Filtering Out RPKI Data by Type based on Enhanced SLURM Filters

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Table of Contents

1. Introduction

Relying Party (RP) collects signed RPKI objects from global RPKI publication points. The RPKI data passing RP's validation will appear in RP's output. Then, the RPKI-to-Router (RTR) protocol [RFC6810][RFC8210][I-D.ietf-sidrops-8210bis] will synchronize the validated RPKI data from RP to routers. Currently, four types of RPKI data including IPv4 Prefix, IPv6 Prefix, Router Key, and ASPA are supported in the RTR protocol.¶

However, in some cases, routers may be interested in a part of RPKI data types, instead of all [I-D.geng-sidrops-rtr-selective-sync]. In such cases, storing unused data on the router is unreasonable, and synchronizing all types of data will induce some unnecessary transmission and storage overhead. Besides, multiple types of data can be transmitted together. The router cannot use any type of these data unless it waits for all data to complete transmission.¶

Furthermore, there may be more types of RPKI data in the RPKI repositories and RPs, which makes the above problem more significant and worse. The followings are example types, and some of them may be possibly supported in the RPKI system in the future:¶

• Secured Routing Policy Specification Language (RPSL) [RFC7909]¶

• Signed Prefix Lists [I-D.ietf-sidrops-rpki-prefixlist]¶

• Autonomous Systems Cones [I-D.ietf-grow-rpki-as-cones]¶

• Mapping Origin Authorizations (MOAs) [I-D.xie-sidrops-moa-profile]¶

• Signed SAVNET-Peering Information (SiSPI) [I-D.chen-sidrops-sispi]¶

• Path validation with RPKI [I-D.van-beijnum-sidrops-pathrpki]¶

• Signed Groupings of Autonomous System Numbers [I-D.spaghetti-sidrops-rpki-asgroup]¶

To deal with the problem, configuring routers directly ignoring the uninterested RPKI data transmitted by RTR protocol may not be a good solution. While storage overhead is avoided, transmission delay is not optimized. Extending RTR protocol for supporting selective synchronization of RPKI data is an alternative solution [I-D.geng-sidrops-rtr-selective-sync]. Both of the two solutions require the upgrade of router software.¶

SLURM provides a simple way to enable an RP to establish a local and customized view of the RPKI ([RFC8416], [I-D.ietf-sidrops-aspa-slurm]). It defines Validation Output Filters to filter out specific RPKI data items and Locally Added Assertions to add RPKI data items. Unfortunately, SLURM cannot efficiently filter out RPKI data by type, i.e., filter out all the RPKI data belonging to a specific type.¶

This document proposes enhanced SLURM filters which can filter out RPKI data by type. With enhanced SLURM filters, operators can efficiently select which type of RPKI data need to be synchronized to routers.¶

The proposed method requires some modifications on the SLURM-related process of RP software. Upgrades of RTR implementations and router software implementations are not involved.¶

2. Use Case

One of use cases is IPv6-only network. Suppose a IPv6-only network wants to enable ROV on BGP border routers. The routers should be only interested in IPv6-related BGP validation because the routers can only receive IPv6 routes from neighbor ASes. Therefore, IPv4 Prefix data is not useful for the network. An example of IPv6-only network is New China Education and Research Network (named Future Internet Technology Infrastructure, FITI).¶

                  +------------+
                  | Rely Party |
                  +------------+
                   /          \
                  / Sync RPKI  \
                 /  data by RTR \
      +---------/----------------\---------+
IPv6  |        /                  \        |IPv6
routes| +----------+          +----------+ |routes
------->|BGP router|          |BGP router| |------>
      | +----------+          +----------+ |
      |             IPv6-only              |
      +------------------------------------+

As described in Section 1, there may be more types of RPKI data in the RPKI repositories and RPs. Thus, there will be more use cases where a network does not need all types of RPKI data in the future.¶

3. Enhanced SLURM Filters

This section proposes two optional designs.¶

  {
    "slurmVersion": 2,
    "validationOutputFilters": {
      "aspaFilters": [],
      "bgpsecFilters": [],
      "prefixFilters": [],
      "typeFilters": []
    },
    "locallyAddedAssertions": {
      "aspaAssertions": [],
      "bgpsecAssertions": [],
      "prefixAssertions": []
    }
  }

  "typeFilter": [
    {
      "rpkiDataType": "IPv4 Prefix",
      "comment": "Filter out VRPs with IPv4 Prefixes"
    }
  ]

  "prefixFilters": [
    {
      "asn": 65535,
      "comment": "Filter out VRPs with IPv4 and IPv6 Prefixes"
    }
  ]

4. Security Considerations

The security considerations in Section 6 of [RFC8416] are also applied to this document.¶

5. IANA Considerations

This document has no IANA actions.¶

Acknowledgements

TBD¶

Authors' Addresses