PPVPN Working Group Waldemar Augustyn Internet Draft Document: draft-augustyn-ppvpn-l2vpn-requirements-00.txt Giles Heron Category: Informational PacketExchange Ltd June 2002 Vach Kompella Expires: December 2002 TiMetra Networks Marc Lasserre Riverstone Networks Pascal Menezes Terabeam Hamid Ould-Brahim Nortel Networks Tissa Senevirathne Requirements for Layer 2 Virtual Private Network Services (L2VPN) Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026 [1]. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. For potential updates to the above required-text see: http://www.ietf.org/ietf/1id-guidelines.txt Augustyn, et. al. Expires December 2002 1 draft-augustyn-ppvpn-l2vpn-requirements-00.txt June 2002 Summary for Sub-IP related Internet Drafts RELATED DOCUMENTS: See references. WHERE DOES IT FIT IN THE PICTURE OF THE SUB-IP WORK This ID is intended for the PPVPN WG. WHY IS IT TARGETED AT THIS WG(s) PPVPN deals with provider provisioned VPNs. This document describes requirements for L2 Virtual Private Network Services. JUSTIFICATION This document represents the evolution of draft-ietf-ppvpn-vpls- requirements-00.txt to include requirements for Virtual Private Wire Services. 1 Abstract This draft describes service requirements for L2 Virtual Private Networks. It covers non-broadcast point to point and point to multipoint VPNs referred to as Virtual Private Wire Service (VPWS), as well as broadcast domain multipoint to multipoint VPNs referred to as Virtual Private LAN Service (VPLS). L2VPNs are a class of Provider Provisioned Virtual Private Network [2]. This draft is intended to supersede draft-ietf-ppvpn-vpls- requirements-00.txt [3]. 2 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 [4]. 3 Definitions 3.1 L2VPN A network service offered by Service Providers where packets are forwarded based on layer 2 information (such as FR, ATM, or MAC) and/or on the basis of the incoming link. The term is also used, Augustyn, et al. Expires December 2002 2 draft-augustyn-ppvpn-l2vpn-requirements-00.txt June 2002 when clear from the context, to refer to a particular instance of L2VPN service. 3.2 L2VPN System A collection of communication equipment, related protocols, and configuration elements that implements L2VPN Services. 3.3 VSI Virtual Switching Instance. A virtual layer 2 forwarding entity that is closed to a L2VPN membership. VSI forwarding can be based on MAC addresses, VLAN tags, policies, topologies, filters, QoS parameters, and other relevant information on a per L2VPN basis. 3.4 VPWS Virtual Private WAN Service, a case of L2VPN implementing a non- broadcast point to point, or point to multipoint VPN. The term is also used, when clear from the context, to refer to a particular instance of VPWS service. 3.5 VPLS Virtual Private LAN Service, a case of L2VPN service distinguished by the support of L2 broadcast. The term is also used, when clear from the context, to refer to a particular instance of VPLS service. A VPLS service allows the connection of multiple sites in a single bridged domain over a provider managed IP or MPLS network. All customer sites in the VPLS appear to be on the same LAN regardless of their location. 3.6 VPLS Domain A Layer 2 VPN that is composed of a community of interest of L2 MAC addresses and VLANs. Each VPLS Domain MAY have multiple VLANs in it. 3.7 VLAN A customer VLAN identification using some scheme such as IEEE 802.1Q tags, port configuration or any other means. A VPLS service can be extended to recognize customer VLANs as specified in 6.1 . Augustyn, et al. Expires December 2002 3 draft-augustyn-ppvpn-l2vpn-requirements-00.txt June 2002 3.8 VLAN Flooding Scope (VLAN Broadcast Domain) The scope of flooding for a given VLAN. In a VPLS service, a VLAN flooding scope is identical to the flooding scope of the VPLS it is part of. If a VPLS service is extended to recognize customer VLANs, the VLAN flooding scope is limited to the broadcast domain of each recognized VLAN. 4 Introduction This document describes the service requirements for Layer 2 Virtual Private Networks. 