One document matched: draft-ietf-l1vpn-applicability-basic-mode-03.txt
Differences from draft-ietf-l1vpn-applicability-basic-mode-02.txt
Network Working Group
Internet Draft Tomonori Takeda (Editor)
Intended Status: Informational NTT
Expires: April 2008 October 2007
Applicability Statement for Layer 1 Virtual Private Networks (L1VPNs)
Basic Mode
draft-ietf-l1vpn-applicability-basic-mode-03.txt
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Abstract
This document provides an applicability statement on the use of
Generalized Multiprotocol Label Switching (GMPLS) protocols and
mechanisms to support Basic Mode Layer 1 Virtual Private Networks
(L1VPNs).
L1VPNs provide customer services and connectivity at layer 1 over
layer 1 networks. The operation of L1VPNs is divided into the Basic
Mode and the Enhanced Mode where the Basic Mode of operation does not
feature any exchange of routing information between the layer 1
network and the customer domain. This document examines how GMPLS
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protocols can be used to satisfy the requirements of a Basic Mode
L1VPN.
Table of Contents
1. Introduction...................................................2
1.1 Terminology...................................................3
2. Basic Mode Overview............................................3
3. Supported Network Types........................................4
3.1 Data Plane....................................................4
3.2 Control Plane.................................................4
4. Addressing.....................................................5
5. Provider Control of its Infrastructure.........................5
5.1 Provisioning Model............................................5
5.2 PE-PE Segment Control.........................................6
5.2.1 Path Computation and Establishment..........................6
5.2.2 Resource Management.........................................7
5.2.3 Consideration of CE-PE TE information.......................7
5.3 Connectivity Restriction......................................8
6. Customer Control of its L1VPN..................................8
6.1 Topology Control..............................................8
6.2 Note on Routing...............................................8
7. Scalability and Resiliency.....................................9
7.1 Scalability...................................................9
7.2 Data Plane Resiliency........................................10
7.3 Control Plane Resiliency.....................................11
8. Security......................................................11
8.1 Topology Confidentiality.....................................11
8.2 External Control of the Provider Network.....................12
8.3 Data Plane Security..........................................13
8.4 Control Plane Security.......................................13
9. Manageability Considerations..................................14
10. IANA Considerations..........................................14
11. References...................................................14
11.1 Normative References........................................14
11.2 Informative References......................................15
12. Acknowledgments..............................................16
13. Authors' Addresses...........................................16
14. Intellectual Property Consideration..........................17
15. Full Copyright Statement.....................................17
1. Introduction
This document provides an applicability statement on the use of
Generalized Multiprotocol Label Switching (GMPLS) protocols and
mechanisms to Basic Mode Layer 1 Virtual Private Networks (L1VPNs) as
specified in [RFC4847].
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The operation of L1VPNs is divided into the Basic Mode and the
Enhanced Mode. The Basic Mode of operation does not feature any
exchange of routing information between the layer 1 network and the
customer domain, while the Enhanced Mode of operation features
exchange of routing information between the layer 1 network and the
customer domain.
The main GMPLS protocols and mechanisms applicable to the L1VPN Basic
Mode are [L1VPN-BM], [L1VPN-BGP-DISC], and [L1VPN-OSPF-DISC], along
with several other documents referenced within this document.
Note that discussion in this document is focused on areas where GMPLS
protocols and mechanisms are relevant.
1.1 Terminology
The reader is assumed to be familiar with the terminology in
[RFC3031], [RFC3209], [RFC3471], [RFC3473], [RFC4202], [RFC4026] and
[RFC4847].
2. Basic Mode Overview
As described in [RFC4847], in the Basic Mode service model, there is
no routing exchange between the Customer Edge (CE) and the Provider
Edge (PE). CE-CE L1VPN connections (i.e., CE-CE VPN connection in
RFC4847) are set up by GMPLS signaling between the CE and the PE, and
then across the provider network. A L1VPN connection is limited to
the connection between CEs belonging to the same L1VPN.
