Internet Draft XiPeng Xiao
Document: draft-ietf-pwe3-requirements-01.txt Photuris Inc.
Expires: January 2002 Danny McPherson
Amber Networks
Prayson Pate
Overture Networks, Inc.
Craig White
Level 3 Communications, LLC.
Kireeti Kompella
Juniper Networks, Inc.
Vijay Gill
Metromedia Fiber Network, Inc.
Thomas D. Nadeau
Cisco Systems, Inc.
Requirements for Pseudo-Wre Emulation Edge-to-Edge (PWE3)
draft-ietf-pwe3-requirements-01.txt
Status of this Memo
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all provisions of Section 10 of RFC 2026. Internet-Drafts are
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Abstract
This document describes generic requirements for Pseudo-Wire
Emulation Edge to Edge (PWE3). It provides guidelines for other
working group documents that will define mechanisms for providing
pseudo-wire emulation of specific services such as Ethernet, ATM,
Frame Relay, TDM, and MPLS. It should be noted that the PWE3 Working
Group (PWE3 WG) standardizes mechanisms that can be used to provide
PWE3 services, but not the services themselves.
Internet Draft draft-ietf-pwe3-requirements-01 July, 2001
Copyright Notice
Copyright (C) The Internet Society (2001). All Rights Reserved.
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Table of Contents
1 Introduction ................................................. 4
1.1 Reference Model of PWE3 .................................... 4
1.2 Terminology ................................................ 5
2 PDU Encapsulation ............................................ 6
2.1 Conveyance of Necessary L2/L1 Header Information ........... 7
2.2 PDU Length ................................................. 7
2.3 Encapsulation of Control Messages of the Native Services
........................................................... 7
2.4 Support for Circuit Multiplexing ........................... 7
2.5 Packet Ordering ............................................ 7
2.6 Packet Duplication ......................................... 7
3 Carrying the PW PDUs over a Packet-Switched Network .......... 8
3.1 Setup of Pseudo-Wires ...................................... 8
3.2 Pseudo-Wire MTU ............................................ 8
3.3 Carrying Control Messages of the Native Services ........... 8
3.4 PSN Tunnel Header Overhead ................................. 9
4 Faithfulness of Emulated Services ............................ 9
4.1 Characteristics of an Emulated Service ..................... 9
4.2 Service Quality of Emulated Services ....................... 10
5 Maintenance of Emulated Services ............................. 10
5.1 Keep-alive ................................................. 10
5.2 Status Monitoring .......................................... 10
5.3 Notification of Status Changes ............................. 11
5.3.1 Up/Down Notification ..................................... 11
5.3.2 Misconnection and Payload Mistype ........................ 11
5.3.3 Packet Loss, Corruption, and Out-of-order Delivery ....... 11
5.3.4 Other Status Notification ................................ 11
5.3.5 Collective Status Notification ........................... 11
5.4 Clock Recovery ............................................. 12
6 Management of Emulated Services .............................. 12
6.1 MIBs ....................................................... 12
6.2 General MIB Requirements ................................... 12
6.3 Configuration and Provisioning ............................. 13
6.4 Performance Monitoring ..................................... 13
6.5 Fault Management and Notifications ......................... 13
6.6 Pseudo-Wire Traceroute ..................................... 13
7 Scalability .................................................. 13
8 Other Generic Requirements ................................... 14
8.1 RFC 2914 Conformance ....................................... 14
9 Non-Requirements ............................................. 14
10 Quality of Service (QoS) Considerations ..................... 15
11 Inter-domain Pseudo-Wires ................................... 15
12 Security Considerations ..................................... 15
12.1 Security Considerations for the Signaling/Control
Channel ................................................... 15
12.2 Security Considerations for the PW PDUs ................... 15
13 Deployment Considerations ................................... 16
14 Acknowledgments ............................................. 16
15 References .................................................. 16
16 Authors' Addresses .......................................... 17
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17 Full Copyright Section ...................................... 19
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1. Introduction
1.1. Reference Model of PWE3
To provide pseudo-wire emulation (PWE), two pseudo-wire end-services
(PWESs) of the same type are first configured between each customer
edge (CE) device and the corresponding provider edge (PE) device (See
Figure 1). A PWES is either:
- an Ethernet link or a VLAN link between two ports, or
- an ATM VC or VP, or
- a Frame Relay VC, or
- a TDM circuit, or
- an MPLS LSP.
