Encapsulating IP in UDP
draft-xu-softwire-ip-in-udp-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".
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|
|---|---|---|---|
| Authors | Xiaohu Xu , Lucy Yong , Yiu Lee , Fan Yongbing | ||
| Last updated | 2013-02-19 | ||
| RFC stream | (None) | ||
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| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
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| IESG | IESG state | I-D Exists | |
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draft-xu-softwire-ip-in-udp-01
Network Working Group X. Xu
Internet Draft L. Yong
Category: Standard Track Huawei
Y. Lee
Comcast
Y. Fan
China Telecom
Expires: August 2013 February 18, 2013
Encapsulating IP in UDP
draft-xu-softwire-ip-in-udp-01
Abstract
Existing Softwire encapsulation technologies are not adequate for
efficient load balancing of Softwire service traffic across IP
networks. This document specifies additional Softwire encapsulation
technology, referred to as IP-in-User Datagram Protocol (UDP), which
can facilitate the load balancing of Softwire service traffic across
IP networks.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on August 18, 2013.
Copyright Notice
Copyright (c) 2013 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
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Conventions used in this document
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].
Table of Contents
1. Introduction ................................................ 3
2. Terminology ................................................. 3
3. Encapsulation in UDP......................................... 3
4. Processing Procedures ....................................... 4
5. Security Considerations ..................................... 5
6. IANA Considerations ......................................... 5
7. Acknowledgements ............................................ 5
8. References .................................................. 5
8.1. Normative References ................................... 5
8.2. Informative References ................................. 6
Authors' Addresses ............................................. 6
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1. Introduction
To fully utilize the bandwidth available in IP networks and/or
facilitate recovery from a link or node failure, load balancing of
traffic over Equal Cost Multi-Path (ECMP) and/or Link Aggregation
Group (LAG) across IP networks is widely used. In practice, most
existing core routers in IP networks support distributing IP traffic
flows over ECMP paths and/or LAG based on the hash of the five-tuple
of User Datagram Protocol (UDP)[RFC768] and Transmission Control
Protocol (TCP) packets (i.e., source IP address, destination IP
address, source port, destination port, and protocol).
[RFC5640] describes a method for improving the load balancing
efficiency in a network carrying Softwire Mesh service [RFC5565]
over Layer Two Tunneling Protocol - Version 3 (L2TPv3) [RFC3931] and
Generic Routing Encapsulation (GRE)[RFC2784] encapsulations. However,
this method requires core routers to perform hash calculation on the
"load-balancing" field contained in tunnel encapsulation headers
(i.e., the Session ID field in L2TPv3 headers or the Key field in
GRE headers), which is not widely supported by existing core routers.
Since most existing core routers already support balancing IP
traffic flows based on the hash of the five-tuple of UDP packets, by
encapsulating Softwire service traffic into UDP tunnels, it will
enable existing core routers to perform efficient load-balancing of
the Softwire service traffic without requiring any change to them.
Therefore, this specification defines an IP-in-UDP encapsulation
method for Softwire service.
2. Terminology
This memo makes use of the terms defined in [RFC5565].
3. Encapsulation in UDP
IP-in-UDP encapsulation format is shown as follows:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Port = entropy | Dest Port = IP |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ IP Packet ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Source Port of UDP
This field contains an entropy value that is generated
by the ingress PE router. For example, the entropy value
can be generated by performing hash calculation on
certain fields in the customer packets (e.g., the five
tuple of UDP/TCP packets).
Destination Port of UDP
This field is set to a value (TBD) indicating the
encapsulated payload in the UDP header is an IP packet.
As for whether the encapsulated IP packet is IPv4 or
IPv6, it would be determined according to the Version
field in the IP header of the encapsulated IP packet.
UDP Length
The usage of this field is in accordance with the
current UDP specification [RFC768].
UDP Checksum
The usage of this field is in accordance with the
current UDP specification. To simplify the operation on
egress PE routers, this field is recommended to be set
to zero.