Note that in L1VPNs, routing operates within the provider network and
may be used by PEs to exchange information specific to the L1VPNs
supported by the provider network (e.g., membership information).
In the L1VPN Basic Mode, the provider network is completely under the
control of the provider. This includes the PE-PE segment of the CE-CE
L1VPN connection that is controlled and computed by the provider (PE-
PE segment control). On the other hand, the L1VPN itself, constructed
from a set of CEs and the L1VPN connections provided by the provider,
is under the control of each customer. This includes that a customer
can request between which CEs a connection is to be established
(topology control). Note that a customer may outsource the management
of its L1VPN to a third party, including to the provider itself.
There is a confidentiality requirement between the provider and each
customer.
[L1VPN-BM], which extends [RFC4208], specifies GMPLS signaling to
establish CE-CE L1VPN connections.
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[L1VPN-BGP-DISC] and [L1VPN-OSPF-DISC] specify alternative mechanisms
to exchange L1VPN membership information between PEs, based on BGP
and OSPF respectively.
3. Supported Network Types
3.1 Data Plane
The provider network can be constructed from any type of layer 1
switches, such as Time Division Multiplexing (TDM) switches, Optical
Cross-Connects (OXCs), or Photonic Cross-Connects (PXCs).
Furthermore, a PE may be an Ethernet Private Line (EPL) type of
device, that maps Ethernet frames onto layer 1 connections (by means
of Ethernet over TDM etc.). The provider network may be constructed
from switches providing a single switching granularity (e.g., only
VC3 switches), or from switches providing multiple switching
granularities (e.g., from VC3/VC4 switches, or from VC3 switches and
OXCs). The provider network may provide a single type of L1VPN
connection (e.g., VC3 connections only), or multiple types of
connection (e.g., VC3/VC4 connections, or VC3 connections and
wavelength connections).
A CE does not have to have the capability to switch at layer 1, but
it must be capable of receiving a layer 1 signal and either switching
it or terminating it with adaptation.
As described in [RFC4847] and [L1VPN-BM], a CE and a PE are connected
by one or more links. A CE may also be connected to more than one PE,
and a PE may have more than one CE connected to it.
A CE may belong to a single L1VPN, or to multiple L1VPNs, and a PE
may support one or more L1VPNs through a single CE or through
multiple CEs.
3.2 Control Plane
The provider network is controlled by GMPLS. L1VPN Basic Mode
provider networks are limited to a single AS within the scope of this
document. Multi-AS Basic Mode L1VPNs are for future study.
As described in [RFC4847] and [L1VPN-BM], a CE and a PE need to be
connected by at least one control channel. It is necessary to
disambiguate control plane messages exchanged between a CE and a PE
if the CE-PE relationship is applicable to more than one L1VPN. This
makes it possible to determine to which L1VPN such control plane
messages apply. Such disambiguation can be achieved by allocating a
separate control channel to each L1VPN (either using a separate
physical channel, a separate logical channel such as an IP tunnel, or
using separate addressing).
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GMPLS allows any type of control channel to be used, as long as there
is IP level reachability. In the L1VPN context, instantiation of a
control channel between a CE and a PE may differ depending on
security requirements, etc. This is discussed in Section 8.
4. Addressing
As described in [L1VPN-BM], the L1VPN Basic Mode allows that customer
addressing realms overlap with each other, and also overlap with the
service provider addressing realm. That is, a customer network may
re-use addresses used by the provider network, and may re-use
addresses used in another customer network supported by the same
provider network. This is the same as in any other VPN model.
In addition, the L1VPN Basic Mode allows a CE-PE control channel
addressing realm overlap. That is, a CE-PE control channel address
(CE's address of this control channel and PE's address of this
control channel) is unique within the L1VPN they belong to, but not
necessarily unique across multiple L1VPNs.
