Internet DRAFT - draft-ietf-grow-bmp-adj-rib-out
draft-ietf-grow-bmp-adj-rib-out
Global Routing Operations T. Evens
Internet-Draft S. Bayraktar
Updates: 7854 (if approved) Cisco Systems
Intended status: Standards Track P. Lucente
Expires: February 6, 2020 NTT Communications
P. Mi
Tencent
S. Zhuang
Huawei
August 5, 2019
Support for Adj-RIB-Out in BGP Monitoring Protocol (BMP)
draft-ietf-grow-bmp-adj-rib-out-07
Abstract
The BGP Monitoring Protocol (BMP) defines access to only the Adj-RIB-
In Routing Information Bases (RIBs). This document updates the BGP
Monitoring Protocol (BMP) RFC 7854 by adding access to the Adj-RIB-
Out RIBs. It adds a new flag to the peer header to distinguish Adj-
RIB-In and Adj-RIB-Out.
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 February 6, 2020.
Copyright Notice
Copyright (c) 2019 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
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
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publication of this document. Please review these documents
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Per-Peer Header . . . . . . . . . . . . . . . . . . . . . . . 4
5. Adj-RIB-Out . . . . . . . . . . . . . . . . . . . . . . . . . 4
5.1. Post-Policy . . . . . . . . . . . . . . . . . . . . . . . 4
5.2. Pre-Policy . . . . . . . . . . . . . . . . . . . . . . . 5
6. BMP Messages . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Route Monitoring and Route Mirroring . . . . . . . . . . 5
6.2. Statistics Report . . . . . . . . . . . . . . . . . . . . 5
6.3. Peer Down and Up Notifications . . . . . . . . . . . . . 6
6.3.1. Peer Up Information . . . . . . . . . . . . . . . . . 6
7. Other Considerations . . . . . . . . . . . . . . . . . . . . 6
7.1. Peer and Update Groups . . . . . . . . . . . . . . . . . 7
8. Security Considerations . . . . . . . . . . . . . . . . . . . 7
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
9.1. BMP Peer Flags . . . . . . . . . . . . . . . . . . . . . 8
9.2. BMP Statistics Types . . . . . . . . . . . . . . . . . . 8
9.3. Peer Up Information TLV . . . . . . . . . . . . . . . . . 8
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
10.1. Normative References . . . . . . . . . . . . . . . . . . 9
10.2. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 9
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
BGP Monitoring Protocol (BMP) defines monitoring of the received
(e.g., Adj-RIB-In) Routing Information Bases (RIBs) per peer. The
Adj-RIB-In pre-policy conveys to a BMP receiver all RIB data before
any policy has been applied. The Adj-RIB-In post-policy conveys to a
BMP receiver all RIB data after policy filters and/or modifications
have been applied. An example of pre-policy versus post-policy is
when an inbound policy applies attribute modification or filters.
Pre-policy would contain information prior to the inbound policy
changes or filters of data. Post policy would convey the changed
data or would not contain the filtered data.
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Monitoring the received updates that the router received before any
policy has been applied is the primary level of monitoring for most
use-cases. Inbound policy validation and auditing is the primary
use-case for enabling post-policy monitoring.
In order for a BMP receiver to receive any BGP data, the BMP sender
(e.g., router) needs to have an established BGP peering session and
actively be receiving updates for an Adj-RIB-In.
Being able to only monitor the Adj-RIB-In puts a restriction on what
data is available to BMP receivers via BMP senders (e.g., routers).
This is an issue when the receiving end of the BGP peer is not
enabled for BMP or when it is not accessible for administrative
reasons. For example, a service provider advertises prefixes to a
customer, but the service provider cannot see what it advertises via
BMP. Asking the customer to enable BMP and monitoring of the Adj-
RIB-In is not feasible.
BGP Monitoring Protocol (BMP) RFC 7854 [RFC7854] only defines Adj-
RIB-In being sent to BMP receivers. This document updates the per-
peer header in section 4.2 of [RFC7854] by adding a new flag to
distinguish Adj-RIB-In versus Adj-RIB-Out. BMP senders use the new
flag to send either Adj-RIB-In or Adj-RIB-Out.
Adding Adj-RIB-Out provides the ability for a BMP sender to send to
BMP receivers what it advertises to BGP peers, which can be used for
outbound policy validation and to monitor routes that were
advertised.
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. Definitions
o Adj-RIB-Out: As defined in [RFC4271], "The Adj-RIBs-Out contains
the routes for advertisement to specific peers by means of the
local speaker's UPDATE messages."
o Pre-Policy Adj-RIB-Out: The result before applying the outbound
policy to an Adj-RIB-Out. This normally would match what is in the
local RIB.
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o Post-Policy Adj-RIB-Out: The result of applying outbound policy to
an Adj-RIB-Out. This MUST convey to the BMP receiver what is
actually transmitted to the peer.