4.1 The context of provider provisioned service The context of provider provisioned VPNs is an important factor in the structure and scope of the requirements. This context brings attention to the fact that there are two entities involved in operation of such services, the Provider and the Customer. The Provider engages in a binding agreement with the Customer as to the behavior of the service in normal situation as well as exceptional situations. Such agreement is known as Service Level Agreement (SLA). A proper design of L2 VPNs aids formulation of SLAs in that it provides means for proper separation between CE/PE, allows proper execution of the SLA offer, and supports flexible and rich set of capabilities. 4.2 L2VPN taxonomy The requirements distinguish two major L2VPNs models, a Virtual Private Wire Service (VPWS), and a Virtual Private LAN Service (VPLS). The VPWS model is simpler than VPLS and its requirements are a subset of those for VPLS. The document generally refers to L2VPN requirements which are applicable to both VPWS and VPLS. The additional requirements for VPLS are clearly stated as such. 4.2.1 Virtual Private Wire Service By far the most widely deployed are point to point VPNs. A point to point VPN behaves like a circuit terminated by a Customer Equipment (CE) at each end. This type of L2VPN service is referred to as Virtual Private Wire Service, VPWS. Augustyn, et al. Expires December 2002 4 draft-augustyn-ppvpn-l2vpn-requirements-00.txt June 2002 A variation of that service is a point to multipoint, non-broadcast L2VPN. It differs only slightly from a more common point to point VPN by offering more than one end point. The behavior of the VPN, however, remains point to point by nature. The topology of such VPNs can be fully meshed or partially meshed. In the latter case, certain CEs, spokes of a hub, will see the VPN as a point to point circuit. The VPN does not support broadcast and does not attempt to interpret broadcast addresses. It is the responsibility of a CE device to replicate packets in case broadcast emulation is desirable. 4.2.2 Virtual Private LAN Service The VPLS service attempts to emulate a broadcast domain, LAN-like, behavior for the members of the VPN. The VPN provides the capability to replicate packets and to interpret broadcast and multicast addresses according to their meaning. 5 L2VPN Reference Model The following diagram shows a L2VPN reference model where PE devices provide a logical interconnect such that CE devices belonging to a specific L2VPN appear to be connected by a single logical switching instance. +-----+ +-----+ + CE1 +--+ +---| CE2 | +-----+ | ........................ | +-----+ L2VPN A | +----+ +----+ | L2VPN A +--| PE |--- Service ---| PE |--+ +----+ Provider +----+ / . Backbone . \ - /\-_ +-----+ / . | . \ / \ / \ +-----+ + CE4 +--+ . | . +--\ Access \----| CE5 | +-----+ . +----+ . | Network | +-----+ L2VPN B .........| PE |......... \ / L2VPN B +----+ ^ ------- | | | | +-----+ | | CE3 | +-- Logical switching instance +-----+ L2VPN A 5.1 Point to point L2VPN The PE devices provide a logical interconnect such that a pair of CE devices appear to be connected by a single logical L2 circuit. Augustyn, et al. Expires December 2002 5 draft-augustyn-ppvpn-l2vpn-requirements-00.txt June 2002 PE devices maintain separate L2VPN domains for each logical L2 circuit. Such domains are then mapped onto tunnels in the service provider network. These tunnels can either be specific to a particular L2VPN, or shared among several L2VPNs (e.g. as with MPLS tunnel LSPs). In the above diagram, L2VPN B represents a point to point case. The CE-to-PE links can either be direct physical links, e.g. 100BaseTX, or logical links, e.g. ATM PVC, T1/E1 TDM, or RFC1490- encapsulated link, over which L2 traffic is carried. The flavor of the CE-PE L2 link is typically the same on each end, but it can be different in case a proper interworking is provided e.g. ATM/FR interworking, ARP mediation, or similar. The PE-to-PE links carry tunneled L2 frames using different tunneling technologies (e.g., GRE, IPSec, MPLS, L2TP, etc.). Each PE device is responsible for allocating customer L2 frames to the appropriate L2VPN and for proper forwarding to the intended end nodes. 