4. Processing Procedures
This IP-in-UDP encapsulation causes E-IP [RFC5565] packets to be
forwarded across an I-IP transit core via "UDP tunnels". When
performing IP-in-UDP encapsulation by an ingress AFBR, the entropy
value would be generated by the ingress PE router and then be filled
in the Source Port field of the UDP header.
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Transit routers, upon receiving these UDP encapsulated packets,
could balance these packets based on the hash of the five-tuple of
UDP packets.
Egress AFBRs receiving these UDP encapsulated packets MUST
decapsulate these packets by removing the UDP header and then
forward them accordingly.
5. Encapsulation Considerations
Similar to all other Softwire tunneling technologies, IP-in-UDP
encapsualtion introduces overheads and reduces the effective Maximum
Transmision Unit (MTU) size. IP-in-UDP encapsulation may also impact
Time-to-Live (TTL) and Differentiated Services (DSCP). Hence, IP-in-
UDP MUST follow the corresponding procedures defined in [RFC2003].
If an ingress AFBR performs fragmentation on an E-IP packet before
encapsulating, it MUST use the same source UDP port for all
fragmented packets so as to ensures these fragmented packets are
always forwarded on the same path.
5. Security Considerations
The security consideration for IP-in-UDP encapsulation format is the
same as that for the existing Softwire encapsulation methods for
Softwire service such as IP-in-IP.
6. IANA Considerations
A new UDP destination port number which indicates the encapsulated
payload following the UDP header is an IP packet needs to be
assigned by IANA.
7. Acknowledgements
Thanks to Vivek Kumar, Carlos Pignataro and Mark Townsley for their
valuable comments on the initial idea of this draft. Thanks to
Andrew G. Malis for his valuable comments on this draft.
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
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8.2. Informative References
[RFC2003] Perkins, C., "IP Encapsulation within IP", RFC 2003,
October 1996.
[RFC4213] Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms
for IPv6 Hosts and Routers", RFC 4213, October 2005.
[RFC5565] Wu, J., Cui, Y., Metz, C. and E. Rosen, "Softwire Mesh
Framework", RFC 5565, June 2009.
[RFC5640] Filsfils, C., Mohapatra, P., and C. Pignataro, "Load-
Balancing for Mesh Softwires", RFC 5640, August 2009.
[RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P.
Traina, "Generic Routing Encapsulation (GRE)", RFC 2784,
March 2000.
[RFC3931] Lau, J., Townsley, M., and I. Goyret, "Layer Two Tunneling
Protocol - Version 3 (L2TPv3)", RFC 3931, March 2005.
[RFC768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
August 1980.
[I-D.ietf-6man-udpchecksums] Eubanks, M., Chimento, P., and M.
Westerlund, "UDP Checksums for Tunneled Packets",
draft-ietf-6man-udpchecksums-04 (work in progress),
September 2012.
[I-D.ietf-6man-udpzero] Fairhurst, G. and M. Westerlund,
"Applicability Statement for the use of IPv6 UDP Datagrams
with Zero Checksums", draft-ietf-6man-udpzero-07 (work in
progress), October 2012.
[MPLS-in-UDP] Xu, X., Sheth, N., Yong, L., Pignataro, C., Fan, Y and
Z. Li, "Encapsulating MPLS in UDP", draft-ietf-mpls-in-
udp-00.txt (work in progress), January 2013.
Authors' Addresses
Xiaohu Xu
Huawei Technologies,
Beijing, China
Phone: +86-10-60610041
Email: xuxiaohu@huawei.com
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Lucy Yong
Huawei USA
5340 Legacy Dr.
Plano TX75025
Phone: 469-277-5837
Email: Lucy.yong@huawei.com
Yiu Lee
Comcast
One Comcast Center
Philadelphia, PA 1903
USA
Email: Yiu_Lee@Cable.Comcast.com
Yongbing Fan
China Telecom
Guangzhou, China.
Phone: +86 20 38639121
Email: fanyb@gsta.com