A connection is then set up between the two PEs to connect these two
PWESs. This connection is called a pseudo-wire (PW) in the PWE3
context. During the setup of a PW, the two PEs will be configured or
will automatically exchange information about the service to be
emulated so that later they know how to process packets coming from
the other end. After the PW is set up, layer-2 (e.g. Ethernet, ATM,
Frame Relay and MPLS) or layer-1 (e.g. SONET/SDH) PDUs from a PWES
are encapsulated at the PW ingress. The encapsulated PDUs are then
sent over the PW to the egress, where L2 or L1 headers are re-
constructed and the resulted frames are forwarded in their native
format to the other CE.
|<------- Pseudo Wire ------>|
| |
| |<-- PSN Tunnel -->| |
PW V V V V PW
End Service+----+ +----+ End Service
+-----+ | | PE1|==================| PE2| | +-----+
| |----------|............PW1.............|----------| |
| CE1 | | | | | | | | CE2 |
| |----------|............PW2.............|----------| |
+-----+ | | |==================| | | +-----+
^ +----+ +----+ | ^
| Provider Edge 1 Provider Edge 2 |
| |
|<-------------- Emulated Service ---------------->|
Customer Customer
Edge 1 Edge 2
Figure 1: PWE3 Reference Model
This document does not assume that a particular type of PWs is used.
Instead, it describes generic requirements that apply to all PWs, for
all services including Ethernet, ATM, Frame Relay, TDM and MPLS.
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This document is not an introductory document. For an architecture
overview of PWE3, readers should refer to the PWE3 framework document
[PATE].
1.2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALLNOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119.
Below are the definitions for the terms used throughout the document.
Packet Switched Network
A Packet Switched Network (PSN) is a network
using IP, MPLS or L2TP as the unit of
switching.
Pseudo Wire Emulation Edge to Edge
Pseudo Wire Emulation Edge to Edge (PWE3) is a
mechanism that emulates the essential
attributes of a service (such as a T1 leased
line or Frame Relay) over a PSN.
Customer Edge A Customer Edge (CE) is a device where one end
of an emulated service originates and
terminates. The CE is not aware that it is
using an emulated service rather than a "real"
service.
Provider Edge A Provider Edge (PE) is a device that provides
PWE3 to a CE.
Pseudo Wire A Pseudo Wire (PW) is a connection between two
PEs carried over a PSN. The PE provides the
adaptation between the CE and the PW.
Pseudo Wire PDU A Pseudo Wire PDU (PW PDU) is a PDU sent on the
PW that contains all of the data and control
information necessary to provide the desired
service.
PSN Tunnel A PSN Tunnel is a tunnel inside which multiple
PWs can be nested so that they are transparent
to core network devices.
Path-oriented PW A Path-oriented PW is a PW for which the
network devices of the underlying PSN must
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maintain state information.
Non-path-oriented PW A Non-path-oriented PW is a PW for which the
network devices of the underlying PSN need not
maintain state information.
Service Interworking In Service Interworking, the IWF (Interworking
Function) between two dissimilar protocols
(e.g., ATM & MPLS, Frame Relay & ATM, ATM & IP,
ATM & L2TP, etc.) terminates the protocol used
in one network and translates (i.e. maps) its
Protocol Control Information (PCI) to the PCI
of the protocol used in other network for User,
Control and Management Plane functions to the
extent possible. In general, since not all
functions may be supported in one or other of
the networks, the translation of PCI may be
partial or non-existent. However, this should
not result in any loss of user data since the
payload is not affected by PCI conversion at
the service interworking IWF.
Network Interworking In Network Interworking, the PCI (Protocol
Control Information) of the protocol and the
payload information used in two similar
networks are transferred transparently by an
IWF of the PE across the PSN. Typically the IWF
of the PE encapsulates the information which is
transmitted by means of an adaptation function
and transfers it transparently to the other
network.
2. PDU Encapsulation
Every PE MUST provide service interfaces to use common service-
specific techniques for encapsulating PDUs from the PWESs. It should
be noted that the PDUs to be encapsulated may or may not contain L2
or L1 header information. This is service specific. Every PWE3
service MUST specify what the PDU is.
A PW header consists of all the header fields in a PW PDU that are
used by the PW egress to determine how to process the PDU. The header
that is used for sending the PW PDUs from the PW ingress to the
egress (e.g. the tunnel label in [MARTINI2]) is not considered as
part of the PW header. It is called PSN tunnel header.
