Network Working Group F. Templin, Ed. Internet-Draft Boeing Research & Technology Intended status: Informational April 28, 2010 Expires: October 30, 2010 The Internet Routing Overlay Network (IRON) draft-templin-iron-01.txt Abstract The Internet routing system is experiencing a growth profile that has led many to express concerns for unsustainable routing scaling. Operational practices such as increased use of multihoming with IPv4 Provider-Independent (PI) addressing are resulting in more and more fine-grained prefixes injected into the routing system from more and more end user networks. Furthermore, depletion of the remaining public IPv4 address space has raised concerns for both increased deaggregation (leading to yet further routing scaling) and an impending address space runout scenario. At the same time, the IPv6 routing system is finally beginning to see significant growth in IPv6 Provider-Aggregated (PA) prefixes but there does not seem to be solution on the near term horizon for IPv6 PI addressing. Since the Internet must continue to support escalating growth due to increasing demand, it is clear that current mechanisms and operational practices are reaching a tipping point where something must be done. This document proposes an Internet Routing Overlay Network (IRON) for supporting sustainable growth while requiring no changes to end systems and no changes to the existing routing system. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on October 30, 2010. Copyright Notice Templin Expires October 30, 2010 [Page 1] Internet-Draft IRON April 2010 Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. IRON Routers . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. The Internet Routing Overlay Network (IRON) . . . . . . . . . 5 4. IRON Initialization . . . . . . . . . . . . . . . . . . . . . 6 4.1. IR(VP) and IR(GW) Initialization . . . . . . . . . . . . . 6 4.2. IR(EP) Initialization . . . . . . . . . . . . . . . . . . 7 5. IRON Operation . . . . . . . . . . . . . . . . . . . . . . . . 8 5.1. IR(EP) Operation . . . . . . . . . . . . . . . . . . . . . 8 5.2. IR(VP) Operation . . . . . . . . . . . . . . . . . . . . . 9 5.3. IR(GW) Operation . . . . . . . . . . . . . . . . . . . . . 10 5.4. IRON Example Configuration and Scenario . . . . . . . . . 10 6. Related Initiatives . . . . . . . . . . . . . . . . . . . . . 11 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 8. Security Considerations . . . . . . . . . . . . . . . . . . . 12 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 10.1. Normative References . . . . . . . . . . . . . . . . . . . 12 10.2. Informative References . . . . . . . . . . . . . . . . . . 12 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 13 Templin Expires October 30, 2010 [Page 2] Internet-Draft IRON April 2010 1. Introduction The Internet routing system is experiencing a growth profile that has led many to express concerns for unsustainable routing scaling. Operational practices such as increased use of multihoming with IPv4 Provider-Independent (PI) addressing are resulting in more and more fine-grained prefixes injected into the routing system from more and more end user networks. Furthermore, depletion of the remaining public IPv4 address space has raised concerns for both increased deaggregation (leading to yet further routing scaling) and an impending address space runout scenario. At the same time, the IPv6 routing system is finally beginning to see significant growth in IPv6 Provider-Aggregated (PA) prefixes but there does not seem to be solution on the near term horizon for IPv6 PI addressing. Since the Internet must continue to support escalating growth due to increasing demand, it is clear that current mechanisms and operational practices are reaching a tipping point where something must be done. Virtual Aggregation (VA) [I-D.ietf-grow-va] and Aggregation in Increasing Scopes (AIS) [I-D.zhang-evolution] are global routing proposals that introduce routing overlays using Virtual Prefixes (VPs) to reduce router Forwarding Information Base (FIB) and Routing Information Base (RIB) scaling. Routing and Addressing in Networks with Global Enterprise Recursion (RANGER) [I-D.templin-ranger] examines recursive arrangements of enterprise networks that can apply to a very broad set of use case scenarios [I-D.russert-rangers]. In particular, RANGER supports encapsulation and secure redirection by treating each layer in the recursive hierarchy as a virtual non- broadcast, multiple access "link". RANGER is an architectural framework that includes Virtual Enterprise Traversal (VET) [I-D.templin-intarea-vet] and the Subnetwork Adaptation and Encapsulation Layer (SEAL) [I-D.templin-intarea-seal] as its functional building blocks. This document proposes an Internet Routing Overlay Network (IRON) for supporting sustainable growth while requiring no changes to the existing routing system. IRON borrows concepts from VA, AIS and RANGER, and further borrows concepts from the Internet Vastly Improved Plumbing (Ivip) [I-D.whittle-ivip-arch] architecture proposal. IRON specifically seeks to enable scalable Provider- Independent (PI) addressing without changing the current BGP routing system in any way. IRON uses the IPv4 and IPv6 Internet DFZs as routing infrastructures for tunneling outer IPv4 or IPv6 packets with Routing LOCator (RLOC) addresses which encapsulate inner packets with Endpoint Interface iDentifier (EID) addresses. Moreover, inner packets can be either IPv4 or IPv6 without regard to the address family used in the outer Templin Expires October 30, 2010 [Page 3] Internet-Draft IRON April 2010 packet, and inner packets can even be non-IP protocols such as OSI. The following sections discuss details of the IRON architecture. 