4. Per-Peer Header
The per-peer header has the same structure and flags as defined in
section 4.2 of [RFC7854] with the following O flag addition:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|V|L|A|O| Resv |
+-+-+-+-+-+-+-+-+
o The O flag indicates Adj-RIB-In if set to 0 and Adj-RIB-Out if set
to 1.
The existing flags are defined in section 4.2 of [RFC7854] and the
remaining bits are reserved for future use. They MUST be transmitted
as 0 and their values MUST be ignored on receipt.
When the O flag is set to 1, the following fields in the Per-Peer
Header are redefined:
o Peer Address: The remote IP address associated with the TCP
session over which the encapsulated PDU is sent.
o Peer AS: The Autonomous System number of the peer to which the
encapsulated PDU is sent.
o Peer BGP ID: The BGP Identifier of the peer to which the
encapsulated PDU is sent.
o Timestamp: The time when the encapsulated routes were advertised
(one may also think of this as the time when they were installed
in the Adj-RIB-Out), expressed in seconds and microseconds since
midnight (zero hour), January 1, 1970 (UTC). If zero, the time is
unavailable. Precision of the timestamp is implementation-
dependent.
5. Adj-RIB-Out
5.1. Post-Policy
The primary use-case in monitoring Adj-RIB-Out is to monitor the
updates transmitted to a BGP peer after outbound policy has been
applied. These updates reflect the result after modifications and
filters have been applied (e.g., Adj-RIB-Out Post-Policy). Some
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attributes are set when the BGP message is transmitted, such as next-
hop. Adj-RIB-Out Post-Policy MUST convey to the BMP receiver what is
actually transmitted to the peer.
The L flag MUST be set to 1 to indicate post-policy.
5.2. Pre-Policy
Similarly to Adj-RIB-In policy validation, pre-policy Adj-RIB-Out can
be used to validate and audit outbound policies. For example, a
comparison between pre-policy and post-policy can be used to validate
the outbound policy.
Depending on BGP peering session type (IBGP, IBGP route reflector
client, EBGP, BGP confederations, Route Server Client) the candidate
routes that make up the Pre-Policy Adj-RIB-Out do not contain all
local-rib routes. Pre-Policy Adj-RIB-Out conveys only routes that
are available based on the peering type. Post-Policy represents the
filtered/changed routes from the available routes.
Some attributes are set only during transmission of the BGP message,
i.e., Post-Policy. It is common that next-hop may be null, loopback,
or similar during pre-policy phase. All mandatory attributes, such
as next-hop, MUST be either ZERO or have an empty length if they are
unknown at the Pre-Policy phase completion. The BMP receiver will
treat zero or empty mandatory attributes as self-originated.
The L flag MUST be set to 0 to indicate pre-policy.
6. BMP Messages
Many BMP messages have a per-peer header but some are not applicable
to Adj-RIB-In or Adj-RIB-Out monitoring, such as peer up and down
notifications. Unless otherwise defined, the O flag should be set to
0 in the per-peer header in BMP messages.
6.1. Route Monitoring and Route Mirroring
The O flag MUST be set accordingly to indicate if the route monitor
or route mirroring message conveys Adj-RIB-In or Adj-RIB-Out.
6.2. Statistics Report
The Statistics report message has a Stat Type field to indicate the
statistic carried in the Stat Data field. Statistics report messages
are not specific to Adj-RIB-In or Adj-RIB-Out and MUST have the O
flag set to zero. The O flag SHOULD be ignored by the BMP receiver.
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The following new statistic types are added:
o Stat Type = 14: (64-bit Gauge) Number of routes in Adj-RIBs-Out
Pre-Policy.
o Stat Type = 15: (64-bit Gauge) Number of routes in Adj-RIBs-Out
Post-Policy.
o Stat Type = 16: Number of routes in per-AFI/SAFI Adj-RIB-Out Pre-
Policy. The value is structured as: 2-byte Address Family
Identifier (AFI), 1-byte Subsequent Address Family Identifier
(SAFI), followed by a 64-bit Gauge.
o Stat Type = 17: Number of routes in per-AFI/SAFI Adj-RIB-Out Post-
Policy. The value is structured as: 2-byte Address Family
Identifier (AFI), 1-byte Subsequent Address Family Identifier
(SAFI), followed by a 64-bit Gauge.
6.3. Peer Down and Up Notifications
Peer Up and Down notifications convey BGP peering session state to
BMP receivers. The state is independent of whether or not route
monitoring or route mirroring messages will be sent for Adj-RIB-In,
Adj-RIB-Out, or both. BMP receiver implementations SHOULD ignore the
O flag in Peer Up and Down notifications.
6.3.1. Peer Up Information
The following Peer Up message Information TLV type is added:
o Type = 4: Admin Label. The Information field contains a free-form
UTF-8 string whose byte length is given by the Information Length
field. The value is administratively assigned. There is no
requirement to terminate the string with null or any other
character.
