wdiff rfc4719.original rfc4719.txt

Network Working Group Rahul Aggarwal
Internet Draft R. Aggarwal, Ed.
Request for Comments: 4719 Juniper Networks
Expiration Date: February 2007 W. Mark Townsley
Maria A.
Category: Standards Track M. Townsley, Ed.
M. Dos Santos Santos, Ed.
Cisco Systems
Editors
August
November 2006

Transport of Ethernet Frames over L2TPv3

draft-ietf-l2tpext-pwe3-ethernet-09.txt
Layer 2 Tunneling Protocol Version 3 (L2TPv3)

Status of this This Memo

By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.

Internet-Drafts are working documents of

This document specifies an Internet standards track protocol for the
Internet Engineering
Task Force (IETF), its areas, community, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.

Internet-Drafts are draft documents valid requests discussion and suggestions for a maximum
improvements. Please refer to the current edition of six months the "Internet
Official Protocol Standards" (STD 1) for the standardization state
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."

The list status of current Internet-Drafts can be accessed at
http://www.ietf.org/1id-abstracts.html

The list this protocol. Distribution of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html this memo is unlimited.

Abstract

This document describes the transport of Ethernet frames over the
Layer 2 Tunneling Protocol (L2TPv3). This includes the transport of
Ethernet
port to port port-to-port frames as well as the transport of Ethernet
VLAN frames. The mechanism described in this document can be used in
the creation of Pseudo Wires Pseudowires to transport Ethernet frames over an IP
network.

Contributors

Following is the complete list of contributors to this document.

Rahul Aggarwal
Juniper Networks

Xipeng Xiao
Riverstone Networks

W. Mark Townsley
Stewart Bryant
Maria Alice Dos Santos
Cisco Systems

Cheng-Yin Lee
Alcatel

Tissa Senevirathne
Consultant

Mitsuru Higashiyama
Anritsu Corporation

Table of Contents

Status of this Memo.......................................... 1

1. Introduction.............................................. 3
1.1 Abbreviations......................................... 3
1.2 Introduction ....................................................2
1.1. Specification of Requirements ..............................2
1.2. Abbreviations ..............................................3
1.3. L2TPv3 Control Message Types.......................... 4
1.3 Requirements.......................................... 4 Types ...............................3
1.4. Requirements ...............................................3
2. PW Establishment.......................................... 5
2.1 Establishment ................................................4
2.1. LCCE-LCCE Control Connection Establishment............ 5
2.2 Establishment .................4
2.2. PW Session Establishment.............................. 5
2.3 Establishment ...................................4
2.3. PW Session Monitoring................................. 6 Monitoring ......................................6
3. Packet Processing......................................... 8
3.1 Encapsulation......................................... 8
3.2 Sequencing............................................ 8
3.3 Processing ...............................................7
3.1. Encapsulation .............................................7
3.2. Sequencing ................................................7
3.3. MTU Handling.......................................... 8 Handling ..............................................7
4. Applicability Statement................................... 9 Statement .........................................8
5. Congestion Control........................................ 11 Control .............................................10
6. Security Considerations................................... 12 Considerations ........................................10
7. IANA Considerations....................................... 12 Considerations ............................................11
8. Acknowledgements.......................................... 12 Contributors ...................................................11
9. References................................................ 12
9.1 Acknowledgements ...............................................11
10. References ....................................................12
10.1. Normative References.................................. 12
9.2 References .....................................12
10.2. Informative References................................ 13

10. Author Information....................................... 13

Specification of Requirements

In this document, several words are used to signify the requirements
of the specification. These words are often capitalized. 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 [RFC2119]. References ...................................12

1. Introduction

L2TPv3

The Layer 2 Tunneling Protocol, Version 3 (L2TPv3) can be used as a
control protocol and for data encapsulation to set up Pseudo Wires (PW) Pseudowires
(PWs) for transporting layer 2 Packet Data Units across an IP network
[RFC3931]. This document describes the transport of Ethernet frames
over L2TPv3 including the PW establishment and data encapsulation.

