AERO Minimal Encapsulation
draft-templin-aeromin-01
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Expired".
|
|
|---|---|---|---|
| Author | Fred Templin | ||
| Last updated | 2015-08-05 | ||
| RFC stream | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-templin-aeromin-01
Network Working Group F. Templin, Ed.
Internet-Draft Boeing Research & Technology
Intended status: Informational August 5, 2015
Expires: February 6, 2016
AERO Minimal Encapsulation
draft-templin-aeromin-01.txt
Abstract
Asymmetric Extended Route Optimization (AERO) specifies both a
control messaging and data packet forwarding facility for managing
tunnels over an enterprise network or other Internetwork. Although
AERO can operate with any tunnel encapsulation format, the base
document considers Generic UDP Encapsulation (GUE) as the default.
This document presents a minimal encapsulation format for AERO for
use when a UDP header is not needed.
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 February 6, 2016.
Copyright Notice
Copyright (c) 2015 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
(http://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
Templin Expires February 6, 2016 [Page 1]
Internet-Draft AERO Minimal Encapsulation August 2015
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Minimal Encapsulation Format . . . . . . . . . . . . . . . . 3
3. When to Insert the IPv6 Fragment Header . . . . . . . . . . . 3
4. Considerations for Using Minimal Encapsulation . . . . . . . 4
5. Minimal Encapsulation using GRE . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. Security Considerations . . . . . . . . . . . . . . . . . . . 5
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
9.1. Normative References . . . . . . . . . . . . . . . . . . 5
9.2. Informative References . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
Asymmetric Extended Route Optimization (AERO) [I-D.templin-aerolink]
specifies both a control messaging and data packet forwarding
facility for forwarding Internet Protocol (IP) packets [RFC0791]
[RFC2460] over an enterprise network or other Internetwork through a
process known as tunneling. Although AERO can operate with any
tunnel encapsulation format, the base document specifies the
insertion of a User Datagram Protocol (UDP) header [RFC0768] with
port 8060 between the inner and outer IP headers per the Generic UDP
Encapsulation (GUE) [I-D.ietf-nvo3-gue] specification. This document
presents a minimal encapsulation format for AERO for use when a UDP
header is not needed.
In its minimal form, AERO can use direct IP-in-IP encapsulation
[RFC2003][RFC2473][RFC4213] or Generic Routing Encapsulation (GRE)
[RFC2784][RFC2890] for interior routing and addressing services. The
encapsulation is therefore only differentiated from other tunnel
types through the application of AERO control messaging.
However, the tunnel fragmentation required by AERO to support a
guaranteed minimum 1500 bytes requires a different fragment header
than the one offered by GUE [I-D.herbert-gue-fragmentation] .
Instead, for simple IP-in-IP encapsulation an IPv6 fragment header is
inserted directly between the inner and outer IP headers when needed,
i.e., even if the outer header is IPv4. The IPv6 Fragment Header is
identified to the outer IP layer by its IP protocol number, and the
Next Header field in the IPv6 Fragment Header identifies the inner IP
header version.
Templin Expires February 6, 2016 [Page 2]
Internet-Draft AERO Minimal Encapsulation August 2015
2. Minimal Encapsulation Format
Figure 1 shows the AERO minimal encapsulation format before any
fragmentation is applied:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Outer IPv4 Header | | Outer IPv6 Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|IPv6 Fragment Header (optional)| |IPv6 Fragment Header (optional)|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Inner IP Header | | Inner IP Header | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
~ ~ ~ ~
~ Inner Packet Body ~ ~ Inner Packet Body ~
~ ~ ~ ~
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Minimal Encapsulation in IPv4 Minimal Encapsulation in IPv6
Figure 1: Minimal Encapsulation Format
3. When to Insert the IPv6 Fragment Header
The IPv6 Fragment Header is inserted whenever the AERO tunnel ingress
needs to apply fragmentation to accommodate packets no larger than
1500 bytes. Fragmentation is performed on the inner packet while
encapsulating each inner packet fragment in identical outer IP and
IPv6 Fragment Headers. Fragmentation therefore follows the same
procedure as for the case when a UDP header is included, which
follows the same procedure as for standard IPv6 fragmentation.
The IPv6 Fragment Header can also be inserted in order to include a
coherent Identification value with each packet, e.g., to aid in
Duplicate Packet Detection (DPD). In this way, networking devices
can cache the Identification values of recently-seen packets and use
the cached values to determine whether a newly-arrived packet is in
fact a duplicate.