Specific requirements on PDU encapsulation for a PWE3 approach are
listed below.
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2.1. Conveyance of Necessary L2/L1 Header Information
The egress of a PW needs some information, e.g. which native service
the PW PDUs belong to, and possibly some L2 or L1 header information,
in order to know how to process the PDUs received. A PWE3 approach
MUST provide some mechanism for conveying such information from the
PW ingress to the egress. It should be noted that not all such
information must be carried in the PW header of the PW PDUs. Some
information (e.g. service type of a PW) can be stored as state
information at the egress during PW setup.
2.2. PDU Length
A PWE3 approach MUST accommodate variable length PDUs, if variable
length PDUs are allowed by the native service. For example, a PWE3
approach for Frame Relay MUST accommodate variable length frames.
2.3. Encapsulation of Control Messages of the Native Services
It is desirable that the PEs participate as little as possible in the
signaling and maintenance of the native services. However, it is up
to each specific PWE3 approach to specify what the PEs need to do in
this regard.
2.4. Support for Circuit Multiplexing
If a service in its native form is capable of grouping multiple
circuits into a "trunk", e.g. an ATM VP, some mechanism SHOULD be
provided so that a single PW can be used to connect two end-trunks.
From encapsulation perspective, the encapsulation header MUST carry
sufficient information, e.g. VCI of each cell, so that the egress of
the PW can demultiplex individual circuits from the PW.
2.5. Packet Ordering
When packets carrying the PW PDUs traverse a PW, they may arrive at
the egress out of order. For some services, the PW PDUs must be
delivered in order. For such services, some mechanism MUST be
provided for ensuring in-order delivery. Providing a sequence number
in the PW header for each packet is one possible approach.
2.6. Packet Duplication
In rare cases, packets traversing a PW may be duplicated. For some
services, packet duplication is not allowed. For such services some
mechanism MUST be provided to ensure that duplicated packets will not
be delivered. The mechanism may or may not be the same as the
mechanism used to ensure in-order packet delivery.
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3. Carrying the PW PDUs over a Packet-Switched Network
This section describes requirements on how to send packets carrying
the PW PDUs over a packet-switched network (PSN) that provides PWE3
services.
3.1. Setup of Pseudo-Wires
A PW is a tunnel that connects two PWESs. After the L2/L1 PDUs of a
service are encapsulated, they must be sent over the PW to the other
PWES.
Every PWE3 approach MUST define some signaling mechanism for setting
up the PWs. During the setup process, the PEs need to exchange some
information (e.g. learn each other's capability). The signaling
mechanism MUST enable the PEs to exchange all necessary information.
For example, both endpoints must agree on an encapsulation method. As
another example, in order to support circuit multiplexing using ATM
VPs, both PEs must agree on using the VCIs in the PW PDUs to
demultiplex individual VCs from the VP at the PW egress. Which
signaling protocol to use and what information to exchange are
service specific. Every PWE3 approach MUST specify these. Manual
configuration can be considered as a special kind of signaling and is
explicitly allowed.
IP tunnels [MPLSINIP], sessions in a [L2TP] tunnel, or [MPLS] LSPs
can all be used as PWs. Selection of a particular type of PWs is
carrier-dependent and is outside scope of the PWE3 WG.
3.2. Pseudo-Wire MTU
A PW MUST be able to be configured with an PW_MTU. One way to do this
is to set the PW_MTU to (PW_Path_MTU - PW_header -
PSN_tunnel_header). At a PW ingress, if a packet's length exceeds the
PW_MTU, it MAY be dropped. In this case, the management plane of the
ingress PE MAY be notified. Alternatively, a fragmentation mechanism
MAY be defined and used. At a PW egress, if the length of a L2/L1
frame that is restored from a PW PDU exceeds the MTU of destination
PWES, it MAY be dropped. In this case, the management plane of the
egress PE MAY be notified. Alternatively, a fragmentation mechanism
MAY be defined and used.
3.3. Carrying Control Messages of the Native Services
Some native services use control messages for maintaining the
circuits. These control messages may be in-band, e.g. Ethernet flow
control or ATM performance management, or out-of-band, e.g. the
signaling VC of an ATM VP. If such control messages are lost,
functionality of the services will be significantly affected.
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Therefore, it can be desirable to provide higher reliability for
carrying control messages. What mechanisms to use and how to use
those mechanisms for providing higher reliability are outside scope
of the PWE3 WG.
