The 'via' keyword in RPSL Policy Specifications
draft-snijders-rpsl-via-00

Abstract

This document defines the 'via' keyword which can be used in RPSL policy specifications to publish desired routing policy regarding non-adjacent networks.

Status of This Memo

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

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This Internet-Draft will expire on December 06, 2013.

Copyright Notice

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Table of Contents

• 1. Introduction
• 2. Notational Conventions
• 3. Background
• 4. Import and Export Via Syntax and Semantics
• 5. Example Usage
• 6. Security Considerations
• 7. IANA Considerations
• 8. Acknowledgments
• 9. References
• 9.1. Normative References
• 9.2. Informative References
• Appendix A. Grammar Rules
• Appendix B. Support and Commitment
• Appendix C. Document Change Log
• Authors' Addresses

1. Introduction

The Routing Policy Specification Language [RFC4012] allows operators to specify routing policies regarding directly adjacent networks through various import and export attributes. These attributes only apply to directly adjacent networks.

This document proposes to extend RPSL according to the following goals and requirements:

• Provide a way to describe what an adjacent network could use as routing policy towards its adjacent networks.
• The extension should be backward compatible with minimal impact on existing tools and processes, following Section 10 of [RFC2622].

The addition of a 'via' keyword in import and export related attributes will especially help participants of Multi-Lateral Peering services to inform the intermediate autonomous system what routing policy should be applied towards other participants.

2. Notational Conventions

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

3. Background

The via keyword specifically benefits operators whom were assigned a 32 bit AS Number and transit providers when participating in Multi-Lateral Peering Agreements facilitated by a Route Server.

Often Route Server operators overload BGP Communities [RFC1997]) to facilitate signalling of desired routing policy between the participants and the Route Server. Because BGP Communities have a length of 32 bit, it is not possible to signal a 32 bit AS Number coupled with an action. In practise this means Route Server participants whom use a 32 bit AS Number cannot specifically be included or excluded during path distribution calculations on the Route Server unless a mapping system is applied.

Transit providers often uphold a routing policy which intents that the transit provider does not want to exchange paths with its downstream customers through Route Servers. The via keyword allows transit providers to participate in Multi-Lateral Peering services while instructing Route Server operators through a simple routing policy specification that paths should not be distributed to downstream customers and reducing the likelyhood of Path Hiding on the Route Server.

4. Import and Export Via Syntax and Semantics

Attribute  Value                                         Type
import     [protocol <protocol-1>] [into <protocol-2>]   optional,
           [via <peering-1>]                             optional,
           from <peering-2> [action <action-1>]
           . . .
           [via <peering-3>]                             optional,
           from <peering-N> [action <action-N>]
           accept <filter>
export     [protocol <protocol-1>] [into <protocol-2>]   optional,
           [via <peering-1>]                             optional,
           to <peering-2> [action <action-1>]             
           . . .
           [via <peering-3>]                             optional,
           to <peering-N> [action <action-N>]
           announce <filter>

mp-import  [protocol <protocol-1>] [into <protocol-2>]   optional,
           [afi <afi-list>]                              multi-valued
           [via <peering-1>]                             optional,
           from <mp-peering-2> [action <action-1>; ... <action-N>;]
           . . .
           [via <peering-3>]                             optional,
           from <mp-peering-M> [action <action-1>; ... <action-N>;]
           accept <mp-filter> [;]

mp-export  [protocol <protocol-1>] [into <protocol-2>]   optional,
           [afi <afi-list>]                              multi-valued
           [via peering-1>]                              optional,
           to <mp-peering-2> [action <action-1>; ... <action-N>;]
           . . .
           [via peering-3>]                              optional,
           to <mp-peering-M> [action <action-1>; ... <action-N>;]
           announce <mp-filter> [;]

          

   aut-num: AS5580
   import: via AS6777
                from AS15562
                action pref = 2;
                accept AS-SNIJDERS
   import: via AS6777
                from AS5580:AS-CUSTOMERS
                accept NOT ANY
   import: via AS6777 from AS15562
                from AS1
                from AS2
                via AS3 from AS4
                accept PeerAS
   mp-import: afi ipv6.unicast via AS6777 
                from AS15562 accept AS-SNIJDERS
   mp-import: via AS6777
                from AS65551 accept AS-SET-FROM-32BIT-ASN
   export: via AS6777
                to AS15562 action community.={5580:40};
                announce AS-ATRATO
   export: via AS5580:AS-ROUTESERVERS
                to AS5580:AS-CUSTOMERS announce NOT ANY
   mp-export: afi ipv6.unicast via AS6777
                to AS15562 announce AS-ATRATO
   mp-export: via AS6777
                to AS65551 announce AS-ATRATO