Furthermore, once a L1VPN connection has been established, the L1VPN
Basic Mode does not enforce any restriction on address assignment for
this L1VPN connection (treated as a link) for customer network
operation (e.g., IP network, MPLS network).
5. Provider Control of its Infrastructure
5.1 Provisioning Model
As described in [L1VPN-BM], for each L1VPN that has at least one
customer-facing port on a given PE, the PE maintains a Port
Information Table (PIT) associated with that L1VPN. A PIT provides a
cross-reference between Customer Port Indices (CPIs) and Provider
Port Indices (PPIs) and contains a list of <CPI, PPI> tuples for all
the ports within the L1VPN. In addition, for local PE ports of a
given L1VPN the PE retains an identifier known as the VPN-PPI, and
this is stored in the PIT with the <CPI, PPI> tuples.
When a new CE belonging to one or more L1VPNs is added to a PE, PIT
entries associated to those L1VPNs need to be configured on the PE.
Section 4 of [L1VPN-BM] specifies such procedures:
- If no PIT exists for the L1VPN on the PE, a new PIT is created by
the provider and associated with the VPN identifier.
- The PIT (new or pre-existing) is updated to include information
related to the newly added CE. The VPN-PPI, PPI, and CPI are
installed in the PIT. Note that the PPI is well-known by the PE,
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but the CPI must be discovered either through manual configuration
or automatically by mechanisms such as the Link Management Protocol
(LMP) [RFC4204]. In addition, a CE to PE control channel needs to
be configured.
- The updated PIT information needs to be configured in the PITs on
remote PE associated with the L1VPN. For such purposes, manual
configuration or some sort of auto-discovery mechanisms can be
used. [L1VPN-BGP-DISC] and [L1VPN-OSPF-DISC] specify alternative
auto-discovery mechanisms.
- In addition, remote PIT information associated with the L1VPN needs
to be configured on this PE if the PIT has been newly created.
Again, this can be achieved through manual configuration or through
auto-discovery, [L1VPN-BGP-DISC] and [L1VPN-OSPF-DISC].
When L1VPN membership of an existing CE changes, or when a CE is
removed from a PE, similar procedures need to be applied to update
the local and remote PITs.
5.2 PE-PE Segment Control
In the L1VPN Basic Mode, a PE-PE segment of a CE-CE L1VPN connection
is completely under the control of provider network.
5.2.1 Path Computation and Establishment
A PE-PE segment of a CE-CE L1VPN connection may be established based
on various policies. Those policies can be applied per L1VPN or per
L1VPN connection. The policy is configured by the provider, possibly
based on the contracts with each customer.
Examples of PE-PE segment connection establishment polices supported
in the L1VPN Basic Mode are as follows.
- Policy 1: On-demand establishment, on-demand path computation
- Policy 2: On-demand establishment, pre-computed path
- Policy 3: Pre-establishment, pre-computed path
In each policy, the PE-PE path may be computed by the local PE, or by
a path computation entity outside of the local PE (e.g., a Path
Computation Element (PCE) [RFC4655], or a management system).
In policies 2 and 3, pre-computation of paths (and pre-establishment
if applicable) can be done at the network planning phase, or just
before signaling (e.g., triggered by an off-line customer request).
As the result of pre-computation (and pre-establishment), there could
be multiple PE-PE segments for a specific pair of PEs. When a PE
receives a Path message from a CE for a L1VPN connection, a PE needs
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to determine which PE-PE segment to use. In such cases, the provider
may want to control:
- Which L1VPN uses which PE-PE L1VPN segment.
- Which CE-CE L1VPN connection uses which PE-PE L1VPN segment.
The former requires mapping between the PIT and the PE-PE segment.
The latter requires some more sophisticated mapping method, for
example:
- Mapping between individual PIT entries and PE-PE segments.
