Internet Draft Ananth Nagarajan
Expiration Date: April 2003 Sprint
Category: Informational (Editor)
October 2002
Generic Requirements for Provider Provisioned VPN
<draft-nagarajan-ppvpn-generic-reqts-01.txt>
Status of this Memo
This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of [RFC-2026].
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Abstract
This document described generic requirements for Provider Provisioned
Virtual Private Networks (PPVPN). The requirements are categorized into
service requirements, provider requirements and engineering
requirements. These requirements are not specific to any particular
type of PPVPN technology, but rather apply to all PPVPN technologies.
Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
NOT","SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
this document are to be interpreted as described in [RFC-2119].
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1. Introduction
1.1. Summary for Sub-IP area
This document is an output of the design team formed to develop
requirements for PPVPNs in the PPVPN working group. As such this
work fits within the scope of the PPVPN working group. This
document discusses generic PPVPN requirements categorized as
service, provider and engineering requirements. These are
independent of any particular type of PPVPN technology.
1.2. Problem Statement
Corporations and other organizations have become increasingly
dependent on their networks for tele- and datacommunication. The
data communication networks were originally built as Local Area
Networks (LAN). Over time the possibility to interconnect the
networks on different sites has become more and more important. The
connectivity for corporate networks has been supplied by service
providers, mainly as FR or ATM connections, but over recent years
also as Ethernet and IP-based tunnels. This type of network,
interconnecting a number of sites over a shared network
infrastructure is called Virtual Private Network (VPN). If the sites
belong to the same organization, the VPN is called an Intranet. If
the sites belong to different organizations that share a common
interest, the VPN is called an Extranet.
Customers are looking for service providers to deliver data and
telecom connectivity over one or more shared networks,with service
level assurances in the form of security, QoS and other parameters.
In order to provide isolation between the traffic belonging to
different customers, mechanisms such as Layer 2 connections or Layer
2/3 tunnels are necessary. When the shared infrastructure is an IP
network, the tunneling technologies that are typically used are
IPsec, MPLS, L2TP, GRE, IP-in-IP etc.
Traditional Internet VPNs have been based on IPsec to provide
security over the Internet. Service providers are now beginning to
deploy enhanced VPN services that provide features such as service
differentiation, traffic management, Layer 2 and Layer 3
connectivity, etc. in addition to security. Newer tunneling
mechanisms have certain features that allow the service providers to
provide these enhanced VPN services.
The VPN solutions we define now must be able to accommodate the
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traditional types of VPNs as well as the enhanced services now being
deployed. They need to be able to run in a single service provider's
network, as well as between a set of service providers and across the
Internet. In doing so the VPNs should not be allowed to violate basic
Internet design principles or overload the Internet core routers or
accelarate the growths of the Internet routing tables. Specifically,
Internet core routers shall not be required to maintain VPN-related
information, regardless of whether the Internet routing protocols are
used to distribute this information or not. In order to achieve this,
the mechanisms used to develop various PPVPN solutions shall be as
common as possible with generic Internet infrastructure mechanisms
like discovery, signaling, routing and management. At the same time,
existing Internet infrastructure mechanisms shall not be overloaded.
Another generic requirement from a standardization perspective is to
limit the number of different solution approaches to a specific type
of VPN to as small a number as possible.
1.3. Outline of this document
This document describes generic requirements for Provider Provisioned
Virtual Private Networks (PPVPN). The document contains several
sections, with each set representing a significant aspect of PPVPN
requirements. Section 2 lists authors who contributed to this
document. Section 3 defines terminology and presents a taxonomy of
PPVPN technologies. The taxonomy contains two broad classes,
representing Layer 2 and Layer 3 VPNs. Each top level VPN class
contains subordinate classes. For
example, the Layer 3 VPN class contains a subordinate class of PE-
based Layer 3 VPNs. Sections 4, 5, 6 describe generic PPVPN
requirements.
The requirements are broadly classified under the following
categories:
1) Service requirements - Service attributes that the customer can
observe or measure. For example, does the service forward frames or
route datagrams? What security guarantees does the service provide?
Availability and stability are key requirements in this category.