The term "Ethernet" in this draft document is used with the intention to
include all such protocols that are reasonably similar in their
packet format to IEEE 802.3 [802.3], including variants or extensions
which
that may or may not necessarily be sanctioned by the IEEE (including
such things frames as jumbo frames, etc). etc.). The term "VLAN" in this draft is
used with the intention document
is used with the intention to include all virtual LAN tagging
protocols such as IEEE 802.1Q [802.1Q], 802.1ad [802.1ad], etc.

1.1. Specification of Requirements

In this document, several words are used to signify the requirements
of the specification. These words are often capitalized. The key
words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
"SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document
are to include all virtual LAN tagging protocols
such be interpreted as IEEE 802.1Q [802.1Q], 802.1ad [802.1ad], etc.

1.1 described in [RFC2119].

1.2. Abbreviations

AC Attachment Circuit (See (see [RFC3985])
CE Customer Edge (Typically also the L2TPv3 Remote System)
LCCE L2TP Control Connection Endpoint (See (see [RFC3931])
NSP Native Service Processing (See (see [RFC3985])
PE Provider Edge (Typically also the LCCE) (See (see [RFC3985])
PSN Packet Switched Network (See (see [RFC3985])
PW Pseudo-Wire (See Pseudowire (see [RFC3985])
PWE3 Pseudo-Wire Pseudowire Emulation Edge to Edge (Working Group)

1.2

1.3. L2TPv3 Control Message Types

Relevant L2TPv3 control message types (See (see [RFC3931]) are listed for
reference.

SCCRQ L2TPv3 Start-Control-Connection-Request control message
SCCRP L2TPv3 Start-Control-Connection-Reply control message
SCCCN L2TPv3 Start-Control-Connection-Connected control message
STOPCCN
StopCCN L2TPv3 Stop-Control-Connection-Notification control message
ICRQ L2TPv3 Incoming-Call-Request control message
ICRP L2TPv3 Incoming-Call-Reply control message
ICCN L2TPv3 Incoming-Call-Connected control message
OCRQ L2TPv3 Outgoing-Call-Request control message
OCRP L2TPv3 Outgoing-Call-Reply control message
OCCN L2TPv3 Outgoing-Call-Connected control message
CDN L2TPv3 Call-Disconnect-Notify control message
SLI L2TPv3 Set-Link-Info control message

1.3

1.4. Requirements

An Ethernet PW emulates a single Ethernet link between exactly two
endpoints. The following figure depicts the PW termination relative
to the NSP and PSN tunnel within a an LCCE [RFC3985]. The Ethernet
interface may be connected to one or more Remote Systems (an L2TPv3
Remote System is referred to as Customer Edge (CE) in this and
associated PWE3 documents). The LCCE may or may not be a PE.

+---------------------------------------+
| LCCE |
+-+ +-----+ +------+ +------+ +-+
|P| | | |PW ter| | PSN | |P|
Ethernet <==>|h|<=>| NSP |<=>|minati|<=>|Tunnel|<=>|h|<==> PSN
Interface |y| | | |on | | | |y|
+-+ +-----+ +------+ +------+ +-+
| |
+---------------------------------------+
Figure 1: PW termination
The PW termination point receives untagged (also referred to as
'raw') or tagged Ethernet frames and delivers them unaltered to the
PW termination point on the remote LCCE. Hence Hence, it can provide
untagged or tagged Ethernet link emulation service.

The "NSP" function includes packet processing needed to translate the
Ethernet frames that arrive at the CE-LCCE interface to/from the
Ethernet frames that are applied to the PW termination point. Such
functions may include stripping, overwriting overwriting, or adding VLAN tags.
The NSP functionality can be used in conjunction with local
provisioning to provide heterogeneous services where the CE-LCCE
encapsulations at the two ends may be different.

