Network Working Group T. King
Internet-Draft D. Kopp
Intended status: Standards Track DE-CIX
Expires: October 12, 2017 A. Lambrianidis
AMS-IX
A. Fenioux
France-IX
April 10, 2017
Signaling Prefix Origin Validation Results from a Route Server to Peers
draft-ietf-sidrops-route-server-rpki-light-02
Abstract
This document defines the usage of the BGP Prefix Origin Validation
State Extended Community [RFC8097] to signal prefix origin validation
results from a route server to its peers. Upon reception of prefix
origin validation results peers can use this information in their
local routing decision process.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to
be interpreted as described in [RFC2119] only when they appear in all
upper case. They may also appear in lower or mixed case as English
words, without normative meaning.
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 http://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 October 12, 2017.
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Copyright Notice
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This document is subject to BCP 78 and the IETF Trust's Legal
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. BGP Prefix Origin Validation State Utilized at Route-Servers 3
3. Signaling Prefix Origin Validation Results from a Route
Server to Peers . . . . . . . . . . . . . . . . . . . . . . . 4
4. Operational Recommendations . . . . . . . . . . . . . . . . . 4
4.1. Local Routing Decision Process . . . . . . . . . . . . . 4
4.2. Route Server Receiving the BGP Prefix Origin Validation
State Extended Community . . . . . . . . . . . . . . . . 4
4.3. Information about Validity of a BGP Prefix Origin Not
Available at a Route-Server . . . . . . . . . . . . . . . 5
4.4. Error Handling at Peers . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.1. Normative References . . . . . . . . . . . . . . . . . . 6
7.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
RPKI-based prefix origin validation [RFC6480] can be a significant
operational burden for BGP peers to implement and adopt. In order to
boost acceptance and usage of prefix origin validation and ultimately
increase the security of the Internet routing system, IXPs may
provide RPKI-based prefix origin validation at the route server
[RFC7947]. The result of this prefix origin validation is signaled
to peers by using the BGP Prefix Origin Validation State Extended
Community as introduced in [RFC8097].
Peers receiving the prefix origin validation result from the route
server(s) can use this information in their local routing decision
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process for acceptance, rejection, preference, or other traffic
engineering purposes of a particular route.
2. BGP Prefix Origin Validation State Utilized at Route-Servers
A route server that is aware of a BGP Prefix Origin Validation state
for a certain route can handle this information in one of the
following modes of operation:
Simple Tagging: The prefix origin validation state is tagged to the
route as described in Section 3.
This mode of operation is like the tradional way route servers
work, however, the prefix origin validation state information is
additionally available for peers.
Dropping and Tagging: Routes for which the prefix origin validation
state is "invalid" (according to [RFC6811]) are dropped by the
route server. Routes which show a prefix origin validation state
of "not found" and "valid" (according to [RFC6811]) are tagged
accordingly to Section 3.
Security is higher rated than questionable reachability of a
prefix by this mode of operation.
Prioritizing and Tagging: If the route server learned for a
particular prefix more than one route it removes firstly the set
of "invalid" routes and secondly the "not found" routes unless
the set of routes is empty. Based on the set of routes left over
the BGP best path section algorithm is executed. The selected
route is marked accordinly to Section 3.
The BGP best path selection algorithm is changed by this mode of
operation in such a way that "valid" routes are preferred even if
they are unfavorable by the traditional best path selection
algorithm. This puts prefix origin validation on top of the best
path selection.
A route server MUST support the Simple Tagging mode of operation.
Other modes of operation are OPTIONAL. The mode of operation MAY be
configured by the route server operator for a route server instance
or for each BGP session with a peer seperately.
These mode of operations might be used in combination with [RFC7911]
in order to allow a peer to receive all routes and take the routing
decision by itself.
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3. Signaling Prefix Origin Validation Results from a Route Server to
Peers
The BGP Prefix Origin Validation State Extended Community (as defined
in [RFC8097]) is utilized for signaling prefix origin validation
result from a route server to peers.
[RFC8097] proposes an encoding of the prefix origin validation result
[RFC6811] as follows:
+-------+-----------------------------+
| Value | Meaning |
+-------+-----------------------------+
| 0 | Lookup result = "valid" |
| 1 | Lookup result = "not found" |
| 2 | Lookup result = "invalid" |
+-------+-----------------------------+
Table 1
This encoding is re-used. Route servers providing RPKI-based prefix
origin validation set the validation state according to the prefix
origin validation result (see [RFC6811]).
4. Operational Recommendations
4.1. Local Routing Decision Process
A peer receiving prefix origin validation results from the route
server MAY use the information in its own local routing decision
process. The local routing decision process SHOULD apply to the
rules as described in section 5 [RFC6811].