2) Provider requirements - Characteristics that Service Providers use
to determine the cost-effectiveness of a PPVPN service. Scaling and
management are examples of Provider requirements.
3) Engineering requirements - Implementation characteristics that
make service and provider requirements achievable. These can be
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further classified as:
3a) Forwarding plane requirements - e.g., requirements related to
router forwarding behavior.
3b) Control plane requirements - e.g., requirements related to
reachability and distribution of reachability information.
3c) Requirements related to the commonality of PPVPN mechanisms with
each other and with generic Internet mechanisms.
2. Contributing Authors
This document was the combined effort of several individuals that
were part of the PPVPN requirements design team. A significant set
of requirements were directly taken from previous work by the PPVPN
WG to develop requirements for Layer 3 PPVPN [L3REQTS]. The
following are the authors that contributed to this document:
Loa Andersson
Ron Bonica
Dave McDysan
Junichi Sumimoto
Muneyoshi Suzuki
David Meyer
Marco Carugi
Yetik Serbest
Luyuan Fang
Javier Achirica
3. Definitions and Taxonomy
The terminology used in this document is defined in [TERMINOLOGY].
PPVPN
________________|__________________
| |
Layer 2 Layer 3
______|_____ ______|________
| | | |
P2P P2M PE-based CE-based
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(vpws) ____|____ ______|____ |
| | | | |
VPLS IPLS RFC2547 Virtual IPsec
Style Router
The figure above presents a taxonomy of PPVPN technologies. Some of
the definitions that are not covered in [TERMINOLOGY] are given
below:
CE-based VPN: A VPN approach in which the shared service provider
network does not have any knowledge of the customer VPN. This
information is limited to CE equipment.
PE-Based VPNs: A layer 3 VPN approach in which a service provider
network is used to interconnect customer sites using shared
resources. Specifically the PE device maintains VPN state, isolating
users of one VPN from users of another VPN. Because the PE device
maintains all required VPN state, the CE device may behave as if it
were connected to a private network. Specifically, the CE in a PE-
based VPN must not require any changes or additional functionality to
be connected to a PPVPN instead of a private network.
Virtual Router (VR) style: A PE-based VPN approach in which the PE
router maintains a complete logical router for each VPN that it
supports. Each logical router maintains a unique forwarding table
and executes a unique instance of the routing protocols. These VPNs
are described in [PPVPN-VR].
RFC 2547 Style: A PE-based VPN approach in which the PE router
maintains separate forwarding environment for each VPN and a separate
forwarding table for each VPN. In order to maintain multiple
forwarding table instances while running only a single routing
protocol instance, RFC 2547 style VPNs mark route advertisements with
attributes that identify their VPN context. These VPNs are based on
the approach described in [RFC2547bis].
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4. Service requirements
These are the requirements that a customer can observe or measure, in
order to verify if the PPVPN service that the Service Provider (SP)
provides is satisfactory.
4.1. Availability
VPN services must have high availability. VPNs that are distributed
over several sites require connectivity to be maintained even in the
event of network failures or degraded service.
This can be achieved via various redundancy techniques such as:
1. Physical Diversity
A single site connected to multiple CEs (for CE-based PPVPN) or PEs
(for PE-based PPVPNs), or different POPs, or even different service
providers
or
2. via tunnel redundancy.
4.2. Stability
In addition to availability, VPN services must also be stable.
Stability is a function of several components such as VPN routing,
signaling and discovery mechanisms, in addition to tunnel stability.
Stability of the VPN service is directly related to the stability of
the mechanisms and protocols used to establish the service. It
should also be possible to allow network upgrades and maintenance
procedures without impacting the VPN service.
4.3. Traffic types
VPN services must support unicast (or point to point) traffic and
should support any-to-any traffic including multicast and broadcast
traffic. In the broadcast model, the network delivers a stream to all
members of a subnetwork, regardless of their interest in that stream.