The physical layer between the CE and LCCE, and any adaptation (NSP)
functions between it and the PW termination, are outside of the scope
of PWE3 and are not defined here.

2. PW Establishment

With L2TPv3 as the tunneling protocol, Ethernet PWs are L2TPv3
sessions. An L2TP control connection Control Connection has to be set up first between
the two LCCEs. Individual PWs can then be established as L2TP
sessions.

2.1

2.1. LCCE-LCCE Control Connection Establishment

The two LCCEs that wish to set up Ethernet PWs MUST establish a an L2TP
control connection
Control Connection first as described in [RFC3931]. Hence Hence, an
Ethernet PW type Type must be included in the Pseudo Wire Pseudowire Capabilities List
as defined in [RFC3931]. The type of PW can be either "Ethernet
port" or "Ethernet VLAN". This indicates that the control connection Control Connection
can support the establishment of Ethernet PWs. Note that there are
two Ethernet PW types Types required. For connecting an Ethernet port to
another Ethernet port, the PW Type MUST be "Ethernet port"; for
connecting an Ethernet VLAN to another Ethernet VLAN, the PW Type
MUST be "Ethernet VLAN".

2.2

2.2. PW Session Establishment

The provisioning of an Ethernet port or Ethernet VLAN and its
association with a PW triggers the establishment of an L2TP session
via the standard Incoming Call three-way handshake described in
Section 3.4.1 of [RFC3931].

Note that an L2TP Outgoing Call is essentially a method of
controlling the originating point of an SVC, a Switched Virtual Circuit
(SVC), allowing it to be established from any reachable L2TP-enabled
device able to perform outgoing calls. The Outgoing Call model and
its corresponding OCRQ,
OCRP OCRP, and OCCN control messages are mainly
used within the dial arena with L2TPv2 today and has not been found
applicable for PW applications yet.

The following are the signaling elements needed for the Ethernet PW
establishment:

a) Pseudo Wire Pseudowire Type: The type of a Pseudo Wire Pseudowire can be either "Ethernet
port" or "Ethernet VLAN". Each LCCE signals its Pseudo Wire Pseudowire type
in the Pseudowire Type AVP [RFC3931]. The assigned values for
"Ethernet port" and "Ethernet VLAN" Pseudo Wire Pseudowire types are captured
in the "IANA Considerations" of this document. The Pseudowire
Type AVP MUST be present in the ICRQ.

b) Pseudo Wire Pseudowire ID: Each PW is associated with a Pseudo Wire Pseudowire ID. The
two LCCEs of a PW have the same Pseudo Wire Pseudowire ID for it. The Remote
End Identifier AVP [RFC3931] is used to convey the Pseudo Wire Pseudowire ID.
The Remote End Identifier AVP MUST be present in the ICRQ in order
for the remote LCCE to determine the PW to associate the L2TP
session with. An implementation MUST support a Remote End
Identifier of four octets known to both LCCEs either by manual
configuration or some other means. Additional Remote End
Identifier formats which that MAY be supported are outside the scope of
this document.

c) The Circuit Status AVP [RFC3931] MUST be included in ICRQ and ICRP
to indicate the circuit status of the Ethernet port or Ethernet
VLAN. For ICRQ and ICRP, the Circuit Status AVP MUST indicate
that the circuit status is for a new circuit (refer to N bit in
Section 2.3.3). An Implementation implementation MAY send an ICRQ or ICRP before
an Ethernet interface is ACTIVE, as long as the Circuit Status AVP
(refer to A bit in Section 2.3.3) in the ICRQ or ICRP reflects the
correct status of the Ethernet port or Ethernet VLAN link. Subsequent A
subsequent circuit status change of the Ethernet port or Ethernet
VLAN MUST be conveyed in the Circuit Status AVP in ICCN or SLI
control messages. For ICCN and SLI (refer to Section 2.3.2), the
Circuit Status AVP MUST indicate that the circuit status is for an
existing circuit (refer to N bit in Section 2.3.3) and reflect the
current status of the link (refer to A bit in Section 2.3.3).

