BMP for BGP Route Leak Detection
draft-gu-grow-bmp-route-leak-detection-00
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| Authors | Yunan Gu , Shunwan Zhuang | ||
| Last updated | 2018-10-22 | ||
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draft-gu-grow-bmp-route-leak-detection-00
Network Working Group Y. Gu
Internet-Draft S. Zhuang
Intended status: Standards Track Huawei
Expires: April 25, 2019 October 22, 2018
BMP for BGP Route Leak Detection
draft-gu-grow-bmp-route-leak-detection-00
Abstract
According to RFC7908 [RFC7908], Route leaks refer to case that the
delivery range of route advertisements is beyond the expected range.
For many current security protection solutions, the ISPs (Internet
Service Providers) are focusing on finding ways to detect the
happening of route leaks. However, the real-time route leak
detection if any occurs is important as well. This document extends
the BGP Monitoring Protocol (BMP) [RFC7854] to provide a routing
security scheme suitable for ISPs to detect BGP route leaks within
their own networks.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
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 April 25, 2019.
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Copyright Notice
Copyright (c) 2018 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
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. ISP Route Leak Prevention Methods . . . . . . . . . . . . 3
2.2. Challenge of the Current Route Leak Prevention Methods . 4
3. Existing RLD Methods Discussion . . . . . . . . . . . . . . . 4
4. BMP Extension for RLD . . . . . . . . . . . . . . . . . . . . 5
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7. Security Considerations . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . 7
8.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Terminology
BMP: BGP Monitoring Protocol
BMS: BGP Monitoring Station
C2P: Customer to Provider
ISP: Internet Service Provider
P2P: Peer to Peer
RIB: Routing Information Base
RLD: Route Leak Detection
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2. Introduction
RFC 7908 defines "Route Leak" as: A route leak is the propagation of
routing announcement(s) beyond their intended scope, which can result
in possible situations such as eavesdropping, device overload, route
black hole and so on. More specifically, the intended scope of route
announcements is usually defined by local route filtering/
distribution policies within devices. These policies are designed to
realise the pair-wise peering business relationships between ASes
(autonomous systems), which include Customer to Provider (C2P), Peer
to Peer (Peer to Peer), and Provider to Customer (P2C). In a C2P
relationship, the customer pays the provider for traffic sent between
the two ASes. In return, the customer gains access to the ASes the
provider can reach, including those which the provider reaches
through its own providers. In a P2P relationship, the peering ASes
gain access to each other's customers, typically without either AS
paying the other[Luckie]. RFC 7908 classifies six typical route
leaks situations based on the documented events.
2.1. ISP Route Leak Prevention Methods
Since BGP itself does not provide any route leak prevention/
protection, in the current networks, network administrators/operators
typically configure export policies on the AS border routers (ASBRs)
to prevent route leak. For example, refer to the topology in
Figure 1, an export policy is configured at ASBR R2 of AS1. The
export strategy is, for example, "routes from AS2 can be sent to AS3
and cannot be sent to AS4." After ASBR R1 of AS1 receives a route A
from AS2, R1 marks A with BGP community attribute stating that route
A is received from AS2. Then route A with this tag is transmitted to
another ASBR R2 through the intermediate node of AS1. Now at ASBR
R2, it checks the export filter/policy to determine if Route A with
the tag is allowed to be distributed to a certain AS. This tag
stands for the peering business relationship between AS 2 and AS 1,
so that ASBR R2 of AS 1 can use it to determine which ASes Route A
can and cannot be distributed to prevent route leak (i.e.,
distributing Route A to the wrong AS). Suppose the destination AS of
the route A is AS4, then R2 will not distribute Route A to AS4 were
the export policies correctly configured.
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*************************
* *
Route A * AS1 *
---> * -----> Send A to AS3
+-----+ * +---+ +---+ * +-----+
... ---| AS2 |----|R1 |-----+---|R2 |-----| AS3 |--- ...
+-----+ * +---+\ +---+ * +-----+
* | \\ // |\ --X-- Not send A to AS4
* | \\// | \ * +-----+
. * | //\ | \----| AS4 |--- ...
* | // \\ | * +-----+
* | / \ | *
* +---+ +---+ *
. ---|R3 |---------|R4 | *
* +---+ +---+ *
* *
*************************
Figure 1: Routing between ISPs
2.2. Challenge of the Current Route Leak Prevention Methods
However, it could happen that the export policies configured at ASBRs
to prevent route leak are incorrect. Thus, when the route leak
prevnetion methods do not work, there requires a valid method to
detect any occurred leak in a timely manner so that the incorrect
policies/configurations can be modified to avoid further leak
affection.