- Use of a Path Key ID [Conf-Segment] supplied by the provider to the
CE, and signaled by the CE as part of the L1VPN connection request.
The L1VPN Basic Mode does not preclude usage of other methods, if
applicable.
In policy 3, stitching or nesting is necessary in order to map the
CE-CE L1VPN connection to a pre-established PE-PE segment.
5.2.2 Resource Management
The provider network may operate resource management based on various
policies. These policies can be applied per L1VPN or per L1VPN
connection. The policy is configured by the provider, possibly based
on the contracts with each customer.
For example, a provider may choose to partition the resources of the
provider network for limited use by different L1VPNs or customers.
Such a function might be achieved within the scope of the Basic Mode
using resource affinities [RFC3209], but the details of per-L1VPN
resource models (especially in terms of CE-PE routing) are considered
as part of the Enhanced Mode.
5.2.3 Consideration of CE-PE TE information
[L1VPN-OSPF-DISC] and [BGP-TE] allow CE-PE TE link information to be
injected into the provider network. This may be helpful for the
ingress PE to prevent connection setup failure due to lack of
resources or incompatible switching capabilities on remote CE-PE TE
links.
Furthermore, the L1VPN Basic Mode allows a remote CE to be reached
through more than one TE link connected to the same PE (single-homed)
or to different PEs (dual-homed). In such cases, to facilitate route
choice, the ingress CE needs to initiate signaling by specifying the
egress CE's router ID not the egress CPI in the Session Object and
ERO (if present) so as to not constrain the choice of route within
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the provider network. Therefore, the CE's router ID needs to be
configured in the PITs.
Note that, as described in Section 7.2, consideration of the full
feature set enabled by dual-homing (such as resiliency) is out of
scope of the L1VPN Basic Mode.
5.3 Connectivity Restriction
The L1VPN Basic Mode allows restricting connection establishment
between CEs belonging to the same L1VPN for policy reasons (including
L1VPN security). Since the PIT at each PE is associated with a L1VPN,
this function can be easily supported. The restriction can be applied
at the ingress PE or at the egress PE according to the applicable
restriction policy, but note that applying the policy at the egress
may waste signaling effort within the network as L1VPN connections
are pointlessly attempted.
In addition, the L1VPN Basic Mode does not restrict use of any
advanced admission control based on various policies.
6. Customer Control of its L1VPN
6.1 Topology Control
In the L1VPN Basic Mode, L1VPN connection topology is controlled by
the customer. That is, a customer can request
setup/deletion/modification of L1VPN connections using signaling
mechanisms specified in [L1VPN-BM].
Also note that if there are multiple CE-PE TE links (single-homed or
multi-homed), a customer can specify which CE-PE TE link to use to
support any L1VPN connection. Alternatively, a customer may let the
provider choose the CE-PE TE link at the egress side, as described in
Section 5.2.3.
6.2 Note on Routing
A CE needs to obtain the remote CPI to which it wishes to request a
connection. Since, in the L1VPN Basic Mode, there is no routing
information exchange between a CE and a PE, there is no dynamic
mechanism supported as part of the Basic Mode L1VPN service, and the
knowledge of remote CPIs must be acquired in a L1VPN-specific way,
perhaps through configuration or through a directory server.
If a L1VPN is used by a customer to operate a private IP network, the
customer may wish to form routing adjacencies over the CE-CE L1VPN
connections. The L1VPN Basic Mode does not enforce any restriction on
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such operation by a customer, and the use made of the L1VPN
connections is transparent to the provider network.