In the multicast model, the network delivers a stream to a set of
destinations that have registered interest in the stream. All
destinations need not belong to the same subnetwork. Multicast is
more appropriate for L3 VPNs while broadcast is more appropriate for
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L2VPNs. It is desirable to support multicast limited in scope to an
intranet or extranet. The solution should be able to support a large
number of such intranet or extranet specific ulticast groups in a
scalable manner.
A PPVPN shall support both IPv4 and IPv6 traffic.
4.4. Data isolation
The PPVPN must support forwarding plane isolation. The network must
never deliver user data accross VPN boundaries unless the two VPNs
participate in an intranet or extranet.
Furthermore, if the provider network receives signaling or routing
information from one VPN, it must not reveal that information to
another VPN unless the two VPNs participate in an intranet or
extranet.
4.5. Security
A range of security features should be supported by the suite of
PPVPN solutions in the form of securing customer flows, providing
authentication services for temporary, remote or mobile users, and
the need to protect service provider resources involved in supporting
a PPVPN[VPN SEC]. Each PPVPN solution should state which security
features it supports and how such features can be configured on a per
customer basis. Protection against Denial of Service (DoS) attacks is
a key component of security mechanisms. Examples of DoS attacks
include mail spamming, access connection congestion, TCP SYN attacks,
ping attacks and intrusion attempts such as Trojan horse attack.
4.5.1. User data security
PPVPN solutions that support user data security should use standard
methods (e.g., IPsec) to achieve confidentiality, integrity,
authentication and replay attack prevention. Such security methods
must be configurable between different end points, such as CE-CE, PE-
PE, and CE-PE. It is also desirable to configure security on a per-
route or per-VPN basis.
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4.5.2. Access control
A PPVPN solution may also have the ability to activate the
appropriate filtering capabilities upon request of a customer. A
filter provides a mechanism so that access control can be invoked at
the point(s) of communication between different organizations
involved in an extranet. Access control can be implemented by a
firewall, access control lists on routers or similar mechanisms to
apply policy-based access control to transit traffic. Access control
must also be applicable between CE-CE, PE-PE and CE-PE.
4.5.3. Site authentication and authorization
A PPVPN solution requires authentication and authorization of the
following:
- temporary and permanent access for users connecting to sites
(authentication and authorization BY the site)
- the site itself (authentication and authorization FOR the site)
4.5.4. Inter domain security
The VPN solution must have appropriate security mechanisms to prevent
the different kinds of Distributed Denial of Service (DDoS) attacks
mentioned earlier, misconfiguration or unauthorized accesses in inter
domain PPVPN connections.
4.6. Topology
A VPN should support arbitrary, customer agent defined inter-site
connectivity, ranging, for example, from hub-and-spoke, partial mesh
to full mesh topology. These can actually be different from the
topology used by the service provider. To the extent possible, a
PPVPN service should be independent of the geographic extent of the
deployment.
A VPN solution should support multiple VPNs per customer site without
requiring additional hardware resources per VPN. It should also
support a free mix of L2 and L3 VPNs per customer site.
To the extent possible, the PPVPN services should be independent of
access network technology.
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4.7. Addressing (support for private, overlapping addresses)
Each customer resource must be identified by an address that is
unique within its VPN. It need not be identified by a globally unique
address.
A VPN service shall be capable of supporting non-IP customer
addresses if it is a Layer 2 VPN (e.g., Frame Relay, ATM, Ethernet).
Support for non-IP Layer 3 addresses may be desirable in some cases,
but is beyond the scope of VPN solutions developed in the IETF, and
therefore, this document.
4.8. Quality of Service
A PPVPN shall be able to support QoS via IETF standardized mechanisms
such as Diffserv. Support for best-effort traffic shall be mandatory
for all PPVPN types.
Note that all cases involving QoS may require that the CE and/or PE
perform shaping and/or policing.