Finally, the Identification value within each packet could provide a
rough indicator of packet reordering, e.g., in cases when the tunnel
egress wishes to discard packets that are grossly out of order.
Templin Expires February 6, 2016 [Page 3]
Internet-Draft AERO Minimal Encapsulation August 2015
4. Considerations for Using Minimal Encapsulation
Minimal encapsulation is preferred in environments where UDP
encapsulation would add unnecessary overhead. For example, certain
low-bandwidth wireless data links may benefit from an 8-byte-per-
packet overhead reduction. This is not likely to be a prime
consideration for many modern wireless data links nor for most modern
wired-line data links.
UDP encapsulation can traverse network paths that are inaccessible to
minimal encapsulation, e.g., for crossing Network Address Translators
(NATs). More and more, network middleboxes are also being configured
to discard packets that include anything other than a well-known IP
protocol such as UDP and TCP. It may therefore be necessary to
consider the potential for middlebox filtering before enabling
minimal encapsulation in a given environment.
Evidence seems to suggest that IPv6 fragmentation does not work along
all paths, since well-meaning network middleboxes may consider it as
an attack.
5. Minimal Encapsulation using GRE
GRE encapsulation can be used instead of simple IP-in-IP
encapsulation when GRE facilities such as keys and checksums are
desired. In that case, AERO can include a GRE fragmentation header
in the encpasulation [I-D.templin-intarea-grefrag] as shown in
Figure 2:
Templin Expires February 6, 2016 [Page 4]
Internet-Draft AERO Minimal Encapsulation August 2015
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Outer IP Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GRE Header |
| (with checksum, key, etc..) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GRE Framgent Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Inner IP Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ ~
~ Inner Packet Body ~
~ ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Minimal Encapsulation Using GRE
Figure 2: Minimal Encapsulation Using GRE
6. IANA Considerations
This document introduces no IANA considerations.
7. Security Considerations
Security considerations are discussed in the base AERO specification
[I-D.templin-aerolink].
8. Acknowledgements
TBD
9. References
9.1. Normative References
[RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
DOI 10.17487/RFC0768, August 1980,
<http://www.rfc-editor.org/info/rfc768>.
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
DOI 10.17487/RFC0791, September 1981,
<http://www.rfc-editor.org/info/rfc791>.
Templin Expires February 6, 2016 [Page 5]
Internet-Draft AERO Minimal Encapsulation August 2015
[RFC2003] Perkins, C., "IP Encapsulation within IP", RFC 2003,
DOI 10.17487/RFC2003, October 1996,
<http://www.rfc-editor.org/info/rfc2003>.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
December 1998, <http://www.rfc-editor.org/info/rfc2460>.
[RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in
IPv6 Specification", RFC 2473, DOI 10.17487/RFC2473,
December 1998, <http://www.rfc-editor.org/info/rfc2473>.
[RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P.
Traina, "Generic Routing Encapsulation (GRE)", RFC 2784,
DOI 10.17487/RFC2784, March 2000,
<http://www.rfc-editor.org/info/rfc2784>.
[RFC2890] Dommety, G., "Key and Sequence Number Extensions to GRE",
RFC 2890, DOI 10.17487/RFC2890, September 2000,
<http://www.rfc-editor.org/info/rfc2890>.
[RFC4213] Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms
for IPv6 Hosts and Routers", RFC 4213,
DOI 10.17487/RFC4213, October 2005,
<http://www.rfc-editor.org/info/rfc4213>.
9.2. Informative References
[I-D.herbert-gue-fragmentation]
Herbert, T. and F. Templin, "Fragmentation option for
Generic UDP Encapsulation", draft-herbert-gue-
fragmentation-00 (work in progress), March 2015.
[I-D.ietf-nvo3-gue]
Herbert, T., Yong, L., and O. Zia, "Generic UDP
Encapsulation", draft-ietf-nvo3-gue-01 (work in progress),
June 2015.
[I-D.templin-aerolink]
Templin, F., "Asymmetric Extended Route Optimization
(AERO)", draft-templin-aerolink-61 (work in progress),
August 2015.
[I-D.templin-intarea-grefrag]
Templin, F., "GRE Tunnel Fragmentation", draft-templin-
intarea-grefrag-00 (work in progress), April 2015.
Templin Expires February 6, 2016 [Page 6]
Internet-Draft AERO Minimal Encapsulation August 2015
Author's Address
Fred L. Templin (editor)
Boeing Research & Technology
P.O. Box 3707
Seattle, WA 98124
USA
Email: fltemplin@acm.org
Templin Expires February 6, 2016 [Page 7]