Advertising Tunnel Encapsulation Capabilities in OSPF
draft-ietf-ospf-encapsulation-cap-07
The information below is for an old version of the document.
| Document | Type | Active Internet-Draft (ospf WG) | |
|---|---|---|---|
| Authors | Xiaohu Xu , Bruno Decraene , Robert Raszuk , Luis M. Contreras , Luay Jalil | ||
| Last updated | 2017-09-10 | ||
| Replaces | draft-xu-ospf-encapsulation-cap | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text xml htmlized pdfized bibtex | ||
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| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Acee Lindem | ||
| Shepherd write-up | Show Last changed 2017-05-19 | ||
| IESG | IESG state | IESG Evaluation::AD Followup | |
| Consensus boilerplate | Yes | ||
| Telechat date |
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| Responsible AD | Alia Atlas | ||
| Send notices to | Acee Lindem <acee@cisco.com> | ||
| IANA | IANA review state | Version Changed - Review Needed |
draft-ietf-ospf-encapsulation-cap-07
OSPF Working Group X. Xu, Ed.
Internet-Draft Huawei
Intended status: Standards Track B. Decraene, Ed.
Expires: March 14, 2018 Orange
R. Raszuk
Bloomberg LP
L. Contreras
Telefonica I+D
L. Jalil
Verizon
September 10, 2017
Advertising Tunnel Encapsulation Capabilities in OSPF
draft-ietf-ospf-encapsulation-cap-07
Abstract
Networks use tunnels for a variety of reasons. A large variety of
tunnel types are defined and the ingress tunnel router needs to
select a type of tunnel which is supported by the egress tunnel
router and itself. This document defines how to advertise the tunnel
encapsulation capabilities of egress tunnel routers in OSPF Router
Information Link State Advertisement (LSAs).
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), its areas, and its working groups. Note that other
groups may also distribute working documents as Internet-Drafts.
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/1id-abstracts.html
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html
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 March 14, 2018.
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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 Encapsulation Capabilities TLV . . . . . . . . . . . . 3
4. Tunnel Encapsulation Type Sub-TLVs . . . . . . . . . . . . . 3
5. Tunnel Encapsulation Attribute 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 . . . . . . . . . . . . . . . . . . . . . . 5
5.5. Load-Balancing Block Sub-TLV . . . . . . . . . . . . . . 6
5.6. IP QoS Field . . . . . . . . . . . . . . . . . . . . . . 6
5.7. UDP Destination Port . . . . . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6.1. OSPF Router Information . . . . . . . . . . . . . . . . . 6
6.2. Tunnel Encapsulation Attribute Sub-TLVs Registry . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . 7
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 7
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
10.1. Normative References . . . . . . . . . . . . . . . . . . 8
10.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
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.
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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 ingress tunnel router needs to select a type of tunnel which is
supported by the egress tunnel router and itself. This document
describes how to use OSPF Router Information Link State
Advertisements (LSAs) to advertise the tunneling capabilities of OSPF
routers acting as egress tunnel routers. 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 Encapsulation Capabilities TLV
Routers advertise their supported encapsulation type(s) by
advertising a new TLV of the OSPF Router Information (RI) Opaque LSA
[RFC7770], referred to as the Tunnel Encapsulation Capabilities TLV.
This TLV is applicable to both OSPFv2 and OSPFv3. The Tunnel
Encapsulation Capabilities TLV SHOULD NOT appear more than once
within a given OSPF Router Information (RI) Opaque LSA. If the
Tunnel Encapsulation Capabilities TLV appears more than once in an
OSPF Router Information LSA, only the first occurrence MUST be
processed and others SHOULD be ignored. The scope of the
advertisement depends on the application but it is recommended that
it SHOULD be domain-wide. The Type code of the Tunnel Encapsulation
Capabilities TLV is TBD1, the Length value is variable, and the Value
field contains one or more Tunnel Encapsulation Type Sub-TLVs (see
Section 4). Each Encapsulation Type Sub-TLVs indicates a particular
encapsulation format that the advertising router supports along with
the parameters to be used for the tunnel.
4. Tunnel Encapsulation Type Sub-TLVs
The Tunnel Encapsulation Type Sub-TLV is structured as follows:
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 Encapsulation Attribute Sub-TLVs |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Tunnel Type (2 octets): Identifies the type of tunneling
technology being 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 types are to be ignored and skipped upon receipt.
Length (2 octets): Unsigned 16-bit integer indicating the total
number of octets of the value field. Note that this is a padding
to be ignored if the length field is longer than the field
indicated by the sub-TLVs.