2.3

2.3. PW Session Monitoring

2.3.1. Control Connection Keep-alive

The working status of a PW is reflected by the state of the L2TPv3
session. If the corresponding L2TPv3 session is down, the PW
associated with it MUST be shut down. The control connection Control Connection keep-
alive mechanism of L2TPv3 can serve as a link status monitoring
mechanism for the set of PWs associated with a Control Connection.

2.3.2. SLI Message

In addition to the control connection Control Connection keep-alive mechanism of L2TPv3,
Ethernet PW over L2TP makes use of the Set Link Info Set-Link-Info (SLI) control
message defined in [RFC3931]. The SLI message is used to signal
Ethernet link status notifications between LCCEs. This can be useful
to indicate Ethernet interface state changes without bringing down
the L2TP session. Note that change in the Ethernet interface state
will trigger a an SLI message for each PW associated with that Ethernet
interface. This may be one Ethernet Port port PW or more than one
Ethernet VLAN PW. The SLI message MUST be sent any time there is a
status change of any values identified in the Circuit Status AVP.
The only exception to this is the initial ICRQ, ICRP ICRP, and CDN
messages
which that establish and teardown tear down the L2TP session itself. The
SLI message may be sent from either LCCE at any time after the first
ICRQ is sent (and perhaps before an ICRP is received, requiring the
peer to perform a reverse Session ID lookup).

2.3.3. Use of Circuit Status AVP for Ethernet

Ethernet PW reports Circuit Status circuit status with the Circuit Status AVP
defined in [RFC3931]. For reference, this AVP is shown below:

0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |N|A|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

The Value is a 16 bit 16-bit mask with the two least significant bits
defined and the remaining bits reserved for future use. Reserved
bits MUST be set to 0 when sending, sending and ignored upon receipt.

The A (Active) bit indicates whether the Ethernet interface is ACTIVE
(1) or INACTIVE (0).

The N (New) bit indicates whether the circuit status is for a new (1)
Ethernet circuit or an existing (0) Ethernet circuit.

3. Packet Processing

3.1

3.1. Encapsulation

The encapsulation described in this section refers to the
functionality performed by the PW termination point depicted in
figure
Figure 1, unless otherwise indicated.

The entire Ethernet frame, without the preamble or FCS, frame check
sequence (FCS), is encapsulated in L2TPv3 and is sent as a single
packet by the ingress LCCE. This is done regardless of whether an or
not a VLAN tag is present in the Ethernet frame or not. frame. For Ethernet port to port port-
to-port mode, the remote LCCE simply decapsulates the L2TP payload
and sends it out on the appropriate interface without modifying the
Ethernet header. For Ethernet VLAN to VLAN VLAN-to-VLAN mode, the remote LCCE MAY
rewrite the VLAN tag. As described in section Section 1, the VLAN tag
modification is an NSP function.

The Ethernet PW over L2TP is homogeneous with respect to packet
encapsulation i.e.
encapsulation, i.e., both the ends of the PW are either untagged or
tagged. The Ethernet PW can still be used to provide heterogeneous
services using NSP functionality at the ingress and/or egress LCCE.
The definition of such NSP functionality is outside the scope of this
document.

The maximum length of the Ethernet frame carried as the PWE PW payload is
irrelevant as far as the PWE PW is concerned. If anything, that value
would only be relevant when quantifying the faithfulness of the
emulation.

3.2

3.2. Sequencing

Data packet sequencing MAY be enabled for Ethernet PWs. The
sequencing mechanisms described in [RFC3931] MUST be used for
signaling sequencing support.

