Internet DRAFT - draft-ietf-ospf-encapsulation-cap
draft-ietf-ospf-encapsulation-cap
OSPF Working Group X. Xu, Ed.
Internet-Draft Huawei
Intended status: Standards Track B. Decraene, Ed.
Expires: April 12, 2018 Orange
R. Raszuk
Bloomberg LP
L. Contreras
Telefonica I+D
L. Jalil
Verizon
October 9, 2017
The Tunnel Encapsulations OSPF Router Information
draft-ietf-ospf-encapsulation-cap-09
Abstract
Networks use tunnels for a variety of reasons. A large variety of
tunnel types are defined and the tunnel encapsulator router needs to
select a type of tunnel which is supported by the tunnel decapsulator
router. This document defines how to advertise, in OSPF Router
Information Link State Advertisement (LSAs), the list of tunnel
encapsulations supported by the tunnel decapsulator.
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 12, 2018.
Xu, et al. Expires April 12, 2018 [Page 1]
Internet-Draft Tunnel Encapsulations RI October 2017
Copyright Notice
Copyright (c) 2017 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
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Tunnel Encapsulations TLV . . . . . . . . . . . . . . . . . . 3
4. Tunnel Sub-TLV . . . . . . . . . . . . . . . . . . . . . . . 3
5. Tunnel Parameter Sub-TLVs . . . . . . . . . . . . . . . . . . 4
5.1. Encapsulation Sub-TLV . . . . . . . . . . . . . . . . . . 5
5.2. Protocol Type Sub-TLV . . . . . . . . . . . . . . . . . . 5
5.3. Endpoint Sub-TLV . . . . . . . . . . . . . . . . . . . . 5
5.4. Color Sub-TLV . . . . . . . . . . . . . . . . . . . . . . 6
5.5. Load-Balancing Block Sub-TLV . . . . . . . . . . . . . . 6
5.6. IP QoS Field . . . . . . . . . . . . . . . . . . . . . . 6
5.7. UDP Destination Port . . . . . . . . . . . . . . . . . . 7
6. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7.1. OSPF Router Information . . . . . . . . . . . . . . . . . 7
7.2. Tunnel Parameter Sub-TLVs Registry . . . . . . . . . . . 7
8. Security Considerations . . . . . . . . . . . . . . . . . . . 8
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 9
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
11.1. Normative References . . . . . . . . . . . . . . . . . . 9
11.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
Networks use tunnels for a variety of reasons, such as:
o Partial deployment of IPv6 in IPv4 networks or IPv4 in IPv6
networks as described in [RFC5565], where IPvx tunnels are used
between IPvx-enabled routers so as to traverse non-IPvx routers.
Xu, et al. Expires April 12, 2018 [Page 2]
Internet-Draft Tunnel Encapsulations RI October 2017
o Remote Loop-Free Alternate (RLFA) repair tunnels as described in
[RFC7490], where tunnels are used between the Point of Local
Repair and the selected PQ node.
The tunnel encapsulator router needs to select a type of tunnel which
is supported by the tunnel decapsulator router. This document
defines how to advertise, in OSPF Router Information Link State
Advertisement (LSAs), the list of tunnel encapsulations supported by
the tunnel decapsulator. In this document, OSPF refers to both
OSPFv2 [RFC2328] and OSPFv3 [RFC5340].
2. Terminology
This memo makes use of the terms defined in [RFC7770].
3. Tunnel Encapsulations TLV
Routers advertise their supported tunnel encapsulation type(s) by
advertising a new TLV of the OSPF Router Information (RI) Opaque LSA
[RFC7770], referred to as the Tunnel Encapsulations TLV. This TLV is
applicable to both OSPFv2 and OSPFv3.
The Type code of the Tunnel Encapsulations is TBD1, the Length value
is variable, and the Value field contains one or more Tunnel Sub-TLVs
as defined in Section 4. Each Tunnel Sub-TLV indicates a particular
encapsulation format that the advertising router supports along with
the parameters corresponding to the tunnel type.