2. IRON Routers IRON introduces a new class of routers called IRON Routers (IRs). These routers can be simple commodity hardware platforms that are introduced incrementally, and without affecting existing infrastructure. The purpose of these new IRs is to provide waypoints (or "cairns") for navigating the IRON so that packets with Endpoint Interface iDentifier (EID) destination addresses can be delivered to the correct End User Networks (EUNs) through the use of encapsulation with minimum path stretch for initial packets and optimized routes for most packets. The different categories of IRs includes: o IR - an IRON Router of any kind o IR(VP) - a tunnel endpoint router that is owned by a VP company and that aggregates Virtual Prefixes (VP) which it sub-delegates to EUNs. An IR(VP) will typically be a commodity hardware platform with a minimum of one interface connected to the public Internet. (For example, a typical IR(VP) can be a single- interface "router on a stick".) o IR(S_VP) - an IR(VP) that forwards packets received from an IR(S_EP) to an IR(D_VP) in another VP company's network, to an IR(D_EP) in a customer EUN or to the public Internet.. o IR(D_VP) - an IR(VP) that forwards packets received from an IR(S_VP) to an IR(D_EP) and returns an encapsulated redirect message to inform the IR(S_VP) of a better next hop (i.e., the IR(D_EP) itself). o IR(EP) - a tunnel endpoint router (or host) that receives an EID Prefix (EP) from a VP company, and that connects an EUN to the IRON. An IR(EP) will typically be a customer premises equipment (CPE) device that connects the EUN to its provider(s), but may also be a router or even a singleton host within the EUN. o IR(S_EP) - an IR(EP) that forwards packets received from an end system in the EUN. IR(S_EPs) forward initial encapsulated packets to IR(S_VP)s, and thereafter may send packets directly to IR(D_EPs) if redirected to do so. o IR(D_EP) - an IR(EP) that decapsulates packets originating from an IR(D_VP) or an IR(S_EP) and forwards them to end systems in the EUN. Templin Expires October 30, 2010 [Page 4] Internet-Draft IRON April 2010 o IR(GW) - a router that acts as a gateway between the IRON and the non-IRON Internet. Each VP company configures one or more IR(GWs) which advertise the company's VPs into the Internet DFZ. An IR(GW) may be configured on the same physical platform as IR(VPs), or as a separate standalone platform. An IR(GW) will typically be a BGP router that is capable of sourcing encapsulated packets. IRON observes the Internet Protocol standards [RFC0791][RFC2460]. Other network layer protocols that can be encapsulated within IP packets are also within scope. 3. The Internet Routing Overlay Network (IRON) The Internet Routing Overlay Network (IRON) consists of IRON Routers (IRs) that use Virtual Enterprise Traversal (VET) and the Subnetwork Encapsulation and Adaptation Layer (SEAL) for the purpose of forwarding EID-addressed data packets over the IPv4 and IPv6 Internet. Each such IR views the IPv4 and IPv6 global Internets as monolithic NBMA links, and connects to the links via a VET interface used for automatic tunneling. Each IR therefore sees all other IRs as virtual single-hop neighbors on the link from the standpoint of the inner network layer protocol, while they may be separated by many physical outer IP hops. IRs are deployed incrementally and without disturbing the existing Internet routing system. The IRON is manifested through a business model in which Virtual Prefix (VP) companies own and manage a set of IR(VPs) that are dispersed throughout the Internet and that serve a set of highly- aggregated VPs. Each VP company sets up a service in which it leases EID Prefixes (EPs) taken from the VPs to customer EUNs. These EUNs may be located on the same network as the VP company's IR(VP) routers, or they may be located elsewhere within the Internet. The VP company acts as a virtual enterprise network which EUNs loosely consider as their "home" network even though they may physically arrange for basic connectivity via one or more Internet Service Provider (ISP) networks that may have no affiliation with the VP company. VP companies can therefore open for business and begin serving their customers immediately without the need to