3.3

3.3. MTU Handling

With L2TPv3 as the tunneling protocol, the IP packet resulting from
the encapsulation is M + N bytes longer than the Ethernet frame
without the preamble or FCS. Here M is the length of the IP header
along with associated options and extension headers, and the value of
N depends on the following fields:

L2TP Session Header:
Flags, Ver, Res - 4 octets (L2TPv3 over UDP only)
Session ID - 4 octets
Cookie Size - 0, 4 4, or 8 octets
L2-Specific Sublayer - 0 or 4 octets (i.e., using sequencing)

Hence the range for N in octets is:
N = 4-16, for L2TPv3 data messages over IP;
N = 16-28, for L2TPv3 data messages over UDP;
(N does not include the IP header).

Fragmentation in the PSN can occur when using Ethernet over L2TP,
unless proper configuration and management of MTU sizes are in place
between the Customer Edge (CE) router, router and Provider Edge (PE) router,
and across the PSN. This is not specific only to Ethernet over
L2TPv3, and the base L2TPv3 specification [RFC3931] provides general
recommendations with respect to fragmentation and reassembly in
section
Section 4.1.4. "PWE3 Fragmentation and Reassembly" [L2TPFRAG] [RFC4623]
expounds on this topic further, topic, including a fragmentation and reassembly
mechanism within L2TP itself in the event that no other option is
available. Implementations MUST follow these guidelines with respect
to Fragmentation fragmentation and Reassembly. reassembly.

4. Applicability Statement

The Ethernet PW emulation allows a service provider to offer a "port
to port"
"port-to-port"-based Ethernet based service across an IP packet switched network
(PSN) Packet Switched
Network (PSN), while the Ethernet VLAN PW emulation allows an
"Ethernet VLAN
to VLAN" based VLAN-to-VLAN"-based Ethernet service across an IP packet switched network Packet
Switched Network (PSN).

The Ethernet or Ethernet VLAN PW emulation has the following
characteristics in relationship to the respective native service:

o Ethernet PW connects two Ethernet ACs while port ACs, and Ethernet VLAN PW
connects two Ethernet VLAN ACs, supporting which both support bi-directional
transport of variable length variable-length Ethernet frames. The ingress LCCE
strips the preamble and FCS from the Ethernet frame and transports
the frame in its entirety across the PW. This is done regardless
of the presence of the VLAN tag in the frame. The egress LCCE
receives the Ethernet frame from the PW and regenerates the
preamble and FCS before forwarding the frame to the attached
Remote System (See (see Section 3.1). Since FCS is not being
transported across either Ethernet or Ethernet VLAN PWs, payload
integrity transparency may be lost. To achieve payload integrity
transparency on Ethernet or Ethernet VLAN PWs using L2TP over IP
or L2TP over UDP/IP, the L2TPv3 session can utilize IPsec as
specified in Section 4.1.3 of [RFC3931].

o While architecturally [RFC3985] outside the scope of the L2TPv3 PW
itself, if VLAN tags are present, the NSP may rewrite VLAN tags on
ingress or egress from the PW (see section Section 3.1).

o The Ethernet or Ethernet VLAN PW only supports homogeneous
Ethernet frame type across the PW; both ends of the PW must be
either tagged or untagged. Heterogeneous frame type support
achieved with NSP functionality is outside the scope of this
document (See (see Section 3.1).

o Ethernet port or Ethernet VLAN status notification is provided
using the Circuit Status AVP in the SLI message (See Section 2.3.1). (see Sections
2.3.2 and 2.3.3). Loss of connectivity between LCCEs can be
detected by the L2TPv3 keep-alive mechanism (see Section 2.3.1 in of
this document and Section 4.4 of [RFC3931]). The LCCE can convey
these indications back to its attached Remote System.

o The maximum frame size that can be supported is limited by the PSN
MTU minus the L2TPv3 header size, unless fragmentation and
reassembly is used (see Section 3.3 of this document and Section
4.1.4 of [RFC3931]).