3. Existing RLD Methods Discussion
There are some existing methods proposed for Route Leak Detection
(RLD).
Many attempts have been made to infer relationships and strategies
between ASs, however, the accuracy of these techniques is often
questioned. It's mainly due to the fact that the knowledge base for
inferring the AS relationships and their corresponding export
policies is limited to the routing information available at the data
collection points. In particular, the increase in the number of
Internet Exchange Points (IXPs) and their role in the recent
"flattening" of the Internet topology, makes that a large fraction of
AS relationships cannot be discovered using these data collection
points [Siddiqui].
Moreover, some other technologies extend existing routing protocols
to realize RLD. For example, modify the BGP update message, which
may bring about compatibility problems involved in the implementation
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of the solution. Beside, new extension brings interoperation, device
upgrade problems. Thus, extending the routing protocols to do RLD
should not be the first choice if there can be other options.
Considering the implementation details, different ISPs may have
concerns regarding security related data disclosure. Some BGP
monitoring tools, such as Looking Glass, not only require third-party
information to be collected in multiple favorable locations, but also
have limited knowledge of inter-domain routing status information
(some ISPs are reluctant to provide some information for
confidentiality reasons). This has led to the current BGP monitoring
tools not being well used by various ISPs. For this reason, a RLD
solution should try to avoid reliance on any third party ISP data
availability.
Summarizing the above discussions, we have identified the following
requirements when design a RLD solution:
Consideration 1: A route security protection scheme that a single
carrier can deploy.
Consideration 2: No changes required to control plane protocols
(e.g., BGP);
Consideration 3: No reliance on third party ISP information;
4. BMP Extension for RLD
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+--------+
| RLD |
| Server |
+--|-----+
|
*************|***********
* ISP A | *
* AS A1 | *
AS B1 * | * AS E1
+-------+ * +---+ | +---+ * +-------+
... ---| ISP B |----|R1 |-----+---|R2 |-----| ISP E |--- ...
+-------+ * +---+\ +---+ * +-------+
AS C1 * /| \\ // | * AS F1
+-------+ * / | \\// | * +-------+
... ---| ISP C |--- | //\ | /---| ISP F |--- ...
+-------+ * | // \\ | / * +-------+
AS D1 * | / \ | / * AS G1
+-------+ * +---+ +---+ * +-------+
... ---| ISP D |----|R3 |---------|R4 |-----| ISP G |--- ...
+-------+ * +---+ +---+ * +-------+
* *
*************************
Figure 2: RLD Server for One ISP
Considering the above mentioned factors, BMP is a good choice for
RLD, which has no dependency on third-party ISP, and no extension
required for routing protocols. Beside, by collecting information
using BMP from devices is not an RLD inferring method, which provides
true validation of ASes' peering business relationships.
We can use BMP (BGP Monitoring Protocol) to easily monitor BGP
routes, such as monitoring BGP Adj-RIB-In using the process defined
in [RFC7854], and monitoring BGP Adj-RIB-Out using the process
defined in [I-D.ietf-grow-bmp-adj-rib-out]. BMP is a management
plane protocol and a non-control plane protocol. Therefore, the use
of BMP does not impact the processing of BGP protocol, because BMP
can monitor the BGP protocol after the BGP protocol converges. This
document ...
5. Acknowledgements
TBD.
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6. IANA Considerations
TBD.
7. Security Considerations
TBD.
8. References
8.1. Normative References
[I-D.ietf-grow-bmp-adj-rib-out]
Evens, T., Bayraktar, S., Lucente, P., Mi, K., and S.
Zhuang, "Support for Adj-RIB-Out in BGP Monitoring
Protocol (BMP)", draft-ietf-grow-bmp-adj-rib-out-02 (work
in progress), September 2018.
[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>.
[RFC7908] Sriram, K., Montgomery, D., McPherson, D., Osterweil, E.,
and B. Dickson, "Problem Definition and Classification of
BGP Route Leaks", RFC 7908, DOI 10.17487/RFC7908, June
2016, <https://www.rfc-editor.org/info/rfc7908>.
8.2. Informative References
[Luckie] "AS Relationships, Customer Cones, and Validation",
October 2013.
[Siddiqui]
"Route Leak Detection Using Real-Time Analytics on local
BGP Information", 2014.
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Authors' Addresses
Yunan Gu
Huawei
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: guyunan@huawei.com
Shunwan Zhuang
Huawei
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: zhuangshunwan@huawei.com
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