Internet-Draft Filtering Adj-Rib-In and Adj-Rib-Out to July 2024
Lucente, et al. Expires 24 January 2025 [Page]
Workgroup:
Global Routing Operations
Internet-Draft:
draft-pcmy-grow-bmp-adj-ribs-filtered-00
Updates:
7854 (if approved)
Published:
Intended Status:
Standards Track
Expires:
Authors:
P. Lucente
NTT
C. Cardona
NTT
M. Srivastava
Juniper Networks

Filtering Adj-Rib-In and Adj-Rib-Out to BMP receivers

Abstract

Filtering RIBs in BMP (BGP Monitoring Protocol) can be desirable for several use-cases like, for example, limiting the amount of data a collector station has to process or allow a sender to export only a certain afi/safi of interest. This document defines a light way to inform a collector station that a Adj-Rib-In / Adj-Rib-Out data feed is being filtered.

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 24 January 2025.

Table of Contents

1. Introduction

While RFC9069 [RFC9069] does define a light way to mark a Loc-Rib as filtered, there is no equivalent mechanism for Adj-Rib-In RFC7854 [RFC7854] and Adj-Rib-Out RFC8671 [RFC8671]. This can be easily addressed through the introduction of a Peer F Flag in the "BMP Peer Flags for Peer Types 0 through 2" registry.

2. Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 RFC 2119 [RFC2119] RFC 8174 [RFC8174] when, and only when, they appear in all capitals, as shown here.

3. Filtered RIB Flag

As a recap, a BMP session is regarded as carrying Adj-Rib-In by defining the Peer Type to 0, 1 or 2 values and setting the O flag to zero (0) in the BMP Peer Flags (for Peer Types 0 through 2) registry. Similarly, Adj-Rib-Out is set by defining the Peer Type to 0, 1 or 2 values and setting the O flag to one (1) in the BMP Peer Flags (for Peer Types 0 through 2) registry. Both Adj-Rib-In and Adj-Rib-Out can be further defined as Pre-Policy, setting the Peer L Flag to zero (0), or Post-Policy, setting the Peer L Flag to one (1).

For both Adj-Rib-In and Adj-Rib-Out, for both Pre-Policy and Post-Policy cases, a new Peer F Flag is defined in the "BMP Peer Flags for Peer Types 0 through 2" registry. If the RIB was filtered, the flag MUST be set to one (1).

In Stats messages, counts MUST reflect the filtered RIB numbers and not the original RIB ones.

Also should any characteristic of the filtering change, the sender MUST trigger a Peer Down then followed by a new Peer Up.

4. Operational Considerations

It is recommended that when filtering RIBs, the VRF/Table Name TLV - as defined in RFC9069 [RFC9069], TLV support for BMP Route Monitoring and Peer Down Messages [I-D.ietf-grow-bmp-tlv] and BMP Peer Up Namespace [I-D.ietf-grow-bmp-peer-up] - is specified to a meaningful string that can help discriminate the nature of filtering.

The VRF/Table Name TLV can be either set in the Peer Up message, so to implicitely apply to all NLRIs received by the peer, or set via a Group TLV in Route Monitoring messages, to esplicitely apply to all NLRIs in the group. Going down the Peer Up model is certainly optimal on the wire and simplifies packing at the sender side; going down the Route Monitoring model, instead, allows the receiver side to operate non-contextually (ie. no need to look back at the Peer Up to make due associations).

5. Security Considerations

It is not believed that this document adds any additional security considerations.

6. IANA Considerations

This document asks IANA to add a new F Flag to the "BMP Peer Flags for Peer Types 0 through 2" registry. The recommended value for the registry is 4.

7. Normative References

[I-D.ietf-grow-bmp-peer-up]
Scudder, J. and P. Lucente, "BMP Peer Up Message Namespace", Work in Progress, Internet-Draft, draft-ietf-grow-bmp-peer-up-04, , <https://datatracker.ietf.org/doc/html/draft-ietf-grow-bmp-peer-up-04>.
[I-D.ietf-grow-bmp-tlv]
Lucente, P. and Y. Gu, "BMP v4: TLV support for BMP Route Monitoring and Peer Down Messages", Work in Progress, Internet-Draft, draft-ietf-grow-bmp-tlv-14, , <https://datatracker.ietf.org/doc/html/draft-ietf-grow-bmp-tlv-14>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
[RFC7854]
Scudder, J., Ed., Fernando, R., and S. Stuart, "BGP Monitoring Protocol (BMP)", RFC 7854, DOI 10.17487/RFC7854, , <https://www.rfc-editor.org/info/rfc7854>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
[RFC8671]
Evens, T., Bayraktar, S., Lucente, P., Mi, P., and S. Zhuang, "Support for Adj-RIB-Out in the BGP Monitoring Protocol (BMP)", RFC 8671, DOI 10.17487/RFC8671, , <https://www.rfc-editor.org/info/rfc8671>.
[RFC9069]
Evens, T., Bayraktar, S., Bhardwaj, M., and P. Lucente, "Support for Local RIB in the BGP Monitoring Protocol (BMP)", RFC 9069, DOI 10.17487/RFC9069, , <https://www.rfc-editor.org/info/rfc9069>.

Acknowledgements

The authors would like to thank Jeff Haas for his valuable input.

Authors' Addresses

Paolo Lucente
NTT
Veemweg 23
3771 Barneveld
Netherlands
Camilo Cardona
NTT
164-168, Carrer de Numancia
08029 Barcelona
Spain
Mukul Srivastava
Juniper Networks
10 Technology Park Dr
Westford, MA 01886
United States of America