5.2 Point to multipoint, non-broadcast L2VPN A non-broadcast point to multipoint L2VPN behaves similarly to a point to point L2VPN. It differs in that there is more than one L2 destination reachable via a L2VPN instance. To the CE, it looks like a collection of point to point circuits. The VPN does not provide for packet replication, nor does it recognize broadcast addresses. A CE can emulate broadcast by explicit replication by each CE. In the diagram above, L2VPN A can represent a point to multipoint L2VPN. The L2VPN topology for the customer devices, CE1, CE2, and CE3 can be hub and spoke or a full mesh. In the latter case, the connectivity is frequently referred to as multipoint to multipoint. 5.3 VPLS In case of VPLS, the PE devices provide a logical interconnect such that CE devices belonging to a specific VPLS appear to be connected by a single logical Ethernet bridge. A VPLS can contain a single VLAN or multiple, tagged VLANs. Separate L2 broadcast domains are maintained on a per VPLS basis by PE devices. Such domains are then mapped onto tunnels in the service provider network. These tunnels can either be specific to a VPLS (e.g. as with IP) or shared among several VPLSs (e.g. as with MPLS tunnel LSPs). In the above diagram, the top PE routers maintain separate forwarding instances for VPLS A and VPLS B. Augustyn, et al. Expires December 2002 6 draft-augustyn-ppvpn-l2vpn-requirements-00.txt June 2002 The CE-to-PE links can either be direct physical links, e.g. 100BaseTX, or logical links, e.g. ATM PVC, T1/E1 TDM, or RFC1490- encapsulated link, over which bridged Ethernet traffic is carried. The PE-to-PE links carry tunneled Ethernet frames using different tunneling technologies (e.g., GRE, IPSec, MPLS, L2TP, etc.). Each PE device learns remote MAC addresses, and is responsible for proper forwarding of the customer traffic to the appropriate end nodes. It is responsible for guaranteeing each VPLS topology is loop free. 6 VPLS General Requirements 6.1 Layer 2 Domain representation A L2VPN system MUST distinguish different customer domains. Each of these customer domains MUST appear as a L2 network. For the customer devices, the L2VPN domain SHOULD behave like a native L2 network implied by the selected L2 protocol. For example, if a CE connects to a L2VPN via a FR circuit, it should expect the behavior of the VPN be similar to a connection to a true FR switch. A L2VPN MAY span multiple service providers. Each L2VPN MUST carry a unique identification within a L2VPN system. It is RECOMMENDED that L2VPN identification be globally unique. A provider's implementation of a L2VPN system SHOULD NOT constrain the customer's ability to configure VPN topologies, or Layer 2 parameters related to the supported L2 protocol. In case of VPLS, each domain MUST be capable of learning and forwarding based on MAC addresses thus emulating an Ethernet virtual switch to the customer CE devices attached to PEs. A VPLS system MAY recognize customer VLAN identification. In that case, a VLAN MUST be recognized in the context of the VPLS it is part of. If customer VLANs are recognized, separate VLAN broadcast domains SHOULD be maintained. 6.2 L2VPN Topology The L2VPN system MAY be realized using one or more network tunnel topologies to interconnect PEs, ranging from simple point-to-point to distributed hierarchical arrangements. The typical topologies include: o point-to-point Augustyn, et al. Expires December 2002 7 draft-augustyn-ppvpn-l2vpn-requirements-00.txt June 2002 o point-to-multipoint, a.k.a. hub and spoke o any-to-any, a.k.a. full mesh o mixed, a.k.a. partial mesh o hierarchical Regardless of the topology employed, the service to the customers MUST retain the connectivity type implied by the type of L2VPN. For example, a non-broadcast point to multipoint VPN should allow point to multipoint VPN connectivity even if implemented with point to point circuits. This requirement does not imply that all traffic characteristics (such as bandwidth, QoS, delay, etc.) be necessarily the same between any two end points of a L2VPN. 6.3 Redundancy and Failure Recovery The L2VPN infrastructure SHOULD provide redundant paths to assure high availability. The reaction to failures SHOULD result in an attempt to restore the service using alternative paths. The intention is to keep the restoration time small. It is RECOMMENDED that the restoration time be less than the time it takes the CE devices to detect a failure in the L2VPN. In cases where the provider knows a priori about impending changes in network topology, the network SHOULD have the capability to reconfigure without a loss, duplication, or re-ordering of customer packets. This situation typically arises with planned network upgrades or scheduled maintenance activities. 