The Tunnel Encapsulations TLV MAY appear more than once within a
given OSPF Router Information (RI) Opaque LSA. If the Tunnel
Encapsulations TLV appears more than once in an OSPF Router
Information LSA, the set of all Tunnel Sub-TLVs from all Tunnel
Encapsulations TLV SHOULD be considered. The scope of the
advertisement depends on the application but it is recommended that
it SHOULD be domain-wide.
4. Tunnel Sub-TLV
The Tunnel Sub-TLV is structured as follows:
Xu, et al. Expires April 12, 2018 [Page 3]
Internet-Draft Tunnel Encapsulations RI October 2017
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tunnel Type (2 Octets) | Length (2 Octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Tunnel Parameter Sub-TLVs |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Tunnel Sub-TLV
Tunnel Type (2 octets): Identifies the type of tunneling
technology signaled. Tunnel types are shared with the BGP
extension [I-D.ietf-idr-tunnel-encaps] and hence are defined in
the IANA registry "BGP Tunnel Encapsulation Attribute Tunnel
Types". Unknown Tunnel types are to be ignored upon receipt.
Length (2 octets): Unsigned 16-bit integer indicating the total
number of octets of the value field.
Value (variable): Zero or more Tunnel Parameter Sub-TLVs as
defined in Section 5.
If a Tunnel Sub-TLV is invalid, it MUST be ignored and skipped.
However, other Tunnel Sub-TLVs MUST be considered
5. Tunnel Parameter Sub-TLVs
A Tunnel Parameter Sub-TLV is structured as follows:
+---------------------------------------------+
| Tunnel Parameter Sub-Type (2 Octets) |
+---------------------------------------------+
| Tunnel Parameter Length (2 Octets) |
+---------------------------------------------+
| Tunnel Parameter Value (Variable) |
| |
+---------------------------------------------+
Figure 2: Tunnel Parameter Sub-TLV
Tunnel Parameter Sub-Type (2 octets): Each sub-type defines a
parameter of the Tunnel Sub-TLV. Sub-Types are registered in the
IANA registry "OSPF Tunnel Parameter Sub-TLVs" Section 7.2.
Xu, et al. Expires April 12, 2018 [Page 4]
Internet-Draft Tunnel Encapsulations RI October 2017
Tunnel Parameter Length (2 octets): Unsigned 16-bit integer
indicating the total number of octets of the Tunnel Parameter
Value field.
Tunnel Parameter Value (variable): Encodings of the value field
depend on the Sub-TLV type as enumerated above. The following
sub-sections define the encoding in detail.
Any unknown Tunnel Parameter Sub-Type MUST be ignored and skipped
upon receipt. When a reserved value (See Section 7.2) is seen in an
LSA, it MUST be treated as an invalid Tunnel Parameter Sub-TLV. When
a Tunnel Parameter Value has an incorrect syntax or semantic, it MUST
be treated as an invalid Tunnel Parameter Sub-TLV. If a Tunnel
Parameter Sub-TLV is invalid, its Tunnel Sub-TLV MUST be ignored.
However, other Tunnel Sub-TLVs MUST be considered.
5.1. Encapsulation Sub-TLV
This Sub-TLV type is 1. The syntax, semantic, and usage of its value
field are defined in Section 3.2 "Encapsulation Sub-TLVs for
Particular Tunnel Types" of [I-D.ietf-idr-tunnel-encaps].
5.2. Protocol Type Sub-TLV
This Sub-TLV type is 2. The syntax, semantic, and usage of its value
field are defined in Section 3.4.1 "Protocol Type sub-TLV" of
[I-D.ietf-idr-tunnel-encaps].
5.3. Endpoint Sub-TLV
This Sub-TLV type is 3. It MUST be present once and only once in a
given Tunnel Sub-TLV. The value field contain two sub-fields:
a two-octet Address Family sub-field
an Address sub-field, whose length depends upon the Address
Family.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Family | Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
~ (Variable length) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Endpoint Sub-TLV
Xu, et al. Expires April 12, 2018 [Page 5]
Internet-Draft Tunnel Encapsulations RI October 2017
The Address Family subfield contains a value from IANA's "Address
Family Numbers" registry. In this document, we assume that the
Address Family is either IPv4 or IPv6; use of other address families
is outside the scope of this document.
If the Address Family subfield contains the value for IPv4, the
address subfield MUST contain an IPv4 address (a /32 IPv4 prefix).