3.4. PSN Tunnel Header Overhead
In order to reduce PSN tunnel header overhead, multiple PDUs MAY be
concatenated before a PSN tunnel header is added. Each PDU still
carries its own PW header so that the egress of the PW knows how to
process it. However, the benefit of concatenating multiple PDUs for
header efficiency should be weighed against the resulting larger
penalty incurred by packet loss.
4. Faithfulness of Emulated Services
An emulated service SHOULD be as similar to the native service as
possible, but it is not REQUIRED that they should be identical. The
applicability statement of a PWE3 service MUST report any limitations
of the emulated service. All limitations between an emulated service
and the corresponding native service can be classified as either
functional or non-functional. Functional limitations are those that
cause some features of the native service to become disabled in the
emulated one. For example, if an emulated Ethernet service introduces
some difference that can cause the Spanning Tree Protocol (STP) to
malfunction, such a difference will be classified as a functional
difference. Other differences are non-functional. For examples,
differences in service quality between an emulated service and the
native one are non-functional.
Some basic requirements on faithfulness of an emulated service are
described below.
4.1. Characteristics of an Emulated Service
Functionally, two CEs that are connected by an emulated service
SHOULD appear directly connected by a native service, although
service quality of the emulated service may be different from that of
a native one. Specifically, the following requirements MUST be met:
1) It MUST be possible to define type (e.g. Ethernet, which is
inherited from the native service), speed (e.g. 100Mbps), and MTU
size for an emulated service.
2) The two endpoints of emulated service #1 and the two endpoints of
emulated service #2 may be connected to the same PE at each end,
respectively. As a result, the PWs of these two emulated services
may share the same physical paths between the two PEs. But from
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the CEs' perspective, each emulated service MUST appear as
unshared, that is, a CE MUST NOT be aware of existence of other
CEs or other emulated services.
3) If an emulated service fails (either at one of the PWESs or in the
middle of the PW), both CEs MUST be notified in a timely manner,
if they will be notified in the native service. The definition of
"timeliness" is service-dependent.
4) If a routing protocol (e.g. IGP) adjacency can be established over
a native service, it MUST be possible to be established over an
emulated service as well. Spanning Tree Protocol (STP) is not
considered as a routing protocol and requirements on support/non-
support of STP is outside scope of this document.
5) The TTL fields of the PW PDUs, if exist, MUST not be changed
inside an emulated service.
4.2. Service Quality of Emulated Services
It is RECOMMENDED but not REQUIRED that an emulated service provide
as high service quality as the native service. However, the PWE3 WG
only defines mechanisms for providing PW emulation, not the services
themselves. What quality to provide for a specific emulated service
is a matter between a service provider (SP) and its customers, and is
outside scope of the PWE3 WG. In fact, different SPs can use the same
PWE3 approach with different QoS mechanisms to provide the same
emulated service with different service quality.
5. Maintenance of Emulated Services
Every PWE3 approach MUST provide mechanisms for maintaining the
working condition of an emulated service.
5.1. Keep-alive
If a native service has keep-alive mechanism, the corresponding
emulated service MUST define a similar mechanism for keep-alive.
5.2. Status Monitoring
Some native services have mechanisms for status monitoring. For
example, ATM supports OAM for this purpose. For such services, the
corresponding emulated services MUST specify how to perform status
monitoring. The mechanisms NEED NOT be defined in this WG. Some
status monitoring mechanisms defined in other WGs, e.g., [LSPPING] or
[MPLSOAM], may be leveraged.
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5.3. Notification of Status Changes
5.3.1. Up/Down Notification
If a native service is bi-directional, the corresponding emulated
service can only be signaled up when the associated PWs, and PSN
tunnels if any, in both directions are functional.
Because the two CEs of an emulated service are not adjacent, a
failure may occur at a place such that one or both physical links
between the CEs and PEs remain up. For example in Figure 1, if the
physical link between CE1 and PE1 fails, the physical link between
CE2 and PE2 will not be affected and will remain up. Unless CE2 is
notified about the remote failure, it will continue to send traffic
over the emulated service to CE1. Such traffic will be discarded at
PE1. Some native services have failure notification so that when the
services fail, both CEs will be notified. For such native services,
the corresponding PWE3 service MUST provide a failure notification
mechanism.