6.4 Policy Constraints A L2VPN system MAY employ policy constraints governing various interconnection attributes for L2VPN domains. Typical attributes include: o Selection of available network infrastructure o QoS services needed o Protection services needed o Availability of higher level service access points (see 9.7 ) Policy attributes SHOULD be advertised via the L2VPN system's control plane. 6.5 PE nodes The PE nodes are the devices in the L2VPN system that store information related to customer L2VPN domains and employ methods to forward customer traffic based on that information. In this document, the PE nodes are meant in logical sense. In the actual Augustyn, et al. Expires December 2002 8 draft-augustyn-ppvpn-l2vpn-requirements-00.txt June 2002 implementations, the PE nodes may be comprised of several physical devices. Conversely, a single physical device may contain more than one PE node. All forwarding decisions related to customer L2VPN traffic MUST be made by PE nodes. This requirement prohibits any other network components from altering decisions made by PE nodes. 6.6 PE-PE Interconnection and Tunneling A L2VPN system MUST provide for connectivity between each pair of PE nodes. The connectivity is referred to as transport tunneling or simply tunneling. There are several choices for implementing transport tunnels. Some popular choices include MPLS, IP in IP tunnels, variations of 802.1Q, etc. Regardless of the choice, the existence of the tunnels and their operations MUST be transparent to the customers. 6.7 PE-CE Interconnection and Profiles A L2VPN system MUST provide for connectivity between PE nodes and CE nodes. That connectivity is referred to as CE access connection, access connection, or simply access. Access connections MAY span networks of other providers or public networks. There are several choices for implementing access. Some popular choices include Ethernet, ATM (DSL), Frame Relay, MPLS-based virtual circuits etc. In case of VPLS, the access connection MUST use Ethernet frames as the Service Protocol Data Unit (SPDU). A CE access connection MUST be bi-directional in nature. PE devices MAY support multiple CE access connections on a single physical interface. In such cases, PE devices MUST NOT rely on customer controlled parameters, such as VLAN tags etc., for distinguishing between different access connections. A CE access connection, whether direct or virtual, MUST maintain all committed characteristics of the customer traffic, such as QoS, priorities etc. The characteristics of a CE access connection are only applicable to that connection. 7 Control Plane Requirements 7.1 Provider Edge Signaling Augustyn, et al. Expires December 2002 9 draft-augustyn-ppvpn-l2vpn-requirements-00.txt June 2002 The control protocols SHOULD provide methods for signaling between PEs. The signaling SHOULD inform of membership, tunneling information, and other relevant parameters. The infrastructure MAY employ manual configuration methods to provide this type of information. The infrastructure SHOULD use policies to scope the membership and reachability advertisements for a particular L2VPN. 7.2 L2VPN Membership Discovery The control protocols SHOULD provide methods to discover the PEs which connect CEs forming a L2VPN. 7.3 Support for Layer 2 control protocols A L2VPN system MUST ensure that loops be prevented. This can be accomplished through a loop free topologies or appropriate forwarding rules. In case of VPLS, control protocols such as Spanning Tree or similar could be employed. The L2VPN system's control protocols SHOULD allow transparent operation of Layer 2 control protocols employed by customers. In case of VPLS, a VPLS system's control protocols MAY use indications from customer STP to improve the operation of a VPLS. 7.4 Scaling Requirements In a L2VPN system, the control plane traffic increases with the growth of L2VPN membership. Similarly, the control plane traffic increases with the number of supported L2VPN domains. The rate of growth of the associated control plane traffic SHOULD be linear. The use of control plane resources increases with the number of hosts connected to a L2VPN grows. The rate of growth of the demand for control process resources SHOULD be linear. The control plane MAY offer means for enforcing a limit on the number of customer hosts attached to a L2VPN. 8 Data Plane Requirements 8.1 Transparency Augustyn, et al. Expires December 2002 10 draft-augustyn-ppvpn-l2vpn-requirements-00.txt June 2002 L2VPN service is intended to be transparent to Layer 2 customer networks. It SHOULD NOT require any special packet processing by the end users before sending packets to the provider's network. 