication of data.  The
      options include transport, security, and error handling.

      L-Data-REQ-05 (IC): The I2RS data tansfer should be format
      agnostic.  This means the publisher and subscriber may agree upon
      XML, JSON, MTL, protobufs or any other format.

      L-Data-REQ-06 (IC): I2RS Transports must be able to be chosen by a
      I2RS Client-I2RS Agent pair.  An I2RS Client-I2RS Agent pair
      should be allowed to negotiate the transport options from a list
      of options.

      L-DATA-REQ-07 (IC): The I2RS interface (protocol and IMs) should
      allow a subscribe to select portions of the data model.

      L-Data-REQ-08 (IC): The I2RS interface (protocol and IMs) should
      allow for multiple publish subscriptions at a time.

      L-Data-REQ-09 (IC): Timestaps should be associated with data that
      requires it.  Not all data will require a time stamp.  Additional
      time stamps may be added.

      L-Data-REQ-10 (IC): The I2RS should support the query and
      "introspection" of the data model.  The Introspections provides
      support for data verification, easier inclusion in legacy data,
      and easier merging with data streams.

      L-Data-REQ-11 (IC): After the I2rs Client-Agent have exchanged
      capabilities, a database model, and filters used to select
      elements of the model to subscribe to, the framework should
      support a standard way to register for all the data desired, using
      whatever capabilities were advertised by the node.  Once
      registration is complete, the control channel can be closed.
      Ensuring subscriptions are correct, complete, and replicated or
      not, is up to the overall system and not the agent on the network
      node.

      L-Data-REQ-12 (IC): The I2RS interface should support user
      subscriptions to data with the following parameters:

      *  push of data synchronously or asynchronously via registered
         subscriptions

      *  pull data off in a one-shot pull or in multiple sequences

      *  provide dynamic subscriptions that can be setup via IPFIX feed




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      *  support of subscriber and consumer I2RS Client-agent pairs

      *  allow remapping of a node's databases

      L-Data-REQ-13 (IC): The I2RS interface must handle and report
      errors that occur with data subscription, stale data, repeated
      transport failures, and other (yet unknown) errors

14.  CDNI

   The requirements from the Content Delivery Network Interaction
   described in [I-D.shin-i2rs-usecases-cdni-request-routing] are (OC):

   o  CDNI-REQ-01 (OC): The I2RS interface should support two CDNI
      functionalities [I-D.ietf-cdni-framework]:

      *  Request Routing Interface - Footprint and Capabilities
         Advertisement; the asynchronous advertisement of footprint and
         capabilities by a dCDN that allows a uCDN to decide whether to
         redirect particular user requests to that dCDN via the ALTO
         protocol; and

      *  Request Routing Interface - Redirection; the synchronous
         operation of actually redirecting a user request via I2RS
         manipulation of the routing plane.

   o  CDNI-REQ-02 (OC): The I2RS (Protocol and IM) should provide
      facilities to enable the query/response of information from an
      ALTO services in a node routing functions so that the upstream CDN
      provider can select a proper downstream CDN provider for a given
      end user request.

   o  CDNI-REQ-03 (OC): I2RS (protocol and IM) should provide facilties
      to enable I2RS can help the upstream CDN provider to redirect a
      content request message to a downstream CDN provider for a given
      end user request as with the following features:

      *  The uCDN relays this message between I2RS Clients and I2RS
         agents with content distribution metadata, and queries the dCDN
         whether user request message can be delivered.  This query can
         have multiple dDCN that the user message can be delivered to.

      *  the I2RS agent associated with the dCDN delivery requests
         indicating which dCDN (if any) the user message can be
         delivered to.

      *  Allow dCDN to be managed to deliver content by having the
         messages to signal back to the uCDN the (destination (?)) iP



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         address for the content, on the dCDN, and the pathway between
         the uCDN for surrogate deliver via the dCDN of user data.  Part
         of this management is the passing of URL of the surrogate in
         dCDN (for HTTP Redirection to be transmitting) back from the
         dCDN to the uCDN so the uCDN can inform the end user.

15.  IANA Considerations

   This document makes no request of IANA.

16.  Security Considerations

   Routing information is very critical and sensitive information for
   the operators.  I2RS should provide strong security mechanism to
   protect the routing information that it could not be accessed by the
   un-authorised users.  It should also protect the security and
   integrity protection of the routing data.

17.  References

17.1.  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,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC3746]  Yang, L., Dantu, R., Anderson, T., and R. Gopal,
              "Forwarding and Control Element Separation (ForCES)
              Framework", RFC 3746, DOI 10.17487/RFC3746, April 2004,
              <http://www.rfc-editor.org/info/rfc3746>.

17.2.  Informative References

   [I-D.amante-i2rs-topology-use-cases]
              Medved, J., Previdi, S., Lopez, V., and S. Amante,
              "Topology API Use Cases", draft-amante-i2rs-topology-use-
              cases-01 (work in progress), October 2013.

   [I-D.bitar-i2rs-service-chaining]
              Bitar, N., Heron, G., Fang, L., ramki, r., Leymann, N.,
              Shah, H., and W. Haddad, "Interface to the Routing System
              (I2RS) for Service Chaining: Use Cases and Requirements",
              draft-bitar-i2rs-service-chaining-01 (work in progress),
              February 2014.






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   [I-D.chen-i2rs-mpls-ldp-usecases]
              Chen, X. and Z. Li, "Use Cases for an Interface to LDP
              Protocol", draft-chen-i2rs-mpls-ldp-usecases-00 (work in
              progress), October 2013.

   [I-D.chen-i2rs-ts-use-case]
              Chen, M. and S. Hares, "I2RS Traffic Steering Use Case",
              draft-chen-i2rs-ts-use-case-01 (work in progress), July
              2014.