Similarly, if a native service has notification mechanism so that
when a network failure is fixed, all the affected services will
change status from "Down" to "Up", the corresponding emulated service
MUST provide a similar mechanism for doing so.
5.3.2. Misconnection and Payload Mistype
With PWE3, misconnection and payload mistype can occur. A PWE3
approach MAY define some mechanism for detecting and handling
misconnection and payload mistype.
5.3.3. Packet Loss, Corruption, and Out-of-order Delivery
A PW can incur packet loss, corruption, and out-of-order delivery.
This can impact the working condition of an emulated service. Packet
loss, corruption, and out-of-order delivery can be considered as
"generalized bit error" of a PW. If a native service has some
mechanism to deal with bit error, the corresponding PWE3 service
SHOULD provide a similar mechanism.
5.3.4. Other Status Notification
A PWE3 approach MAY provide mechanism for other status notification,
if any.
5.3.5. Collective Status Notification
Status of a group of emulated services may be affected identically by
a single network incidence. For example, when the physical link
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between a CE and a PE fails, all the emulated services that go
through that link will fail. It is likely that there exists a group
of emulated services which all terminate at a remote CE. (There can
be multiple such CEs). Therefore, it is desirable that a single
notification message be used to notify failure of the whole group of
emulated services. A PWE3 approach MAY provide some mechanism for
notifying status changes of a group of emulated circuits. One
possible approach is to associate each emulated service with a group
ID when the PW for that emulated service is set up. Multiple emulated
services can then be grouped by associating them with identical group
ID. In status notification, that group ID can be used to refer all
the emulated services in that group.
5.4. Clock Recovery
For some services, the PEs need to maintain some kind of timing
relationship (e.g. synchronization). The corresponding PWE3 services
MUST provide some mechanism to support that. If time stamps need to
be carried across the PSN, [RTP] MUST be used.
6. Management of Emulated Services
Each PWE3 approach SHOULD provide some mechanisms for network
operators to manage the emulated service. These mechanisms can be in
the forms described below.
SNMP MIBs [SMIV2] MUST be provided for managing each emulated service
as well as pseudo-wire in general. These MIBs SHOULD be created with
the following requirements.
6.2. General MIB Requirements
New MIBs MUST augment or extend where appropriate, existing tables as
defined in other existing service-specific MIBs for existing services
such as MPLS or L2TP. For example, the ifTable as defined in the
Interface MIB [IFMIB] MUST be augmented to provide counts of out-of-
order packets. A second example is the extension of the MPLS-TE-MIB
[TEMIB] when emulating circuit services over MPLS. Rather than
redefining the tunnelTable so that PWES can utilize MPLS tunnels, for
example, entries in this table MUST instead be extended to add
additional PWES-specific objects. Doing so facilitates a natural
extension of those objects defined in the existing MIBs in terms of
management, as well as leveraging existing agent implementations.
Interfaces implementing a PWES MUST appear as an interface in the
ifTable.
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6.3. Configuration and Provisioning
MIB Tables MUST be designed to facilitate configuration and
provisioning of the PWES.
The MIB(s) MUST facilitate intra-PSN configuration and monitoring of
PWES connections.
6.4. Performance Monitoring
MIBs MUST collect statistics for performance and fault management.
MIBs MUST provide a description of how existing counters are used for
PW emulation and SHOULD not replicate existing MIB counters.
6.5. Fault Management and Notifications
Notifications SHOULD be defined where appropriate to notify the
network operators of any interesting situations, including faults
detected in the PWES.
Objects defined to augment existing protocol-specific notifications
in order to add PWES functionality MUST explain how these
notifications are to be emitted.
6.6. Pseudo-Wire Traceroute
It can be desirable to know the exact path of a PW, especially for
troubleshooting purpose. A PW emulation service MUST support PW
traceroute. One tunnel traceroute approach is defined in [BONICA].
7. Scalability
Scalability requirements for PWE3 are described below.
- Only PEs should be aware of existence of PWs and PWE3 services.
Core network devices SHOULD NOT be exposed to a large number of
PWs.
PWs can be path-oriented or non-path-oriented. For path-oriented
PWs, core network devices must maintain state information for them.
If a large number of path-oriented PWs are used, core network
devices will have to maintain a large amount of state information.
In order to avoid scalability problem, PSN tunnels between PEs can
be introduced. PWs from the same ingress to the same egress are
nested inside the PSN tunnel that is from that ingress to that
egress. By creating such a tunnel hierarchy, individual PWs are
transparent to the core devices. If a specific PWE3 approach uses
path-oriented PWs, PSN tunnels SHOULD be used to improve
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scalability. However, a PSN tunnel is not part of any PW.