8.2 Layer 2 Virtual Switching Instance L2VPN Provider Edge devices MUST maintain a separate Virtual Switching Instance (VSI) per each VPN. Each VSI MUST have capabilities to forward traffic based on customer's traffic parameters such as DLCI, VPI/VCI, MAC addresses, VLAN tags (if supported), etc. as well as local policies. L2VPN Provider Edge devices MUST have capabilities to classify incoming customer traffic into the appropriate VSI. In case of VPLS, Each VSI MUST have flooding capabilities for its Broadcast Domain to facilitate proper forwarding of Broadcast, Multicast and Unknown Unicast customer traffic. 8.3 Minimum MTU The L2VPN service MUST support customer frames with payload 1500 bytes long. The service MAY offer support for longer frames. The service MUST NOT fragment packets. Packets exceeding committed MTU size MUST be discarded. The committed minimum MTU size MUST be the same for a given instance of L2VPN. Different L2VPN instances MAY have different committed MTU sizes. In case of VPLS, if VLANs are supported, all VLANs within a given VPLS MUST inherit the same MTU size. 8.4 QoS and packet re-ordering A L2VPN system SHOULD have capabilities to enforce QoS parameters. The queuing and forwarding policies SHOULD preserve packet order for packets with the same QoS parameters. The service SHOULD not duplicate packets. 8.5 Additional requirements for VPLS systems 8.5.1 Broadcast Domain Augustyn, et al. Expires December 2002 11 draft-augustyn-ppvpn-l2vpn-requirements-00.txt June 2002 The Broadcast Domain is defined as the flooding scope of a Layer 2 network. A separate Broadcast Domain MUST be maintained for each VPLS. In addition to VPLS Broadcast Domains, a VPLS system MAY recognize customer VLAN Broadcast Domains. In that case, the system SHOULD maintain a separate VLAN Broadcast Domain for each customer VLAN. A VLAN Broadcast Domain MUST be a subset of the owning VPLS Broadcast Domain. 8.5.2 MAC address learning A VPLS service SHOULD derive all topology and forwarding information from packets originating at customer sites. Typically, MAC addresses learning mechanisms are used for this purpose. In a VPLS system, MAC address learning MUST take place on a per Virtual Switching Instance (VSI) basis, i.e. in the context of a VPLS and, if supported, in the context of VLANs therein. 8.5.3 Unicast, Unknown Unicast, Multicast, and Broadcast forwarding VPLS MUST be aware of the existence and the designated roles of special MAC addresses such as Multicast and Broadcast addresses. VPLS MUST forward these packets according to their intended functional meaning and scope. Broadcast packets MUST be flooded to all destinations. Multicast packets MUST be flooded to all destinations. However, a VPLS system MAY employ multicast snooping techniques, in which case multicast packets SHOULD be forwarded only to their intended destinations. Unicast packets MUST be forwarded to their intended destinations. Unknown Unicast packets MUST be flooded to all destinations in the flooding scope of the VPLS (or VLAN). If the VPLS service relies on MAC learning for its operations, it MUST assure proper forwarding of packets with MAC addresses that have not been learned. Once destination MAC addresses are learned, unicast packets SHOULD be forwarded only to their intended destinations. A provider MAY employ a method to limit the scope of flooding of Unknown Unicast packets in cases where a customer desires to conserve its bandwidth or wants to implement certain security policies. Augustyn, et al. Expires December 2002 12 draft-augustyn-ppvpn-l2vpn-requirements-00.txt June 2002 8.5.4 Multilink Access The VPLS service SHOULD support multilink access for CE devices. The VPLS service MAY support multihome access for CE devices. 