coordinate their activities with ISPs or with other VP companies. Each VP company also establishes a set of IR(GW) routers that connect to the IPv4 and/or IPv6 Internet DFZs (i.e., the IR(GW) must be a BGP router). The IR(GW) advertises all of the VP company's IPv4 VPs into the IPv4 DFZ and advertises all of its IPv6 VPs into the IPv6 DFZ. The IR(GW) forwards any EID-addressed packets coming from the DFZ to an IR(VP) that can encapsulate the packet and forward it to the appropriate IR(EP). In this way, end systems that use ISP-aggregated Templin Expires October 30, 2010 [Page 5] Internet-Draft IRON April 2010 addresses can communicate with other end systems that use IRON VP- aggregated addresses. EUNs establish at least one IR(EP) that connects the EUN to the IRON. The IR(EP) uses encapsulation to forward packets with EP source addresses to an IR(VP) belonging to its VP company as a default router. The VP company's IR(VP) then forwards the packets toward their final destination, and returns a SEAL Control Message Protocol (SCMP) redirect message to inform the IR(EP) of a better next hop if necessary. In this way, IR(EPs) experience reasonable path stretch for initial packets and can discover route-optimized paths for subsequent packets. 4. IRON Initialization IRON initialization entails the startup actions of VP company and EUN equipment The following sections discuss these startups procedures: 4.1. IR(VP) and IR(GW) Initialization Upon startup, each IR(VP) and IR(GW) owned by the VP company discovers the full set of VPs for the IRON. These VPs may be IPv4 or IPv6, but they may also be prefixes of other network layer protocols such as OSI NSAP [RFC4548], etc. Each VP is maintained in a Master VP (MVP) flat file that consists of the union of all VPs in the IRON. The MVP file is maintained by a globally-managed assigned numbers authority in exactly the same manner as the Internet Assigned Numbers Authority (IANA) currently maintains the master list of all top-level IPv4 and IPv6 delegations. Indeed, the IANA is proposed as the primary registration authority for the MVP file. Each VP in the MVP file is encoded as the tuple: "{address family, prefix/length, FQDN}", where: o "address family" is one of IPv4, IPv6, OSI/CLNP, etc. o "prefix/length" is the VP and its associated length, e.g., 2002: DB8::/32 (IPv6), 192.2/16 (IPv4), etc. o FQDN is a DNS Fully-Qualified Domain Name Each IR(VP) and IR(GW) reads the MVP from a nearby server upon startup time, and periodically checks for deltas on the server since the MVP was last read. (The MVP can be replicated across multiple servers for load balancing much in the same way that FTP mirror sites are used to manage software distributions.) Upon reading the MVP, the IR(VP/GW) resolves the FQDN corresponding to each VP into a list of DNS Well-Known Service (WKS) resource records with an IRON- Templin Expires October 30, 2010 [Page 6] Internet-Draft IRON April 2010 specific format (to be specified) that includes the address family, RLOC address, and geographic (Latitude/Longitude) coordinates at which the IR(VP) is physically located. Each RLOC address is an IPv4 or IPv6 RLOC address of an IR(VP) within the DFZ. For each VP, the IR(VP/GW) sorts the list of RLOCs in order of "geographic closeness", and inserts each "VP->RLOC" mapping into its Forwarding Information Base (FIB) with a priority corresponding to geographic closeness. Specifically, the FIB entries must be configured such that packets with destination addresses covered by the VP are forwarded to the corresponding RLOC using encapsulation of the inner network layer packet in an outer IP header. Note that the VP and RLOC may be of different address families; hence, possible encapsulations include IPv6-in-IPv4, IPv4-in-IPv6, IPv6-in-IPv6, IPv4-in-IPv4, OSI/CLNP-in-IPv6, OSI/CLNP-in-IPv4, etc. After each IR(VP/GW) reads in the list of VPs and sorts the information accordingly, it is said to be "synchronized with the IRON". Each IR(VP) next installs all EID Prefixes (EPs) derived from its VPs into its FIB based on the mapping information received from each EUN that owns an EP. 4.2. IR(EP) Initialization Upon startup, each IR(EP) must register its EP-to-RLOC binding with the company that owns the corresponding VP, where the RLOC is an IPv4 or IPv6 address assigned to the IR(EP) by an ISP network. For example, if an IR(EP) owns the EP 192.2.1/24 (IPv4) and the RLOC assigned to the IR(EP) by the ISP is 2002:DB8::1 (IPv6), the IR(EP) informs the VP company that the route 192.2.1/24 -> 2002:DB8::1 must be added to the FIB in each of its IR(VPs) that aggregates the EP. The IR(EP) typically informs the VP company by using an authenticated short transaction protocol, e.g., http with username/password along with EP->RLOC mapping information. The exact specification for the short transaction is up to the VP company and need only be communicated to the IR(EP). The VP company then propagates this information to each of its IR(VPs) that aggregates the EP, e.g., via