Multiple admin labels can be included in the Peer Up notification.
When multiple admin labels are included the BMP receiver MUST
preserve their order.
The TLV is optional.
7. Other Considerations
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7.1. Peer and Update Groups
Peer and update groups are used to group updates shared by many
peers. This is a level of efficiency in implementations, not a true
representation of what is conveyed to a peer in either Pre-Policy or
Post-Policy.
One of the use-cases to monitor Adj-RIB-Out Post-Policy is to
validate and continually ensure the egress updates match what is
expected. For example, wholesale peers should never have routes with
community X:Y sent to them. In this use-case, there may be hundreds
of wholesale peers but a single peer could have represented the
group.
From a BMP perspective, this should be simple to include a group name
in the Peer Up, but it is more complex than that. BGP
implementations have evolved to provide comprehensive and structured
policy grouping, such as session, AFI/SAFI, and template-based based
group policy inheritances.
This level of structure and inheritance of polices does not provide a
simple peer group name or ID, such as wholesale peer.
Instead of requiring a group name to be used, a new administrative
label informational TLV (Section 6.3.1) is added to the Peer Up
message. These labels have administrative scope relevance. For
example, labels "type=wholesale" and "region=west" could be used to
monitor expected policies.
Configuration and assignment of labels to peers is BGP implementation
specific.
8. Security Considerations
The same considerations as in section 11 of [RFC7854] apply to this
document. Implementations of this protocol SHOULD require to
establish sessions with authorized and trusted monitoring devices.
It is also believed that this document does not add any additional
security considerations.
9. IANA Considerations
This document requests that IANA assign the following new parameters
to the BMP parameters name space [1].
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9.1. BMP Peer Flags
This document defines the following per-peer header flags
(Section 4):
o Flag 3 as O flag: The O flag indicates Adj-RIB-In if set to 0 and
Adj-RIB-Out if set to 1.
9.2. BMP Statistics Types
This document defines four statistic types for statistics reporting
(Section 6.2):
o Stat Type = 14: (64-bit Gauge) Number of routes in Adj-RIBs-Out
Pre-Policy.
o Stat Type = 15: (64-bit Gauge) Number of routes in Adj-RIBs-Out
Post-Policy.
o Stat Type = 16: Number of routes in per-AFI/SAFI Adj-RIB-Out Pre-
Policy. The value is structured as: 2-byte Address Family
Identifier (AFI), 1-byte Subsequent Address Family Identifier
(SAFI), followed by a 64-bit Gauge.
o Stat Type = 17: Number of routes in per-AFI/SAFI Adj-RIB-Out Post-
Policy. The value is structured as: 2-byte Address Family
Identifier (AFI), 1-byte Subsequent Address Family Identifier
(SAFI), followed by a 64-bit Gauge.
9.3. Peer Up Information TLV
This document defines the following BMP Peer Up Information TLV types
(Section 6.3.1):
o Type = 4: Admin Label. The Information field contains a free-form
UTF-8 string whose byte length is given by the Information Length
field. The value is administratively assigned. There is no
requirement to terminate the string with null or any other
character.
Multiple admin labels can be included in the Peer Up notification.
When multiple admin labels are included the BMP receiver MUST
preserve their order.
The TLV is optional.
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10. References
10.1. 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,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/info/rfc4271>.
[RFC7854] Scudder, J., Ed., Fernando, R., and S. Stuart, "BGP
Monitoring Protocol (BMP)", RFC 7854,
DOI 10.17487/RFC7854, June 2016,
<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,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
10.2. URIs
[1] https://www.iana.org/assignments/bmp-parameters/bmp-
parameters.xhtml
Acknowledgements
The authors would like to thank John Scudder and Mukul Srivastava for
their valuable input.
Contributors
Manish Bhardwaj
Cisco Systems
3700 Cisco Way
San Jose, CA 95134
USA
Email: manbhard@cisco.com
Xianyuzheng
Tencent
Tencent Building, Kejizhongyi Avenue,
Hi-techPark, Nanshan District,Shenzhen 518057, P.R.China
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Weiguo
Tencent
Tencent Building, Kejizhongyi Avenue,
Hi-techPark, Nanshan District,Shenzhen 518057, P.R.China
Shugang cheng
H3C
Authors' Addresses
Tim Evens
Cisco Systems
2901 Third Avenue, Suite 600
Seattle, WA 98121
USA
Email: tievens@cisco.com
Serpil Bayraktar
Cisco Systems
3700 Cisco Way
San Jose, CA 95134
USA
Email: serpil@cisco.com
Paolo Lucente
NTT Communications
Siriusdreef 70-72
Hoofddorp, WT 2132
NL
Email: paolo@ntt.net
Penghui Mi
Tencent
Tengyun Building,Tower A ,No. 397 Tianlin Road
Shanghai 200233
China
Email: kevinmi@tencent.com
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Shunwan Zhuang
Huawei
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: zhuangshunwan@huawei.com
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