The need to provide QoS will occur primarily in the access network,
since that will often be the bottleneck. This is likely to occur
since the backbone effectively statistically multiplexes many users,
and is traffic engineerd or includes capacity for restoration and
growth. There are two directions of QoS management that must be
considered in any PPVPN service regarding QoS:
- From the CE across the access network to the PE
- From the PE across the access network to CE
PPVPN CE and PE devices should be capable of supporting QoS across at
least the following subset of access networks, although, to the
extent possible, the QoS capability of a PPVPN should be independent
of the access network technology :
- ATM Virtual Connections (VCs)
- Frame Relay Data Link Connection Identifiers (DLCIs)
- 802.1d Prioritized Ethernet
- MPLS-based access
- Multilink Multiclass PPP
- QoS-enabled wireless (e.g., LMDS, MMDS)
- Cable modem
- QoS-enabled Digital Subscriber Line (DSL)
Different service models for QoS may be supported. Examples of PPVPN
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QoS service models are:
- Managed access service : Provides QoS on the access connection
between CE and the customer facing ports of the PE. No QoS support
is required in the provider core network in this case.
- Edge-to-edge QoS : Provides QoS across the provider core, either
between CE pairs or PE pairs, depending on the tunnel demarcation
points. This scenario requires QoS support in the provider core
network.
4.9. Service Level Agreement and Service Level Specification Monitoring
and Reporting
A Service Level Specification (SLS) may be defined per access network
connection, per VPN, per VPN site, and/or per VPN route. The service
provider may define objectives and the measurement interval for at
least the SLS using the following Service Level Objective (SLO)
parameters:
- QoS and traffic parameters for the Intserv flow or Diffserv
class [Y.1541]
- Availability for the site, VPN, or access connection
- Duration of outage intervals per site, route or VPN
- Service activation interval (e.g., time to turn up a new site)
- Trouble report response time interval
- Time to repair interval
- Total traffic offered to the site, route or VPN
- Measure of non-conforming traffic for the site, route or VPN
- Delay and delay variation (jitter) bounds
- Packet ordering, at least when transporting L2 services
sensitive to reordering (e.g., ATM).
The above list contains items from [Y.1241], as well as other items
typically part of SLAs for currently deployed VPN services [FRF.13].
See [RFC3198] for generic definitions of SLS, SLA, and SLO.
The provider network management system shall measure, and report as
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necessary, whether measured performance meets or fails to meet the
above SLS objectives.
The service provider and the customer may negotiate a contractual
arrangement that includes a Service Level Agreement (SLA) regarding
compensation if the provider does not meet an SLS performance
objective. Details of such compensation are outside the scope of
this document.
4.10. Network Resource Partitioning and Sharing between VPNs
Network resources such as memory space, FIB table, bandwidth and CPU
processing shall be shared between VPNs. Mechanisms should be
provided to prevent any specific VPN from taking up available network
resources and causing others to fail.
5. Provider requirements
This section describes operational requirements for a cost-effective,
profitable VPN service offering.
5.1. Scalability
The scalability for VPN solutions has many aspects. The list below is
intended to comprise of the aspects that PPVPN solutions should
address. Clearly these aspects in absolute figures are very
different for different types of VPNs - i.e., a point to point
service has only two sites, while a VPLS or L3VPN may have a larger
number of sites. It is also important to verify that PPVPN solutions
not only scales on the high end, a VPN with three sites and three
users should be as viable as a VPN with hundreds of sites and
thousands of users.
Terminology:
Site: a geographical location with one or more users or one or more
servers or a combination of servers and users.
User: the end user equipment (hosts), e.g., a workstation.
Note: Further discussion on Section 5.1.1 and 5.1.2 is needed.
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5.1.1. Service Provider Capacity Sizing Projections
A PPVPN solution should be scalable to support a very large number of
VPNs per Service Provider network. The estimate is that a large
service provider will require support for on the order of 10,000
VPNs within four years.
A PPVPN solution should be scalable to support of a wide range of
number of site interfaces per VPN, depending on the size and/or
structure of the customer organization. The number of site
interfaces should range from a few site interfaces to over 50,000
site interfaces per VPN.
A PPVPN solution should be scalable to support of a wide range of
number of routes per VPN. The number of routes per VPN may range
from just a few to the number of routes exchanged between ISPs (on
the order of 100,000). The high end number is especially true
considering the fact that many large ISPs may provide VPN services to
smaller ISPs or large corporations. Typically, the number of routes
per VPN are twice the number of site interfaces or larger.
