BMP Loc-RIB: Peer address
draft-francois-grow-bmp-loc-peer-01
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| Document | Type |
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|---|---|---|---|
| Authors | Pierre Francois , Maxence Younsi , Paolo Lucente | ||
| Last updated | 2023-07-10 (Latest revision 2023-03-13) | ||
| Replaced by | draft-ietf-grow-bmp-loc-peer | ||
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draft-francois-grow-bmp-loc-peer-01
Network Working Group P. Francois
Internet-Draft M. Younsi
Updates: 9069 (if approved) INSA-Lyon
Intended status: Standards Track P. Lucente
Expires: 11 January 2024 NTT
10 July 2023
BMP Loc-RIB: Peer address
draft-francois-grow-bmp-loc-peer-01
Abstract
BMP Loc-RIB lets a BMP publisher set the Peer Address value of a path
information to zero. This document introduces the option to
communicate the actual peer from which a path was received when
advertising that path with BMP Loc-RIB.
Requirements Language
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 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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
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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 11 January 2024.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. BMPv3 Behavior . . . . . . . . . . . . . . . . . . . . . . . 2
3. BMPv4 TLV Based Behavior . . . . . . . . . . . . . . . . . . 3
3.1. Rx Peer-Address TLV . . . . . . . . . . . . . . . . . . . 3
3.2. VRF Import TLV . . . . . . . . . . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
Using BMP Loc-RIB [RFC9069], the Peer Address field of a Per-Peer
header is Zero-filled. This prevents a collector from knowing from
which peer a path selected as best was received. The nexthop
attribute of a path is indeed not an identifier of the peer from
which the path was received. Knowing the peer address is also
especially useful when Loc-RIB paths come from Add-Path enabled peers
as the path ID space of paths are defined per peer.
This document introduces the option to actually set this field to the
IP Address of the peer from which the installed path was received.
For BMPv4, it introduces a TLV describing the Peer Address.
2. BMPv3 Behavior
A BMPv3 Loc-RIB enabled node following this specification sets the
Peer Address field in the Per-Peer header to the address of the Peer
from which this path was received.
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|F|V| | | | | | |
+-+-+-+-+-+-+-+-+
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Figure 1: Per-peer flags
A flag is introduced in the BMP Loc-RIB per-peer header flags to
describe whether the peer address is IPv4 or IPv6.
If the peer address is an IPv6 address, the V flag MUST be set to 1.
If the peer address is an IPv4 address, the V flag MUST be set to 0.
This behavior SHOULD be disabled by default and enabled through
configuration, so that a defensive BMP receiver not supporting this
document would not terminate a BMP session over which it receives a
BMP Loc-RIB messages with a non-zero Peer Address field. This
behavior can be enabled when the operator knows that the receiver can
receive BMP Loc-RIB messages following this specification.
3. BMPv4 TLV Based Behavior
In this section, we describe a variant of the solution based on BMPv4
TLVs. Section 3.1 describes a BMPv4 TLV used to convey the peer
address. Section 3.2 introduces optional TLVs for the case of paths
imported from another VRF.
3.1. Rx Peer-Address TLV
In BMP v4 [I-D.ietf-grow-bmp-tlv], TLV's can be used to provide
optional information along with monitored paths. Peer Address
information can be included using one such TLV.
A TLV type "Rx Peer-Address TLV" needs to be reserved from the BMP
Route Monitoring TLVs registry. The length field is 4 when the peer
is IPv4 and 16 when the peer is IPv6, as the index field of the TLV
is not included in the length field. The value is the IP address of
the peer from which the monitored path was received.
The Rx Peer-Address TLV may describe a self originated path by
setting the value of the peer address to 0. The length of such a
zero filled Peer-Address TLV SHOULD be either 4 or 16.
3.2. VRF Import TLV
Path information advertised through BMP Loc-RIB might be related to a
path imported from another VRF. In that scenario, the sole knowledge
of the remote peer IP address is not sufficient to obtain a clear
picture of where this path was coming from.
A TLV type "Origin VRF TLV" needs to be reserved from the BMP Route
Monitoring TLVs registry. It describes the VRF context in which this
path was received from a peer or where it was self-originated. It
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contains a variable length field matching the definition of VRF/
Table name from [RFC9069]. The length field of this BMPv4 TLV is the
length of the UTF-8 string of the VRF name. When this TLV is
present, the Rx Peer-Address TLV associated with that path refers to
the IP address of the peer from which it was received, in the VRF
context refered in this TLV.
A TLV type "Previous VRF TLV" needs to be reserved from the BMP Route
Monitoring TLVs registry. It describes the VRF from which this path
was imported. It contains a variable length field matching the
definition of VRF/Table name from [RFC9069]. The length field of
this BMPv4 TLV is the length of the UTF-8 string of the VRF name.
As an example, if BMP Loc-RIB describes a path P in VRF C, which was
received from a peer I in VRF A, imported into VRF B, and finally
imported from VRF B into VRF C, the Origin VRF Name is A, the
Previous VRF Name is B, the VRF/Table Name TLV (as per [RFC9069] is
C, and the Rx Peer-Adress TLV is I.
A TLV type "Previous VRF sequence" needs to be reserved from the BMP
Route Monitoring TLVs registry. It describes the entire chain of
VRFs through which this path was imported before landing in the
current VRF. The list starts with the previous VRF, and ends with
the Origin VRF in which this path was received or originated. One
entry of this list has the format described in Figure Figure 2. The
length field is an 8 bit value capturing the length of the Name
field. The name field is the UTF-8 string of the VRF name of the
described VRF of the sequence.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | Name
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ ~
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: VRF sequence entry
The length of a "Previous VRF sequence" TLV is the number of elements
of the sequence + the sum of the sizes of the VRF names of the
sequence.
In the exemple above, the sequence listed in the Previous VRF
sequence would be [B, A].
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4. IANA Considerations
This document requires IANA to reserve Flag 1 in the, described as "V
Flag", with this document as reference, in the BMP Peer Flags for
Loc-RIB Instance Peer Type 3 registry of BGP Monitoring Protocol
(BMP) Parameters.
5. Security Considerations
This document does not introduce new security considerations.
6. Acknowledgements
We would like to thank Camilo Cardona, Jeff Haas, for their valuable
input on this document.
7. References
7.1. Normative References
[I-D.ietf-grow-bmp-tlv]
Lucente, P. and Y. Gu, "TLV support for BMP Route
Monitoring and Peer Down Messages", Work in Progress,
Internet-Draft, draft-ietf-grow-bmp-tlv-10, 8 November
2022, <https://datatracker.ietf.org/doc/html/draft-ietf-
grow-bmp-tlv-10>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[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, February 2022,
<https://www.rfc-editor.org/info/rfc9069>.
7.2. Informative References
Authors' Addresses
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Pierre Francois
INSA-Lyon
Villeurbanne
France
Email: pierre.francois@insa-lyon.fr
Maxence Younsi
INSA-Lyon
Villeurbanne
France
Email: maxence.younsi@insa-lyon.fr
Paolo Lucente
NTT
Siriusdreef 70-72
Hoofddorp, WT 2132
Netherlands
Email: paolo@ntt.net
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