A peer receiving a prefix origin validation result from the route
server MAY redistribute this information within its own AS.
4.2. Route Server Receiving the BGP Prefix Origin Validation State
Extended Community
An IXP route server receiving routes from its peers containing the
BGP Prefix Origin Validation State Extended Community MUST remove the
extended community before the route is re-distributed to its peers.
This is required regardless of whether the route server is executing
prefix origin validation or not.
Failure to do so would allow opportunistic peers to advertise routes
tagged with arbitrary prefix origin validation results via a route
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server, influencing maliciously the decision process of other route
server peers.
4.3. Information about Validity of a BGP Prefix Origin Not Available at
a Route-Server
In case information about the validity of a BGP prefix origin is not
available at the route server (e.g., error in the ROA cache, CPU
overload) the route server MUST NOT add the BGP Prefix Origin
Validation State Extended Community to the route.
4.4. Error Handling at Peers
A route sent by a route server SHOULD only contain none or one BGP
Prefix Origin Validation State Extended Community.
A peer receiving a route from a route server containing more than one
BGP Prefix Origin Validation State Extended Community SHOULD only
consider the largest value (as described in Table 1) in the
validation result field and disregard the other values. Values
larger than two in the validation result field MUST be disregarded.
5. IANA Considerations
None.
6. Security Considerations
All security considerations described in RFC RFC6811 [RFC6811] fully
apply to this document.
Additionally, threat agents polluting ROA cache server(s) run by IXP
operators could cause significant operational impact, since multiple
route server clients could be affected. Peers should be vigilant as
to the integrity and authenticity of the origin validation results,
as they are provided by a third party, namely the IXP operator
hosting both the route server as well as any ROA cache server(s).
Therefore, a route server could be misused to spread malicious prefix
origin validation results. However, peers already trust the route
server for the collection, filtering (e.g. IRR database filtering),
and redistribution of BGP routing information to other peers. So, no
change in the trust level is needed for this proposal.
To facilitate trust and help with peers establishing appropriate
controls in mitigating the risks mentioned above, IXPs SHOULD provide
out-of-band means for peers to ensure that the ROA validation process
has not been compromised or corrupted.
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While beeing under DDoS attacks, it is a common practice for peers
connected to an IXP to make use of blackholing services (see
[RFC7999]). Peers are using blackholing to drop traffic, typically
by announcing a more specific prefix, which is under attack. A peer
SHOULD make sure that this prefix is covered by an appropriate ROA.
7. References
7.1. 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,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
Communities Attribute", RFC 4360, DOI 10.17487/RFC4360,
February 2006, <http://www.rfc-editor.org/info/rfc4360>.
[RFC6811] Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R.
Austein, "BGP Prefix Origin Validation", RFC 6811,
DOI 10.17487/RFC6811, January 2013,
<http://www.rfc-editor.org/info/rfc6811>.
[RFC7911] Walton, D., Retana, A., Chen, E., and J. Scudder,
"Advertisement of Multiple Paths in BGP", RFC 7911,
DOI 10.17487/RFC7911, July 2016,
<http://www.rfc-editor.org/info/rfc7911>.
[RFC8097] Mohapatra, P., Patel, K., Scudder, J., Ward, D., and R.
Bush, "BGP Prefix Origin Validation State Extended
Community", RFC 8097, DOI 10.17487/RFC8097, March 2017,
<http://www.rfc-editor.org/info/rfc8097>.
7.2. Informative References
[RFC6480] Lepinski, M. and S. Kent, "An Infrastructure to Support
Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480,
February 2012, <http://www.rfc-editor.org/info/rfc6480>.
[RFC7947] Jasinska, E., Hilliard, N., Raszuk, R., and N. Bakker,
"Internet Exchange BGP Route Server", RFC 7947,
DOI 10.17487/RFC7947, September 2016,
<http://www.rfc-editor.org/info/rfc7947>.
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[RFC7999] King, T., Dietzel, C., Snijders, J., Doering, G., and G.
Hankins, "BLACKHOLE Community", RFC 7999,
DOI 10.17487/RFC7999, October 2016,
<http://www.rfc-editor.org/info/rfc7999>.
Authors' Addresses
Thomas King
DE-CIX Management GmbH
Lichtstrasse 43i
Cologne 50825
DE
Email: thomas.king@de-cix.net
Daniel Kopp
DE-CIX Management GmbH
Lichtstrasse 43i
Cologne 50825
DE
Email: daniel.kopp@de-cix.net
Aristidis Lambrianidis
Amsterdam Internet Exchange
Frederiksplein 42
Amsterdam 1017 XN
NL
Email: aristidis.lambrianidis@ams-ix.net
Arnaud Fenioux
France-IX
88 Avenue Des Ternes
Paris 75017
FR
Email: afenioux@franceix.net
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