A PPVPN solution should support high values of the frequency of
configuration setup and change, e.g., for real-time provisioning of
an on-demand videoconferencing VPN or addition/deletion of sites.
Approaches should articulate scaling and performance limits for more
complex deployment scenarios, such as inter-AS(S) VPNs and carriers'
carrier. Approaches should also describe other dimensions of
interest, such as capacity requirements or limits, number of
interworking instances supported as well as any scalability
implications on management systems.
A PPVPN solution should support a large number of customer interfaces
on a single PE (for PE-based PPVPN) or CE (for CE-based PPVPN) with
current Internet protocols.
5.1.2. VPN Scalability aspects
This section describes the metrics for scaling PPVPN solutions,
points out some of the scaling differences between L2 and L3 VPNs.
Further discussion on service provider sizing projections are in
Section 5.1.2.
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5.1.2.1. Number of users per VPN
The number of users per VPN is the combination of servers and hosts
connected to the VPN. It needs to scale from a handful to extremely
high numbers.
Clearly there is a possible trade off between the number of users and
the VPN technology chosen.
L3 VPNs must scale from 2 users per VPN to O(10^5) users per VPN. L2
VPNs must scale from 2 users to a few hundred.
5.1.2.2. Number of users per site
The number of users per site follows the same logic as for users per
VPN. Further, it must be possible to have single user sites connected
to the same VPN as very large sites are connected to.
L3 VPNs must scale from 1 user per site to thousands of users per
site. L2 VPNs must scale from 1 user to a few hundred per site.
5.1.2.3. Number of sites per VPN
The number of sites per VPN is clearly limited by the number of users
for a L2 VPN. The largest number of sites in a L2VPN would be equal
to the largest number of users, distributed one per site. For L3 VPNs
number of sites per VPN should scale from 2 to very large numbers
that are usually limited by router memory.
5.1.2.4. Number of PEs
The number of PEs that supports the same set of VPNs, i.e., the
number of PEs that needs to directly exchange information on VPN de-
multiplexing information is clearly a scaling factor. This number is
driven by the type of VPN service, and also by whether the service is
within a single AS/domain or involves a multi-SP or multi-AS network.
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5.1.2.5. Number of sites per PE
The number of sites per PE needs to be discussed based on several
different scenarios. On the one hand there is a limitation to the
number of customer facing interfaces that the PE can support. On the
other hand the access network may aggregate several sites connected
on comparatively low bandwidth on to one single high bandwidth
interface on the PE. The scaling point here is that the PE must be
able to support a few or even a single site on the low end and
O(10^4) sites on the high end. Various PPVPN solutions may be
evaluated based on this requirement.
5.1.2.6. Number of VPNs in the network
The number of sites in a network should not be a scaling issue. The
number of VPNs should scale linearly with the size of the access
network and with the number of PEs. As mentioned in Section 5.1.1,
the number of VPNs in the network should be O(10^4).
5.1.2.7. Number of VPNs per PE
This is a function of number of sites per PE and number of VPNs per
site. It is estimated that the number of VPNs needs to be at least
one order of magnitude higher than the number of sites per PE.
5.1.2.8. Number of VPNs per site
On a customer's main site it is fully conceivable that the number of
VPNs could be fairly large, both service diversification and
separation of different work groups contributes to this. It is
possible that one customer will run up to O(100) VPNs.
5.1.2.9. Number of addresses per VPN
Since any VPN solution shall support private customer addresses, the
number of addresses supported for a L3 VPN needs to scale from very
few (for smaller customers) to very large numbers seen in typical SP
backbones. The high end is especially true considering that many Tier
1 SPs may provide VPN services to Tier 2 SPs or to large
corporations. For a L2 VPN this number would be on the order of
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addresses supported in typical native Layer 2 backbones.
5.1.2.10. Number of addresses per PE
This is a function of the number of VPNs per site and the number of
addresses per site.
5.1.3. Solution-Specific Metrics
Each PPVPN solution shall document its scalability characteristics in
quantitative terms. Two examples are provided below as an
illustration.