Signaling of PSN tunnels NEED NOT be defined in the PWE3 approach
itself. As an example, if LSPs are used as PWs in a PWE3 approach,
they can be nested inside a tunnel LSP from the PW ingress to the
PW egress. The tunnel LSPs can be signaled by any mechanism
defined in [MPLS].
- Circuit multiplexing: circuit multiplexing SHOULD be supported.
- Collective status notification: collective status notification
SHOULD be supported.
8. Other Generic Requirements
[RFC2914] describes the need for congestion control in the Internet,
and discusses what constitute correct congestion control. Any PWE3
approach MUST conform to RFC 2914 and be TCP-friendly in its response
to congestion. The applicability document of a PWE3 approach MUST
provide a statement on RFC 2914 conformance.
9. Non-Requirements
Some non-requirements are mentioned in various sections of this
document. Those work items are outside scope of the PWE3 WG. The
non-requirements are listed below:
- Service interworking;
- Point-to-multipoint or multipoint-to-multipoint PWs;
- Selection of a particular type of PWs;
- Striving to make the emulated services perfectly match their native
services;
- Defining mechanisms for signaling the PSN tunnels;
- Defining how to perform traffic management on packets that carry PW
PDUs;
- Providing security for the PW PDUs;
- Providing any multicast service that is not native to the emulated
medium.
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To illustrate this point, Ethernet transmission to a multicast
IEEE-48 address is considered in scope, while multicast services
like [MARS] that are implemented on top of the medium are out of
scope;
10. Quality of Service (QoS) Considerations
In this document, QoS means satisfactory service quality. It should
not be confused with QoS mechanisms such as Weighted Fair Queuing
(WFQ) or Random Early Detection (RED).
QoS is essential for ensuring that the emulated services are similar
(but not necessarily identical) to their native forms. It is up to
network operators to decide how to provide QoS - They can choose to
rely on over-provisioning and/or deploy some QoS mechanisms.
In order to take advantage of QoS mechanisms defined in other working
groups, e.g. the traffic management schemes defined in DiffServ WG,
it is desirable that some mechanisms exists for differentiating the
packets resulted from PDU encapsulation. These mechanisms need not be
defined in the PWE3 approaches themselves. For example, if the
packets are MPLS or IP packets, their EXP or DSCP fields can be used
for marking and differentiating. A PWE3 approach MAY provide
guidelines for marking and differentiating, e.g. what fields in the
original L2 or L1 headers should be used for determining the EXP/DSCP
value. But the exact procedure of how to perform marking and
differentiating, e.g. specifying the mapping function from Ethernet
.1P field to EXP field, is out of scope.
11. Inter-domain Pseudo-Wires
The PWE3 WG will determine the requirements for having a PW pass
across an administrative boundary. An edge could be a native hand-
off or hand-off to a further PW. The working group may analyze
requirements for both security and performance for the inter-
administration technology. This topic is for further study.
12. Security Considerations
12.1. Security Considerations for the Signaling/Control Channel
If a signaling/control channel is used in a PWE3 approach, some
security mechanism MUST be provided to ensure integrity of the
information transmitted across the signaling/control channel.
12.2. Security Considerations for the PW PDUs
Providing security for the PW PDUs is outside scope of the PWE3 WG.
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13. Deployment Considerations
Transition from using separate networks for TDM, ATM, Frame Relay and
IP services to using a single network for multiple services requires
careful planning and execution. This is an important topic for
further study.
14. Acknowledgments
Some requirements specified in this document were originally
articulated in a number of documents including [MARTINI1],
[MARTINI2], [CES], and [SFBS]. The authors would like to acknowledge
authors of those documents. The authors would also like to
acknowledge the input and comments from Eric Rosen, Tricci So and Ron
Cohen.
15. References
[BONICA] R. Bonica, K. Kompella, and D. Meyer, "Tracing Requirements
for Generic Tunnels", <draft-bonica-tunneltrace-01.txt>,
work in progress, Feb. 2001.
[CES] A. Malis et al, "SONET/SDH Circuit Emulation Service Over
MPLS (CEM) Encapsulation" , work in progress, April 2001.
[GRE] D. Farinacci, T. Li, S. Hanks, D. Meyer, P. Traina, "Generic
Routing Encapsulation (GRE)", RFC2784, March 2000.