o The packet switched network Packet Switched Network may reorder, duplicate, or silently
drop packets. Sequencing may be enabled in the Ethernet or
Ethernet VLAN PW for some or all packets to detect lost,
duplicate, or out-of-order packets on a per-session basis (see
Section 3.2).

o The faithfulness of an Ethernet or Ethernet VLAN PW may be
increased by leveraging Quality of Service Quality-of-Service (QoS) features of the
LCCEs and the underlying PSN. For example example, for Ethernet 802.1Q
[802.1Q] VLAN transport, the ingress LCCE MAY consider the user
priority field (i.e. 802.1P) (i.e., 802.1p) of the VLAN tag for traffic
classification and QoS treatments, such as determining the DS
Differentiated Services (DS) field [RFC2474] of the encapsulating
IP header. Similarly, the egress LCCE MAY consider the DS field
of the encapsulating IP header when rewriting the user priority
field of the VLAN tag or queuing the Ethernet frame before
forwarding the frame to the Remote System. The mapping between
the user priority field and the IP header DS field as well as the Quality of Service
Quality-of-Service model deployed are application specific and are
outside the scope of this document.

5. Congestion Control

As explained in [RFC3985], the PSN carrying the PW may be subject to
congestion, with congestion characteristics depending on PSN type,
network architecture, configuration, and loading. During congestion congestion,
the PSN may exhibit packet loss that will impact the service carried
by the Ethernet or Ethernet VLAN PW. In addition, since Ethernet or
Ethernet VLAN PWs carry a variety of services across the PSN,
including but not restricted to TCP/IP, they may or may not behave in
a TCP-friendly manner prescribed by [RFC2914] and thus consume more
than their fair share.

Whenever possible, Ethernet or Ethernet VLAN PWs should be run over
traffic-engineered PSNs providing bandwidth allocation and admission
control mechanisms. IntServ-enabled domains providing the Guaranteed
Service (GS) or DiffServ-enabled domains using EF (expedited
forwarding) are examples of traffic-engineered PSNs. Such PSNs will
minimize loss and delay while providing some degree of isolation of
the Ethernet or Ethernet VLAN PW's effects from neighboring streams.

LCCEs SHOULD monitor for congestion (by using explicit congestion
notification,
notification or by measuring packet loss) in order to ensure that the
service using the Ethernet or Ethernet VLAN PW may be maintained.
When severe congestion is detected (for example example, when enabling
Sequencing
sequencing and detecting that the packet loss is higher than a
threshold)
threshold), the Ethernet or Ethernet VLAN PW SHOULD be halted by
tearing down the L2TP session via a CDN message. The PW may be
restarted by manual intervention, intervention or by automatic means after an
appropriate waiting time. Note that the thresholds and time periods
for shutdown and possible automatic recovery need to be carefully
configured. This is necessary to avoid loss of service due to
temporary congestion, congestion and to prevent oscillation between the congested
and halted states.

This specification offers no congestion control and is not TCP
friendly [TFRC]. Future works for PW congestion control (being
studied by the PWE3 Working Group) will provide congestion control
for all PW types including Ethernet and Ethernet VLAN PWs.

6. Security Considerations

Ethernet over L2TPv3 is subject to all of the general security
considerations outlined in [RFC3931].

7. IANA Considerations

The signaling mechanisms defined in this document rely upon the
allocation of
following Ethernet Pseudowire Types (see Pseudo Wire Pseudowire Capabilities List
as defined in 5.4.3 of [RFC3931] and L2TPv3 Pseudowire Types in 10.6
of [RFC3931]) [RFC3931]), which were allocated by the IANA (number space created
as part of publication of [RFC3931]):

Pseudowire Types
----------------
0x0004 Ethernet VLAN Pseudowire Type
0x0005 Ethernet Pseudowire Type

8. Contributors

The following is the complete list of contributors to this document.