The following example applies to the number of tunnels necessary in
various devices in the network. In a PE-based VPN, edge-to-edge
tunnels (PE-to-PE) need to be established, while in a CE-based VPN,
end-to-end tunnels between pairs of CEs are necessary. Therefore,
fewer tunnels need to be maintained in a PE-based solution and
scalability could be improved over that of CE-based VPNs. The other
tradeoff is that in a PE-based solution, the CE is simple at the
expense of complex PE devices, while on the other hand, in a CE-
based solution, the PE devices remain simple while the CE devices are
more complex.
A scalable PE-based solution should quantify the amount of state that
a PE and P device must support. This should be stated in terms of
the total number of VPNs and site interfaces supported by the
service provider. Ideally, all VPN-specific state should be
contained in the PE device for a PE-based VPN. Similarly, all VPN-
specific state should be contained in the CE device for a CE-based
VPN. In all cases, the backbone routers (P devices) shall not
maintain VPN-specific state as far as possible.
5.2. Management
A service provider must have a means to view the topology,
operational state, order status, and other parameters associated with
each customer's VPN. Furthermore, the service provider must have a
means to view the underlying logical and physical topology,
operational state, provisioning status, and other parameters
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associated with the equipment providing the VPN service(s) to its
customers.
VPN devices should provide standards-based management interfaces
wherever feasible.
Service Provider Network Management System (NMS) requirements mainly
fall in the traditional fault, configuration, accounting,
performance, and security (FCAPS) management categories. These
requirements are available in detail in [Y.1311.1].
6. Engineering requirements
These requirements are driven by implementation characteristics that
make service and provider requirements achievable.
6.1. Forwarding plane requirements
VPN solutions should not pre-suppose or preclude the use of IETF
developed tunneling techniques such as IP-in-IP, L2TP, GRE, MPLS or
IPsec. The separation of VPN solution and tunnels will facilitate
adaptability with extensions to current tunneling techniques or
development of new tunneling techniques. It should be noted that the
choice of the tunneling techniques may impact the service
capabilities of the VPN solution.
For Layer 2 VPNs, solutions should utilize the encapsulation
techniques defined by PWE3, and should not impose any new
requirements on these techniques.
PPVPN solutions must not impose any restrictions on the backbone
traffic engineering and management techniques. Conversely, backbone
engineering and management techniques must not affect the basic
operation of a PPVPN, apart from impacting the SLA/SLS guarantees
associated with the service.
By definition, VPN traffic should be segregated from each other, and
from non-VPN traffic in the network. After all, VPNs are a means of
dividing a physical network into several logical (virtual) networks.
VPN traffic separation should be done in a scalable fashion. However,
safeguards should be made available against misbehaving VPNs to not
affect the network and other VPNs.
VPN solution should not impose any hard limit on the number of VPNs
provided in the network.
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6.2. Control plane requirements
The plug and play feature of a VPN solution with minimum
configuration requirements is an important consideration. The VPN
solutions should have mechanisms for protection against customer
interface and/or routing instabilities so that they do not impact
other customers' services.
A VPN should be provisioned with minimum number of steps. For
instance, a VPN need not be configured in every PE. For this to be
accomplished, an auto-configuration and an auto-discovery protocol,
which should be common to all VPN solutions, should be defined.
However, these mechanisms should not affect the cost, scalability or
stability of a service by being overly complex, or by increasing
layers in the protocol stack.
6.3. Control Plane Containment
The PPVPN control plane must include a mechanism through which the
service provider can filter PPVPN related control plane information
as it passes between Autonomous Systems. For example, if a service
provider supports a PPVPN offering, but the service provider's
neighbors do not participate in that offering, the service provider
should not leak PPVPN control information into neighboring networks.
Neighboring networks must be equipped with mechanisms that filter
this information should the service provider leak it.