   [I-D.hares-i2rs-use-case-vn-vc]
              Hares, S. and M. Chen, "Use Cases for Virtual Connections
              on Demand (VCoD) and Virtual Network on Demand (VNoD)
              using Interface to Routing System", draft-hares-i2rs-use-
              case-vn-vc-03 (work in progress), July 2014.

   [I-D.huang-i2rs-mpls-te-usecases]
              Huang, T., Li, Z., and S. Hares, "Use Cases for an
              Interface to MPLS TE", draft-huang-i2rs-mpls-te-
              usecases-02 (work in progress), July 2014.

   [I-D.ietf-i2rs-architecture]
              Atlas, A., Halpern, J., Hares, S., Ward, D., and T.
              Nadeau, "An Architecture for the Interface to the Routing
              System", draft-ietf-i2rs-architecture-15 (work in
              progress), April 2016.

   [I-D.ietf-i2rs-problem-statement]
              Atlas, A., Nadeau, T., and D. Ward, "Interface to the
              Routing System Problem Statement", draft-ietf-i2rs-
              problem-statement-11 (work in progress), May 2016.

   [I-D.ietf-i2rs-rib-info-model]
              Bahadur, N., Kini, S., and J. Medved, "Routing Information
              Base Info Model", draft-ietf-i2rs-rib-info-model-09 (work
              in progress), July 2016.

   [I-D.ietf-sfc-problem-statement]
              Quinn, P. and T. Nadeau, "Service Function Chaining
              Problem Statement", draft-ietf-sfc-problem-statement-13
              (work in progress), February 2015.

   [I-D.ji-i2rs-usecases-ccne-service]
              Ji, X., Zhuang, S., Huang, T., and S. Hares, "I2RS Use
              Cases for Control of Forwarding Path by Central Control
              Network Element (CCNE)", draft-ji-i2rs-usecases-ccne-
              service-02 (work in progress), July 2014.




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   [I-D.keyupate-i2rs-bgp-usecases]
              Patel, K., Fernando, R., Gredler, H., Amante, S., White,
              R., and S. Hares, "Use Cases for an Interface to BGP
              Protocol", draft-keyupate-i2rs-bgp-usecases-04 (work in
              progress), July 2014.

   [I-D.krishnan-i2rs-large-flow-use-case]
              ramki, r., Ghanwani, A., Kini, S., McDysan, D., and D.
              Lopez, "Large Flow Use Cases for I2RS PBR and QoS", draft-
              krishnan-i2rs-large-flow-use-case-04 (work in progress),
              April 2014.

   [I-D.lapukhov-bgp-routing-large-dc]
              Lapukhov, P., Premji, A., and J. Mitchell, "Use of BGP for
              routing in large-scale data centers", draft-lapukhov-bgp-
              routing-large-dc-06 (work in progress), August 2013.

   [I-D.medved-i2rs-topology-requirements]
              Medved, J., Previdi, S., Gredler, H., Nadeau, T., and S.
              Amante, "Topology API Requirements", draft-medved-i2rs-
              topology-requirements-00 (work in progress), February
              2013.

   [I-D.shin-i2rs-usecases-cdni-request-routing]
              Shin, M. and S. Lee, "CDNI Request Routing with I2RS",
              draft-shin-i2rs-usecases-cdni-request-routing-00 (work in
              progress), July 2014.

   [I-D.swhyte-i2rs-data-collection-system]
              Whyte, S., Hines, M., and W. Kumari, "Bulk Network Data
              Collection System", draft-swhyte-i2rs-data-collection-
              system-00 (work in progress), October 2013.

   [I-D.white-i2rs-use-case]
              White, R., Hares, S., and A. Retana, "Protocol Independent
              Use Cases for an Interface to the Routing System", draft-
              white-i2rs-use-case-06 (work in progress), July 2014.

   [I-D.zhang-i2rs-mbb-usecases]
              Zhang, L., Li, Z., Liu, D., and S. Hares, "Use Cases of
              I2RS in Mobile Backhaul Network", draft-zhang-i2rs-mbb-
              usecases-01 (work in progress), February 2014.

   [RFC4655]  Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
              Element (PCE)-Based Architecture", RFC 4655,
              DOI 10.17487/RFC4655, August 2006,
              <http://www.rfc-editor.org/info/rfc4655>.




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   [RFC5212]  Shiomoto, K., Papadimitriou, D., Le Roux, JL., Vigoureux,
              M., and D. Brungard, "Requirements for GMPLS-Based Multi-
              Region and Multi-Layer Networks (MRN/MLN)", RFC 5212,
              DOI 10.17487/RFC5212, July 2008,
              <http://www.rfc-editor.org/info/rfc5212>.

   [RFC5286]  Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for
              IP Fast Reroute: Loop-Free Alternates", RFC 5286,
              DOI 10.17487/RFC5286, September 2008,
              <http://www.rfc-editor.org/info/rfc5286>.

   [RFC5623]  Oki, E., Takeda, T., Le Roux, JL., and A. Farrel,
              "Framework for PCE-Based Inter-Layer MPLS and GMPLS
              Traffic Engineering", RFC 5623, DOI 10.17487/RFC5623,
              September 2009, <http://www.rfc-editor.org/info/rfc5623>.

   [RFC5693]  Seedorf, J. and E. Burger, "Application-Layer Traffic
              Optimization (ALTO) Problem Statement", RFC 5693,
              DOI 10.17487/RFC5693, October 2009,
              <http://www.rfc-editor.org/info/rfc5693>.

Authors' Addresses

   Susan Hares
   Huawei

   Email: shares@ndzh.com


   Mach Chen
   Huawei Technologies
   Huawei Bld., No.156 Beiqing Rd.
   Beijing  100095
   China

   Email: mach.chen@huawei.com















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