Rahul Aggarwal
Juniper Networks

Xipeng Xiao
Riverstone Networks

W. Mark Townsley
Stewart Bryant
Maria Alice Dos Santos
Cisco Systems

Cheng-Yin Lee
Alcatel

Tissa Senevirathne
Consultant

Mitsuru Higashiyama
Anritsu Corporation

9. Acknowledgements

This draft evolves RFC evolved from the draft, document, "Ethernet Pseudo Wire Emulation
Edge-to-Edge". We would like to thank its authors, T.So, X.Xiao, L.
Anderson, C. Flores, N. Tingle, S. Khandekar, D. Zelig and G. Heron
for their contribution. We would also like to thank S. Nanji, the
author of the draft, "Ethernet Service for Layer Two Tunneling Protocol", for
writing the first Ethernet over L2TP draft. document.

Thanks to Carlos Pignataro for providing a thorough review and
helpful input.

10. References

9.1

10.1. Normative References

[RFC3931] J. Lau, M. J., Townsley, M., and I. Goyret, "Layer Two Tunneling
Protocol (Version 3)", RFC3931, - Version 3 (L2TPv3)", RFC 3931, March 2005.

[RFC2119] S. Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.

[L2TPFRAG] A.

[RFC4623] Malis, A. and M. Townsley, "PWE3 "Pseudowire Emulation Edge-to-
Edge (PWE3) Fragmentation and Reassembly", draft-ietf-pwe3-fragmentation-10.txt

9.2 RFC 4623,
August 2006.

10.2. Informative References

[RFC3985] S. Bryant, S. and P. Pate, "Pseudo Wire Emulation Edge-to-Edge Edge-to-
Edge (PWE3) Architecture", RFC3985, RFC 3985, March 2005 2005.

[RFC2914] S. Floyd, S., "Congestion Control Principles", BCP 41, RFC
2914, September 2000.

[RFC2474] K. Nichols, S. K., Blake, F. S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC2474, RFC 2474, December 1998
1998.

[802.3] IEEE, "IEEE std 802.3 -2005/Cor 1-2006 IEEE Standard for
Information Technology - Telecommuincations and
Information Exchange Between Systems - Local and
Metropolitan Area Networks", IEEE Std 802.3-2005/Cor
1-2006 (Corrigendum to IEEE Std 802.3-2005)

[802.1Q] IEEE, "IEEE standard for local and metropolitan area
networks virtual bridged local area networks", IEEE Std
802.1Q-2005 (Incorporates IEEE Std 802.1Q1998, IEEE Std
802.1u-2001, IEEE Std 802.1v-2001, and IEEE Std
802.1s-2002) 802.1s-
2002)

[802.1ad] IEEE, "IEEE Std 802.1ad - 2005 IEEE Standard for Local and
metropolitan area networks - virtual Bridged Local Area
Networks, Amendment 4: Provider Bridges", IEEE Std
802.1ad-2005 (Amendment to IEEE Std 8021Q-2005)

[TFRC] M. Handley, S. M., Floyd, J. S., Padhye, J., and J. Widmer, "TCP
Friendly Rate Control (TFRC): Protocol Specification",
RFC3448, RFC
3448, January 2003

10. 2003.

Author Information

Rahul Aggarwal
Juniper Networks
1194 North Mathilda Avenue
Sunnyvale, CA 94089
e-mail:

EMail: rahul@juniper.net

W. Mark Townsley
Cisco Systems
7025 Kit Creek Road
PO Box 14987
Research Triangle Park, NC 27709
e-mail:

EMail: mark@townsley.net

Maria Alice Dos Santos
Cisco Systems
170 W Tasman Dr
San Jose, CA 95134
e-mail:

EMail: mariados@cisco.com

Full Copyright Statement

This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.

This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST,
AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT
THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY
IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE.

Intellectual Property Statement

The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.

Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.

The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.

Disclaimer of Validity

This document and the information contained herein are provided on
an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE
INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.

Acknowledgment

Acknowledgement

Funding for the RFC Editor function is currently provided by the
Internet Society.