[IFMIB] K. McCloghrie, and F. Kastenholtz, "The Interfaces Group MIB
using SMIv2", RFC 2233, Nov. 1997.
[L2TP] W.M. Townsley, A. Valencia, A. Rubens, G. Singh Pall, G.
Zorn, B. Palter, "Layer Two Tunneling Protocol (L2TP)", RFC
2661, August 1999.
[LSPPING] P. Pan, N. Sheth, and D. Cooper, "Detecting Data Plane
Liveliness in RSVP-TE", <draft-pan-lsp-ping-00.txt>, work in
progress, July 2001.
[MARS] G. Armitage, "Support for Multicast over UNI 3.0/3.1 based
ATM Networks", RFC2022, November 1996
[MARTINI1] L. Martini et al, "Transport of Layer 2 Frames Over MPLS",
<draft-martini-l2circuit-trans-MPLS-06.txt>, work in
progress, May 2001.
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[MARTINI2] L. Martini et al, "Encapsulation Methods for Transport of
Layer 2 Frames Over MPLS", <draft-martini-l2circuit-encap-
MPLS-02.txt>, work in progress, May 2001.
[MPLS] E. Rosen, A. Viswanathan, and R. Callon, "Multiprotocol
Label Switching Architecture", RFC3031, January 2001
[MPLSINIP] P. Doolan, Y. Katsube, A. Malis, R. Wilder, T. Worster,
"MPLS Label Stack Encapsulation in IP", <draft-worster-
mpls-in-ip-04.txt>, work in progress, Feb. 2001.
[MPLSOAM] N. Harrison, P. Willis, S. Davari, B. Mack-Crane, H. Ohta,
"OAM Functionality for MPLS Networks", <draft-harrison-
mpls-oam-00.txt>, work in progress, Feb. 2001.
[TEMIB] C. Srinivasan, A. Viswanathan, and T. Nadeau, "MPLS Traffic
Engineering Management Information Base Using SMIv2",
<draft-ietf-mpls-te-mib-05.txt>, work in progress, November
2000.
[PATE] P. Pate, X. Xiao, T. So, C. White, and K. Kompella,
"Framework for Pseudo-Wire Emulation Edge-to-Edge (PWE3)",
<draft-pate-pwe3-framework-00.txt>, work in progress, May
2001.
[RFC2914] S.Floyd, "Congestion Control Principles", RFC 2914, Sept.
2000.
[RTP] H. Schulzrinne, S. Casner, R. Frederick, and V. Jacobson,
"RTP: A Transport Protocol for Real-Time Applications",
RFC1889, January 1996.
[SFBS] B. St-Denis, D. Fedyk, A. Bhatnagar, A. Siddiqui, R.
Hartani, and T. So, "Multi-service over MPLS", <draft-
stdenis-ms-over-mpls-00.txt>, work in progress, Nov. 2000.
[SMIV2] J. Case, K. McCloghrie, M. Rose, and S. Waldbusser,
"Structure of Management Information for Version 2 of the
Simple Network Management Protocol (SNMPv2)", RFC 1902,
January 1996.
16. Authors' Addresses
XiPeng Xiao
Photuris, Inc.
2025 Stierlin Court
Mountain View, CA 94043
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Email: xxiao@photuris.com
Danny McPherson
Amber Networks, Inc.
48664 Milmont Drive
Fremont, CA 94538
Email: danny@ambernetworks.com
Prayson Pate
Overture Networks
P. O. Box 14864
RTP, NC, USA 27709
Email: prayson.pate@overturenetworks.com
Craig White
Level 3 Communications, LLC.
1025 Eldorado Blvd.
Broomfield, CO, 80021
e-mail: Craig.White@Level3.com
Kireeti Kompella
Juniper Networks, Inc.
1194 N. Mathilda Ave.
Sunnyvale, CA 94089
Email: kireeti@juniper.net
Vijay Gill
Metromedia Fiber Network Inc.
8075 Leesburg Pike, Suite 300
Vienna, VA 22182
Email: vgill@mfnx.net
Thomas D. Nadeau
Cisco Systems, Inc.
250 Apollo Drive
Chelmsford, MA 01824
Email: tnadeau@cisco.com
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17. Full Copyright Section
Copyright (C) The Internet Society (2000). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
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English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
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TASK FORCE DISCLAIMS 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
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