8.5.5 End-point VLAN tag translation If VLANs are recognized, the VPLS system MAY support translation of customers' VLAN tags. Such service simplifies connectivity of sites that want to keep their tag assignments or sites that belong to different administrative entities. In the latter case, the connectivity is sometimes referred to as L2 extranet. 8.5.6 Support for MAC Services VPLS are REQUIRED to provide MAC service compliant with IEEE 802.1D specification [5] Section 6. Compliance with this section facilitates proper operation of 802.1 LAN and seamless integration of VPLS with bridged Local Area Networks. It is also useful to compare [6], [7], and [8]. A MAC service in the context of VPLS is defined as the transfer of user data between source and destination end stations via the service access points using the information specified in the VSI. 1. A PE device that provides VPLS MUST NOT be directly accessed by end stations except for explicit management purposes. 2. All MAC addresses MUST be unique within a given broadcast domain. 3. The topology and configuration of the VPLS MUST NOT restrict the MAC addresses of end stations 9 Management and Operations Requirements 9.1 L2VPN configuration and monitoring A L2VPN system MUST have capabilities to configure, manage, and monitor its different components. It SHOULD be possible to create several disjoint instances of L2VPN systems within the same underlying network infrastructures. The infrastructure SHOULD monitor all characteristics of the service that are reflected in the customer SLA. This includes but is not limited to bandwidth usage, packet counts, packet drops, service outages, etc. Augustyn, et al. Expires December 2002 13 draft-augustyn-ppvpn-l2vpn-requirements-00.txt June 2002 9.2 L2VPN operations The operations of a L2VPN systems is controlled by an administrative authority, or admin. The admin is the originator of all operational parameters of a L2VPN system. Conversely, the admin is also the ultimate destination for the status of the L2VPN system and the related statistical information. A typical L2VPN system spans several such admins. A L2VPN system MUST support proper dissemination of operational parameters to all elements of a L2VPN system in the presence of multiple admins. A L2VPN system MUST employ mechanisms for sharing operational parameters between different admins. These mechanism MUST NOT assume any particular structure of the different admins. For example the L2VPN should not be relying on admins forming a hierarchy. A L2VPN system SHOULD support policies for proper selection of operational parameters coming from different admins. Similarly, a L2VPN system SHOULD support policies for selecting information to be disseminated to different admins. A L2VPN system SHOULD employ discovery mechanisms to minimize the amount of operational information maintained by the admins. For example, if an admin adds or removes a customer port on a given PE, the remaining PEs should determine the necessary actions to take without the admins having to explicitly reconfigure those PEs. 9.3 CE Provisioning The L2VPN MUST require only minimal or no configuration on the CE devices, depending on the CE device that connects into the infrastructure. 9.4 Customer traffic policing The L2VPN service SHOULD provide the ability to police and/or shape customer traffic entering and leaving the L2VPN system. 9.5 Dynamic Service Signaling A Provider MAY offer to Customers an in-band method for selecting services from the list specified in the SLA. A Provider MAY use the same mechanism for reporting statistical data related to the service. Augustyn, et al. Expires December 2002 14 draft-augustyn-ppvpn-l2vpn-requirements-00.txt June 2002 9.6 Class of Service Model The L2VPN service MAY define a graded selection of classes of traffic. These include, but are not limited to o range of priorities o best effort vs. guaranteed effort o range of minimum delay characteristics 9.7 L3, and higher, service access point. The L2VPN service SHOULD allow for a Provider based Service Access Point for orderly injection of L3 or higher services to the customers' VPLS segments. In particular, the L2VPN system SHOULD allow to build L3VPN services, including L3 interworking schemes such as ARP mediation or similar, over its L2VPNs. As a value added service, a Provider MAY offer access to other services such as, IP gateways, storage networks, content delivery etc. 9.8 Testing The L2VPN service SHOULD provide the ability to test and verify operational and maintenance activities on a per L2VPN basis, and in case of VPLS, on a per VLAN basis. 