Furthermore, if a L1VPN is used by a customer to operate a private
Multiprotocol Label Switching (MPLS) or GMPLS network, the customer
may wish to treat a L1VPN connection as a Traffic Engineering (TE)
link, and this requires a CE-CE control channel. Note that a
Forwarding Adjacency [RFC4206] cannot be formed from the CE-CE L1VPN
connection in the Basic Mode because there is no routing exchange
between CE and PE - that is, the customer network and the provider
network do not share a routing instance, and the customer control
channel cannot be carried within the provider control plane. But
where the CE provides suitable adaptation (for example, where the
customer network is a packet-switched MPLS or GMPLS network) the
customer control channel may be in-band and a routing adjacency may
be formed between the CEs using the L1VPN connection. Otherwise, CE-
CE control plane connectivity may form part of the L1VPN service
provided to the customer by the provider and may be achieved within
the L1VPN connection (for example, through the use of overhead bytes)
or through a dedicated control channel connection or tunnel. The
options available are discussed further in Section 10.2 of
[RFC4847].
7. Scalability and Resiliency
7.1 Scalability
There are several factors that impact scalability.
o Number of L1VPNs (PITs) configured on each PE
With the increase of this number, information to be maintained on
the PE increases. Theoretically, the upper limit of the number of
L1VPNs supported in a provider network is governed by how the ID
associated with a L1VPN is allocated, and the number of PITs
configured on each PE is limited by this number. However,
implementations may impose arbitrary limits on the number of PITs
supported by any one PE.
o Number of CE-PE TE links for each L1VPN
With the increase of this number, information to be maintained in
each PIT increases. When auto-discovery mechanisms are used, the
amount of information that an auto-discovery mechanism can support
may restrict this number.
Note that [L1VPN-OSPF-DISC] floods membership information not only
among PEs, but also to all P nodes. This may lead to scalability
concerns, compared to [L1VPN-BGP-DISC], which distributes
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membership information only among PEs. Alternatively, a separate
instance of the OSPF protocol can be used just between PEs for
distributing membership information. In such a case, Ps do not
participate in flooding.
Note that in the L1VPN Basic Mode, a PE needs to obtain only CE-PE
TE link information, and not customer routing information, which is
quite different from the mode of operation of a L3VPN. Therefore,
the scalability concern is considered to be less problematic.
o Number of L1VPN connections
With the increase of this number, information to be maintained on
each PE/P increases. When stitching or nesting is used, state to
be maintained at each PE increases compared to when connectivity is
achieved without stitching or nesting.
However, in a layer 1 core, this number is always bounded by the
available physical resource because each LSP uses a separate label
which is directly bound to a physical, switchable resource
(timeslot, lambda, fiber). Thus, it can be safely assumed that the
PEs/Ps can comfortably handle the number of LSPs that they may be
called on to switch for a L1VPN.
7.2 Data Plane Resiliency
The L1VPN Basic Mode supports following data plane recovery
techniques [L1VPN-BM].
o PE-PE segment recovery
The CE indicates to protect the PE-PE segment by including
Protection Object specified in [RFC4873] in the Path message and
setting Segment Recovery Flags. The CE may also indicate the branch
and merge nodes by including Secondary Explicit Route Object.
Depending on the signaling mechanisms used within the provider
network, details on how to protect the PE-PE segment may differ as
follows.
- If LSP stitching or LSP hierarchy are used to provision the PE-PE
segment, then the PE-PE LSP may be protected using end-to-end
recovery within the provider network.
- If the CE-CE L1VPN connection is a single end-to-end LSP
(including if session shuffling is used), then the PE-PE LSP
segment may be protected using segment protection [RFC4873]
o CE-PE recovery and PE-PE recovery via link protection
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The CE indicates to protect ingress and egress CE-PE links as well
as links within the provider network by including Protection Object
specified in [RFC3473] and setting Link Flags in the Path message.
- The ingress and egress CE-PE link may be protected at a lower
layer
Depending on the signaling mechanisms used within the provider
network, details on how to protect links within the provider
network may differ as follows.
- If the PE-PE segment is provided as a single TE link (stitching
or hierarchy) so that the provider network can perform simple PE-
to-PE routing, then the TE link may offer link-level protection
through the instantiation of multiple PE-PE LSPs.