Value (variable): Zero or more Tunnel Encapsulation Attribute Sub-
TLVs as defined in Section 5.
5. Tunnel Encapsulation Attribute Sub-TLVs
Tunnel Encapsulation Attribute Sub-TLV are structured as follows:
+-----------------------------------+
| Sub-TLV Type (2 Octets) |
+-----------------------------------+
| Sub-TLV Length (2 Octets) |
+-----------------------------------+
| Sub-TLV Value (Variable) |
| |
+-----------------------------------+
Sub-TLV Type (2 octets): Each Sub-TLV type defines a certain
property of the tunnel TLV that contains this Sub-TLV. Types are
registered in the IANA registry "OSPF Tunnel Encapsulation
Attribute Sub-TLVs" Section 6.2.
Sub-TLV Length (2 octets): Unsigned 16-bit integer indicating the
total number of octets of the Sub-TLV value field.
Sub-TLV 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 Sub-TLVs MUST be deemed as invalid Sub-TLVs and therefore
MUST be ignored and skipped upon receipt. When a reserved value (See
Section 6.2) is seen in an LSA, it SHOULD be treated as an invalid
Sub-TLV. If a Sub-TLV is invalid, its Tunnel Encapsulation Type TLV
MUST be ignored and skipped. However, other Tunnel Encapsulation
Type TLVs MUST be considered.
The advertisement of an Encapsulation Type Sub-TLV (See Section 5.1)
indicates that the advertising router support a particular tunnel
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encapsulation along with the parameters to be used for the tunnel.
The decision to use that tunnel is driven by the capability of the
ingress router to support the encapsulation type and the policy on
the ingress 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 carry 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 by the router
advertising the Tunnel Encapsulation Attribute Sub-TLVs for the
tunnel.
5.1. Encapsulation Sub-TLV
This Sub-TLV of type 1 is defined in Section 3.2 "Encapsulation Sub-
TLVs for Particular Tunnel Types" of [I-D.ietf-idr-tunnel-encaps]
from both a syntax and semantic standpoint.
5.2. Protocol Type Sub-TLV
This Sub-TLV of type 2 is defined in Section 3.4.1 "Protocol Type
sub-TLV" of [I-D.ietf-idr-tunnel-encaps] from a syntactic, semantic,
and usage standpoint.
5.3. Endpoint Sub-TLV
Type is 3. The value field carries the Network Address to be used as
tunnel destination address.
If length is 4, the tunnel endpoint is an IPv4 address.
If length is 16, the tunnel endpoint is an IPv6 address.
5.4. Color Sub-TLV
Type is 4. 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 ingress tunnel 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 attached to those routes express the willingness
of the BGP speaker to use a tunnel of the same color.
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5.5. Load-Balancing Block Sub-TLV
This Sub-TLV of type 5 is defined in [RFC5640] from a syntactic,
semantic and usage standpoint.
5.6. IP QoS Field
This Sub-TLV of type 6 is defined in Section 3.3.1 "IPv4 DS Field" of
[I-D.ietf-idr-tunnel-encaps] from a syntactic, semantic and usage
standpoint.
5.7. UDP Destination Port
This Sub-TLV of type 7 is defined in Section 3.3.2 "UDP Destination
Port" of [I-D.ietf-idr-tunnel-encaps] from a syntactic, semantic and
usage standpoint.
6. IANA Considerations
6.1. 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 Encapsulation Capabilities This document
6.2. Tunnel Encapsulation Attribute Sub-TLVs Registry
This document requests IANA to create a new registry "Tunnel
Encapsulation Attribute Sub-TLVs" with the following registration
procedure:
The values in the range 1-255 are to be allocated using the
"Standards Action" registration procedure as defined in [RFC5226].
The values in the range 256-65499 are to be allocated using the
"First Come, First Served" registration procedure.
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Registry Name: OSPF Tunnel Encapsulation Attribute 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
7. 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, misdelivered, and/or dropped.
However, since an OSPF routing domain is usually well-controlled and
well-managed network, the possiblity of the above risk is very low.
Security considerations for the base OSPF protocol are covered in
[RFC2328] and [RFC5340].
8. Contributors
Uma Chunduri
Huawei
Email: uma.chunduri@gmail.com
9. 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,
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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.
10. References
10.1. 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>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<https://www.rfc-editor.org/info/rfc5226>.
[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>.
10.2. 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>.
Xu, et al. Expires March 14, 2018 [Page 8]
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[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
Luis M. Contreras
Telefonica I+D
Email: luismiguel.contrerasmurillo@telefonica.com
Luay Jalil
Verizon
Email: luay.jalil@verizon.com
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