9.9 Learning information from customer devices The L2VPN service SHOULD provide means for limiting the amount of information learned from customer devices. For example, VPLS implementations typically limit the number of MAC addresses learned from the customers' devices. 10 Security Requirements 10.1 Traffic separation L2VPN system MUST provide traffic separation between different L2VPN domains. In case of VPLS, if VLANs are supported, the system MUST provide traffic separation between customer VLANs within each VPLS domain. Augustyn, et al. Expires December 2002 15 draft-augustyn-ppvpn-l2vpn-requirements-00.txt June 2002 10.2 Provider network protection. The L2VPN system MUST be immune to malformed or maliciously constructed customer traffic. This includes but is not limited to duplicate or invalid L2 addresses, short/long packets, spoofed management packets, spoofed VLAN tags, high volume traffic, etc. Additionally, L2VPN system MUST be immune to misconfigured or maliciously set up customer network topologies. These include customer side loops, backdoor links between sites, etc. The L2VPN infrastructure devices MUST NOT be accessible from the L2VPN. 10.3 Value added security services Value added security services such as encryption and/or authentication of customer packets, certificate management, and similar are OPTIONAL. Security measures employed by the L2VPN system SHOULD NOT restrict implementation of customer based security add-ons. 11 References 1. Bradner, S., "The Internet Standards Process -- Revision 3", BCP 9, RFC 2026, October 1996. 2. Carugi, et al., "Service requirements for Provider Provisioned Virtual Private Networks ", Work in progress, December 2001. 3. Augustyn, et al., "Requirements for Virtual Private LAN Services (VPLS)", Work in progress, March 2002. 4. Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 5. IEEE Standard 802.1Q, "IEEE Standards for Local and Metropolitan Area Networks: Virtual Bridged Local Area Networks", 1998. 6. IEEE Standard 802.1Q, "IEEE Standards for Local and Metropolitan Area Networks: Virtual Bridged Local Area Networks", 1998. 7. IEEE Standard 802.1u-2001, "IEEE Standard for Local and Metropolitan Area Networks: Virtual Bridged Local Area Networks - Amendment 1: Technical and editorial corrections", 2001. Augustyn, et al. Expires December 2002 16 draft-augustyn-ppvpn-l2vpn-requirements-00.txt June 2002 8. IEEE Standard 802.1v-2001, "IEEE Standard for Local and Metropolitan Area Networks: Virtual Bridged Local Area Networks - Amendment 2: VLAN Classification by Protocol and Port", 2001. 12 Acknowledgments We would like to acknowledge extensive comments provided by Loa Anderson, Joel Halpern, and Eric Rosen. The authors, also, wish to extend appreciations to their respective employers and various other people who volunteered to review this work and provided feedback. 13 Authors' Addresses Waldemar Augustyn Email: waldemar@nxp.com Giles Heron PacketExchange Ltd. The Truman Brewery 91 Brick Lane London E1 6QL United Kingdom Email: giles@packetexchange.net Vach Kompella TiMetra Networks 274 Ferguson Dr. Mountain View, CA 94043 Email: vkompella@timetra.com Marc Lasserre Riverstone Networks 5200 Great America Pkwy Santa Clara, CA 95054 Phone: 408-878-6500 Email: marc@riverstonenet.com Pascal Menezes Terabeam Phone: 206-686-2001 Email: pascal.menezes@terabeam.com Augustyn, et al. Expires December 2002 17 draft-augustyn-ppvpn-l2vpn-requirements-00.txt June 2002 Hamid Ould-Brahim Nortel Networks P.O. Box 3511 Station C Ottawa ON K1Y 4H7 Canada Phone: 613-765-3418 Email: hbrahim@nortelnetworks.com Tissa Senevirathne Email: tsenevir@hotmail.com Full Copyright Statement "Copyright (C) The Internet Society (2001). 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 followed, or as required to translate it into languages other than 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 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING 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." Augustyn, et al. Expires December 2002 18