- The PE-PE segment may be provisioned using only link-protected
links within the core network.
Note that it is not possible to protect only the CE-PE portion or the
PE-PE portion by link protection because the CE-CE signaling request
asks for a certain level of link protection on all links used by the
LSP. Also, it is not possible to protect the CE-PE portion by link
recovery and the PE-PE portion by segment recovery at the same time.
CE-CE recovery through the use of connections from one CE to diverse
PEs (i.e., dual-homing) is not supported in the L1VPN Basic Mode.
7.3 Control Plane Resiliency
The L1VPN Basic Mode allows use of GMPLS control plane resiliency
mechanisms. This includes, but not limited to, control channel
management in LMP [RFC4204] and fault handling in RSVP-TE ([RFC3473]
and [RSVP-GR]) between a CE and a PE as well as within the provider
network.
8. Security
Security considerations are described in [RFC4847], and this section
describes how these considerations are addressed in the L1VPN Basic
Mode.
8.1 Topology Confidentiality
As specified in [L1VPN-BM], a provider's topology confidentiality is
preserved by the Basic Mode. Since there is no routing exchange
between PE and CE, the customer network can gather no information
about the provider network. Further, as described in Section 4 of
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[RFC4208], a PE may filter the information present in a Record Route
Object (RRO) that is signaled from the provider network to the
customer network. In addition, as described in Section 5 of [RFC4208]
and Section 4.4 of [L1VPN-BM], when a Notify message is sent to a CE,
it is possible to hide the provider internal address. This is
accomplished by a PE updating the Notify Node Address with its own
address when the PE receives NOTIFY_REQUEST object from the CE.
Even in the case of pre-computed and/or pre-signaled PE-PE segments,
provider topology confidentiality may be preserved through the use of
path key IDs [Conf-Segment].
The customer's topology confidentiality cannot be completely hidden
from the provider network. At the least, the provider network will
know about the addresses and locations of CEs. Other customer
topology information will remain hidden from the provider in the
Basic Mode although care may be needed to protect the customer
control channel as described in Section 8.4.
The provider network is responsible for maintaining confidentiality
of topology information between customers and across L1VPNs. Since
there is no distribution of routing information from PE to CE in the
Basic Mode, there is no mechanism by which the provider could
accidentally, or deliberately but automatically, distribute this
information.
8.2 External Control of the Provider Network
The provider network is protected from direct control from within
customer networks through policy and through filtering of signaling
messages.
There is a service-based policy installed at each PE that directs how
a PE should react to a L1VPN connection request received from any CE.
Each CE is configured at the PE (or through a policy server) for its
membership of a L1VPN, and so CEs cannot dynamically bind to a PE or
join a L1VPN. With this configuration comes the policy that tells the
PE how to react to a L1VPN connection request (for example, whether
to allow dynamic establishment of PE-PE connections). Thus, the
provider network is protected against spurious L1VPN connection
requests and can charge for all L1VPN connections according to the
service agreement with the customers. Hence the provider network is
substantially protected against denial of service attacks.
At the same time, if a Path message from a CE contains an Explicit
Route Object (ERO) specifying the route within provider network, it
is rejected by the PE. Thus, the customer network has no control over
the resources in the provider network.
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8.3 Data Plane Security
As described in [RFC4847], at layer 1, data plane information is
normally assumed to be secure once connections are established since
those connections are dedicated to L1VPNs. That is, it is not
possible to communicate unless there is a connection.
In order to protect against mis-delivery, each L1VPN connection is
restricted to use only within a single L1VPN. That is, a L1VPN
connection does not connect CEs that are in different L1VPNs. In
order to realize this, the identity of CEs is assured as part of the
service contract. And upon receipt of a request for connection setup,
the provider network assures that the connection is requested between
CEs belonging to the same L1VPN. This is achieved as described in
Section 5.3.