In this case, the length field of Remote Endpoint sub-TLV MUST
contain the value 6.
If the Address Family subfield contains the value for IPv6, the
address sub-field MUST contain an IPv6 address (a /128 IPv6 prefix).
In this case, the length field of Remote Endpoint sub-TLV MUST
contain the value 18 (0x12). IPv6 link local addresses are not valid
values of the IP address field.
5.4. Color Sub-TLV
This Sub-TLV type is 4. It may appear zero or more time in a given
Tunnel Sub-TLV. The value field is a 4-octet opaque unsigned
integer.
The color value is user-defined and configured locally on the
advertising routers. It may be used by service providers to define
policies on the tunnel encapsulator routers, for example, to control
the selection of the tunnel to use.
This color value can be referenced by BGP routes carrying Color
Extended Community [I-D.ietf-idr-tunnel-encaps]. If the tunnel is
used to reach the BGP Next-Hop of BGP routes, then attaching a Color
Extended Community to those routes express the willingness of the BGP
speaker to use a tunnel of the same color.
5.5. Load-Balancing Block Sub-TLV
This Sub-TLV type is 5. The syntax, semantic, and usage of its value
field are defined in [RFC5640].
5.6. IP QoS Field
This Sub-TLV type is 6. The syntax, semantic, and usage of its value
field are defined in Section 3.3.1 "IPv4 DS Field" of
[I-D.ietf-idr-tunnel-encaps].
Xu, et al. Expires April 12, 2018 [Page 6]
Internet-Draft Tunnel Encapsulations RI October 2017
5.7. UDP Destination Port
This Sub-TLV type is 7. The syntax, semantic, and usage of its value
field are defined in Section 3.3.2 "UDP Destination Port" of
[I-D.ietf-idr-tunnel-encaps].
6. Operation
The advertisement of a Tunnel Encapsulations Sub-TLV indicates that
the advertising router supports a particular tunnel decapsulation
along with the parameters to be used for the tunnel. The decision to
use that tunnel is driven by the capability of the tunnel
encapsulator router to support the encapsulation type and the policy
on the tunnel encapsulator router. The Color Sub-TLV (See
Section 5.4) may be used as an input to this policy. Note that some
tunnel types may require the execution of an explicit tunnel setup
protocol before they can be used to transit data.
A tunnel MUST NOT be used if there is no route toward the IP address
specified in the Endpoint Sub-TLV (See Section 5.3) or if the route
is not advertised in the same OSPF domain.
7. IANA Considerations
7.1. OSPF Router Information
This document requests IANA to allocate a new code point from the
OSPF Router Information (RI) registry.
Value TLV Name Reference
----- ---------------------- -------------
TBD1 Tunnel Encapsulations This document
Figure 4: Tunnel Encapsulation Router Information
7.2. Tunnel Parameter Sub-TLVs Registry
This document requests IANA to create, under "Open Shortest Path
First (OSPF) Parameters", a new registry "OSPF Tunnel Parameter Sub-
TLVs" with the following registration procedure:
The values in the range 1-34999 are to be allocated using the
"Standards Action" registration procedure as defined in [RFC8126].
The values in the range 35000-65499 are to be allocated using the
"First Come, First Served" registration procedure.
Xu, et al. Expires April 12, 2018 [Page 7]
Internet-Draft Tunnel Encapsulations RI October 2017
Registry Name: OSPF Tunnel Parameter Sub-TLVs
Value Name Reference
----------- -------------------- ------------------------------
0 Reserved This document
1 Encapsulation This document
& [I-D.ietf-idr-tunnel-encaps]
2 Protocol Type This document
& [I-D.ietf-idr-tunnel-encaps]
3 Endpoint This document
4 Color This document
5 Load-Balancing Block This document & [RFC5640]
6 IP QoS This document
& [I-D.ietf-idr-tunnel-encaps]
7 UDP Destination Port This document
& [I-D.ietf-idr-tunnel-encaps]
8-65499 Unassigned
65500-65534 Experimental This document
65535 Reserved This document
Figure 5: OSPF Tunnel Parameter Sub-TLVs Registry
8. Security Considerations
Security considerations applicable to softwires can be found in the
mesh framework [RFC5565]. In general, security issues of the tunnel
protocols signaled through this OSPF capability extension are
inherited.