6.4. Requirements related to commonality of PPVPN mechanisms with each
other and with generic Internet mechanisms
As far as possible, the mechanisms used to establish a VPN service
should re-use well-known IETF protocols as far as possible, limiting
the need to define new protocols from scratch. It should, however, be
noted that the use of Internet mechanisms for the establishment and
running of an Internet-based VPN service, shall not affect the
stability, robustness, and scalability of the Internet or Internet
services. In other words, these mechanisms should not conflict with
the architectural principles of the Internet, nor should it put at
risk the existing Internet systems. For example, IETF-developed
routing protocols should be used for routing of L3 PPVPN traffic,
without adding VPN-specific state to the Internet routers. Similarly,
familiar L2 technologies should be used in VPNs offering L2 services,
without imposing risks to the Internet routers. A solution must be
implementable without requiring to add additional funcionality to the
devices in a network.
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In addition to commonality with generic Internet mechanisms,
infrastructure mechanisms used in different PPVPN solutions (both L2
and L3), e.g., discovery, signaling, routing and management, should
be as common as possible.
6.5. Interoperability
Each technical solution is expected to be based on interoperable
Internet standards.
Multi-vendor interoperability at network element, network and service
levels among different implementations of the same technical solution
should be ensured (that will likely rely on the completeness of the
corresponding standard). This is a central requirement for SPs and
customers.
The technical solution must be multi-vendor interoperable not only
within the SP network infrastructure, but also with the customer's
network equipment and services making usage of the PPVPN service.
Customer access connections to a PPVPN solution may be different at
different sites (e.g., Frame Relay on one site and Ethernet on
another)
Interconnection of a L2VPN to a L3VPN as if it were a customer site
shall be supported.
Inter-domain interoperability - It should be possible to deploy a
PPVPN solution across domains, Autonomous Systems, or the Internet.
7. Security Considerations
This document does not have any security considerations other than
the security requirements described in Section 4.5.
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8. References
8.1. Normative References
[RFC2026] Bradner, S., "The Internet Standards Process - Revision
3", BCP 9, RFC 2026, October 1996.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997
8.2. Non-normative References
[TERMINOLOGY] Andersson, L., Madsen, T., "Terminology for Provider
Provisioned Virtual Private Networks", work in progress
[PPVPN-FR] Callon, R., Suzuki, M., et al. "A Framework for Provider
Provisioned Virtual Private Networks ", work in progress
[PPVPN-VR] Ould-Brahim, H., Gleeson, B., et al. "Network based IP
VPN Architecture using Virtual Routers", work in
progress
[L3REQTS] Carugi, M., McDysan, D. et al., "Service Requirements
for Layer 3 Provider Provisioned Virtual Private
Networks", work in progress
[RFC2547bis] Rosen, E., Rekhter, Y. et al., "BGP/MPLS VPNs", work
in progress.
[Y.1241] "IP Transfer Capability for the support of IP based
Services", Y.1241 ITU-T Draft Recommendation, March 2000
[Y.1311.1] Carugi, M. (editor), "Network Based IP VPN over MPLS
architecture",Y.1311.1 ITU-T Recommendation, May 2001
(http://ppvpn.francetelecom.com/ituRelated.html)
[Y.1311] Knightson, K. (editor), " Network based IP VPN Service
- Generic Framework and Service Requirements ", Y.1311
ITU-T Draft Recommendation, May 2001
(http://ppvpn.francetelecom.com/ituRelated.html)
[RFC 3198] A. Westerinen et al, "Terminology for Policy-Based
Management," November, 2001.
[VPN SEC] J. De Clercq et al, "Considerations about possible
security extensions to BGP/MPLS VPN," work in progress.
[FRF.13] Frame Relay Forum, "Service Level Definitions
Implementation Agreement," August, 1998.
[Y.1541] "Network Performance Objectives for IP-based
Services," Y.1541, ITU-T Recommendation.
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9. Acknowledgements
This work was done in consultation with the entire design team for
PPVPN requirements. A lot of the text was adapted from the Layer 3
requirements document produced by Layer 3 requirements design team.
The authors would also like to acknowledge the constructive feedback
from Alex Zinin.
10. Editor's Address
Ananth Nagarajan
Sprint
6220 Sprint Parkway
Overland Park, KS 66251
USA
E-mail: ananth.nagarajan@mail.sprint.com
11. Full Copyright Statement
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
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English.
The limited permissions granted above are perpetual and will not be
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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
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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