Furthermore, customers can apply their own security mechanisms to
protect data plane information (CE-CE security). This includes IPsec
for IP traffic.
8.4 Control Plane Security
There are two aspects for control plane security.
First, the entity connected over a CE-PE control channel must be
identified. This is done when a new CE is added as part of the
service contract and the necessary control channel is established.
This identification can use authentication procedures available in
RSVP-TE [RFC3209].
Second, it must be possible to secure communication over a CE-PE
control channel. If a communication channel between the customer and
the provider (control channel, management interface) is physically
separate per customer, the communication channel could be considered
as secure. However, when the communication channel is physically
shared among customers, security mechanisms need to be available and
should be enforced. RSVP-TE [RFC3209] provides for tamper-protection
of signaling message exchanges. IPsec tunnels can further be used for
this purpose.
Note that even in the case of physically separate communication
channels, customers may wish to apply security mechanisms, such as
IPsec, to assure higher security, and such mechanisms must be
available.
Furthermore, the provider network needs mechanisms to detect Denial
of Service (DoS) attacks and to protect against them reactively and
proactively. In the Basic Mode, this relies on management systems.
For example, management systems collect and analyze statistics on
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signaling requests from CEs, and protect against malicious behaviors
where necessary.
Lastly, it should be noted that customer control plane traffic
carried over the provider network between CEs needs to be protected.
Such protection is normally the responsibility of the customer
network and can use the security mechanisms of the customer signaling
and routing protocols (for example, RSVP-TE [RFC3209]) or may use
IPsec tunnels between CEs. CE-CE control plane security may form part
of the data plane protection where the control plane traffic is
carried in-band in the L1VPN connection. Where the CE-CE control
plane connectivity is provided as an explicit part of the L1VPN
service by the provider, control plane security should form part of
the service agreement between the provider and customer.
9. Manageability Considerations
Manageability considerations are described in [RFC4847]. In the L1VPN
Basic Mode, we rely on management systems for various aspects of the
different service functions, such as fault management, configuration
and policy management, accounting management, performance management,
and security management (as described in Section 8).
In order to support various management functionalities, MIB modules
need to be supported. In particular, the GMPLS TE MIB (GMPLS-TE-STD-
MIB) [RFC4802] can be used for GMPLS-based traffic engineering
configuration and management, while the TE Link MIB (TE-LINK-STD-MIB)
[RFC4220] can be used for TE links configuration and management.
10. IANA Considerations
This informational document makes no requests for IANA action.
[RFC Editor - please remove this entire section before publication]
11. References
11.1 Normative References
[RFC4847] Takeda, T., Editor "Framework and Requirements for
Layer 1 Virtual Private Networks", RFC 4847, April
2007.
[RFC4208] Swallow, G., et al., "Generalize Multiprotocol
Label Switching(GMPLS) User-Network Interface:
Resource ReserVation Protocol-Traffic Engineering
(RSVP-TE) Support for the Overlay Model," RFC4208,
October 2005.
[L1VPN-BM] Fedyk, D., and Rekhter, Y., Editors, "Layer 1
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VPN Basic Mode", draft-ietf-l1vpn-basic-mode,
work in progress.
[L1VPN-BGP-DISC] Ould-Brahim, H., Fedyk, D., and Rekhter, Y.,
"BGP-based Auto-Discovery for L1VPNs", draft-ietf-
l1vpn-bgp-auto-discovery, work in progress.
[L1VPN-OSPF-DISC] Bryskin, I., and Berger, L., "OSPF Based L1VPN
Auto-Discovery", draft-ietf-l1vpn-ospf-auto-
discovery, work in progress.
[RFC4873] Berger, L., et al., "GMPLS Based Segment
Recovery", RFC 4873, May 2007.
[RFC3031] Rosen, E., Viswanathan, A. and R. Callon,
"Multiprotocol label switching Architecture", RFC
3031, January 2001.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T.,
Srinivasan, V. and G. Swallow, "RSVP-TE:
Extensions to RSVP for LSP Tunnels", RFC 3209,
December 2001.