If a third-party is able to modify any of the information that is
used to form encapsulation headers, to choose a tunnel type, or to
choose a particular tunnel for a particular payload type, user data
packets may end up getting misrouted, mis-delivered, and/or dropped.
However, since an OSPF routing domain is usually a well-controlled
network under a single administrative domain, the possibility of the
above attack is very low.
We note that the last paragraph of Section 6 forbid the establishment
of a tunnel toward arbitrary destinations. It prohibits a
destination outside of the OSPF domain. This avoid that a third-
party gaining access to an OSPF router be able to send the traffic to
other destinations, e.g., for inspection purposes.
Security considerations for the base OSPF protocol are covered in
[RFC2328] and [RFC5340].
Xu, et al. Expires April 12, 2018 [Page 8]
Internet-Draft Tunnel Encapsulations RI October 2017
9. Contributors
Uma Chunduri
Huawei
Email: uma.chunduri@gmail.com
10. Acknowledgements
This document is partially inspired by [RFC5512].
The authors would like to thank Greg Mirsky, John E Drake, Carlos
Pignataro and Karsten Thomann for their valuable comments on this
document. Special thanks should be given to Acee Lindem for his
multiple detailed reviews of this document and help. The authors
would like to thank Pete Resnick, Joe Touch, David Mandelberg,
Sabrina Tanamal, Tim Wicinski, Amanda Baber for their Last Call
reviews and thank Spencer Dawkins, Mirja Kuehlewind, Ben Campbell,
Benoit Claise, Alvaro Retana, Adam Roach and Suresh Krishnan for
their AD reviews.
11. References
11.1. Normative References
[I-D.ietf-idr-tunnel-encaps]
Rosen, E., Patel, K., and G. Velde, "The BGP Tunnel
Encapsulation Attribute", draft-ietf-idr-tunnel-encaps-07
(work in progress), July 2017.
[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>.
[RFC5640] Filsfils, C., Mohapatra, P., and C. Pignataro, "Load-
Balancing for Mesh Softwires", RFC 5640,
DOI 10.17487/RFC5640, August 2009,
<https://www.rfc-editor.org/info/rfc5640>.
[RFC7770] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and
S. Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", RFC 7770, DOI 10.17487/RFC7770,
February 2016, <https://www.rfc-editor.org/info/rfc7770>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
Xu, et al. Expires April 12, 2018 [Page 9]
Internet-Draft Tunnel Encapsulations RI October 2017
11.2. Informative References
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328,
DOI 10.17487/RFC2328, April 1998,
<https://www.rfc-editor.org/info/rfc2328>.
[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
<https://www.rfc-editor.org/info/rfc5340>.
[RFC5512] Mohapatra, P. and E. Rosen, "The BGP Encapsulation
Subsequent Address Family Identifier (SAFI) and the BGP
Tunnel Encapsulation Attribute", RFC 5512,
DOI 10.17487/RFC5512, April 2009,
<https://www.rfc-editor.org/info/rfc5512>.
[RFC5565] Wu, J., Cui, Y., Metz, C., and E. Rosen, "Softwire Mesh
Framework", RFC 5565, DOI 10.17487/RFC5565, June 2009,
<https://www.rfc-editor.org/info/rfc5565>.
[RFC7490] Bryant, S., Filsfils, C., Previdi, S., Shand, M., and N.
So, "Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)",
RFC 7490, DOI 10.17487/RFC7490, April 2015,
<https://www.rfc-editor.org/info/rfc7490>.
Authors' Addresses
Xiaohu Xu (editor)
Huawei
Email: xuxiaohu@huawei.com
Bruno Decraene (editor)
Orange
Email: bruno.decraene@orange.com
Robert Raszuk
Bloomberg LP
Email: robert@raszuk.net
Xu, et al. Expires April 12, 2018 [Page 10]
Internet-Draft Tunnel Encapsulations RI October 2017
Luis M. Contreras
Telefonica I+D
Email: luismiguel.contrerasmurillo@telefonica.com
Luay Jalil
Verizon
Email: luay.jalil@verizon.com
Xu, et al. Expires April 12, 2018 [Page 11]