[RFC3471] Berger, L., Editor, "Generalized Multi-Protocol
Label Switching (GMPLS) Signaling Functional
Description", RFC 3471, January 2003.
[RFC3473] Berger, L., Editor "Generalized Multi-Protocol
Label Switching (GMPLS) Signaling - Resource
ReserVation Protocol-Traffic Engineering (RSVP-TE)
Extensions", RFC 3473, January 2003.
[RFC4202] Kompella, K., et al., "Routing Extensions in
Support of Generalized Multi-Protocol Label
Switching (GMPLS)", RFC 4202, October 2005.
[RFC4026] Anderssion, L., and Madsen, T., "Provider
Provisioned Virtual Private Network (VPN)
Terminology", RFC 4026, March 2005.
11.2 Informative References
[RFC4204] Lang, J., "Link Management Protocol (LMP)",
RFC 4204, October 2005.
[RFC4206] Kompella, K., Rekhter, Y., "Label Switched Paths
(LSP) Hierarchy with Generalized Multi-Protocol
Label Switching (GMPLS) Traffic Engineering (TE)",
RFC 4206, October 2005.
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[BGP-TE] Ould-Brahim, H., Fedyk, D., and Rekhter, Y.,
"Traffic Engineering Attribute", draft-fedyk-bgp-
te-attribute, work in progress.
[RFC4655] Farrel, A., Vasseur, JP, Ash, J., "Path
Computation Element (PCE) Architecture", RFC 4655,
August 2006.
[Conf-Segment] Bradford, R., Editor, "Preserving Topology
Confidentiality in Inter-Domain Path Computation
and Signaling", draft-ietf-pce-path-key, work in
progress.
[RFC4802] Nadeau, T., Farrel, A., Editors, "Generalized
Multiprotocol Label Switching (GMPLS) Traffic
Engineering Management Information Base", RFC
4802, February 2007.
[RFC4220] Dubuc, M., Nadeau, T., Lang, J., "Traffic
Engineering Link Management Information Base", RFC
4220, November 2005.
[RSVP-GR] Satyanarayana, A., and Rahman, R., "Extensions to
GMPLS RSVP Graceful Restart", draft-ietf-ccamp-
rsvp-restart-ext, work in progress.
12. Acknowledgments
Authors would like to thank Ichiro Inoue for valuable comments. In
addition, authors would like to thank Marco Carugi and Takumi Ohba
for valuable comments in the early development of this document.
13. Authors' Addresses
Deborah Brungard (AT&T)
Rm. D1-3C22 - 200 S. Laurel Ave.
Middletown, NJ 07748, USA
Phone: +1 732 4201573
Email: dbrungard@att.com
Adrian Farrel
Old Dog Consulting
Phone: +44 (0) 1978 860944
Email: adrian@olddog.co.uk
Hamid Ould-Brahim
Nortel Networks
P O Box 3511 Station C
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Ottawa, ON K1Y 4H7 Canada
Phone: +1 (613) 765 3418
Email: hbrahim@nortel.com
Dimitri Papadimitriou (Alcatel-Lucent)
Francis Wellensplein 1,
B-2018 Antwerpen, Belgium
Phone: +32 3 2408491
Email: dimitri.papadimitriou@alcatel-lucent.be
Tomonori Takeda
NTT Network Service Systems Laboratories, NTT Corporation
3-9-11, Midori-Cho
Musashino-Shi, Tokyo 180-8585 Japan
Phone: +81 422 59 7434
Email: takeda.tomonori@lab.ntt.co.jp
14. Intellectual Property Consideration
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.
15. Full Copyright Statement
Copyright (C) The IETF Trust (2007).
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.
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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.
T.Takeda, et al. Expires April 2008 [Page 18]
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