a routing protocol that all of the VP company's IR(VPs) engage in. After the IR(EP) informs the VP company of its EP->RLOC mapping, it resolves a FQDN for the VP company in order to discover the RLOC addresses and geographic locations of the IR(VPs) owned by the company. The IR(EP) then picks the closest subset of these RLOC addresses (typically 2-4 routers chosen, e.g., based on geographic distance), and adds them to a default router list of FIB entries that each points to a tunnel virtual interface with the RLOC as the next- hop address. The IR(EP) will then use these routes in the default router list as the means for forwarding encapsulated packets with EID source addresses toward the final destination via encapsulation. Templin Expires October 30, 2010 [Page 7] Internet-Draft IRON April 2010 5. IRON Operation Following IRON initialization, IRs engage in the steady-state process of receiving and forwarding packets. Except in instances when it forwards an unencapsulated packet to the public Internet, the IR encapsulates each forwarded packet using the mechanisms of VET [I-D.templin-intarea-vet] and SEAL [I-D.templin-intarea-seal]. IRs also use the SEAL Control Message Protocol (SCMP) to test liveness of other IRs and to receive redirects informing them of a better next hop. Each IR operates as specified in the following sections: 5.1. IR(EP) Operation After an IR(EP) is initialized, it sends periodic beacons to at least 2-4 of the IR(VPs) in its default router list. Each beacon is a SEAL Control Message Protocol (SCMP) Router Solicitation (RS) message, and will elicit an SCMP Router Advertisement (RA) message from the IR(VP). If the IR(EP) ceases to receive RA messages from a single IR(VP), it marks that IR(VP) as unreachable and selects a different IR(VP) as its primary default router. If the IR(EP) ceases to receive RA message from all IR(VPs), it marks the ISP connection as failed and uses a different ISP to re-register its EP-to-RLOC binding with its VP company using the RLOC assigned by the new ISP. When an end system in an EUN has a packet to send, the packet is forwarded through the EUN until it reaches the IR(EP). The IR(EP) then acts as an IR(S_EP) to forward a packet either to an IR(S_VP) or to an IR(D_EP). The IR(S_EP) first checks its FIB for the longest matching prefix. If the longest matching prefix is more-specific than "default", the IR(S_EP) forwards the packet to the next-hop the same as for ordinary IP forwarding, where the next hop will typically be an IR(D_EP). If the longest match is "default", however, the IR(S_EP) forwards the packet to one of its default routers. The IR(S_EP) uses VET and SEAL to encapsulate each forwarded packet in an outer IP header with the IP address of the next-hop IR as the destination address. The IR(S_EP) further uses SCMP to test liveness of and to receive SCMP redirect messages from the next-hop IR. When the IR(S_EP) receives an SCMP redirect, it checks the SEAL_ID field of the encapsulated message to verify that the redirect corresponds to a packet that it had previously sent to the neighbor and accepts the redirect if there is a match. Thereafter, subsequent packets forwarded by the IR(S_EP) will follow a route-optimized route. when an IR(EP) has a packet to forward from the EUN to a destination in a different network, it first checks its FIB for the longest matching prefix. If the longest matching prefix is more-specific than "default", the IR(EP) forwards the packet to the next hop IR Templin Expires October 30, 2010 [Page 8] Internet-Draft IRON April 2010 using VET/SEAL encapsulation. If the longest match is "default", however, the IR(EP) encapsulates the packet in an outer IP header with the IP address of an IR(VP) (discovered during initialization) as the destination address. The IR(EP) encapsulates the packet using the and 5.2. IR(VP) Operation After an IR(VP) is initialized, it responds to the periodic beacons sent by IR(EPs) as described in Section 5.1. When the IR(VP) receives an encapsulated packet, it first verifies that the inner and outer source addresses of the packet match an entry in its FIB, i.e., it performs an ingress filter check to confirm that the packet was sent by a legitimate IR(S_EP) or IR(S_VP). If there is a matching FIB entry, the IR(VP) accepts and decapsulates the packet; otherwise it discards the packet. The IR(VP) next examines the destination address of the decapsulated packet then acts as an IR(S_VP) to forward the packet as follows: o If the destination address matches an EP in its FIB, the IR(S_VP) re-encapsulates the packet using VET/SEAL, forwards it to the next-hop IR(D_EP) and sends an SCMP redirect message back to the previous hop IR. The previous hop IR will then install a route for the EP in its FIB and will send subsequent packets directly to the IR(D_EP). o If the destination address does not match an EP but matches a VP in its FIB, the IR(S_VP) re-encapsulates the packet using VET/ SEAL, forwards it to the next-hop IR(D_VP), but does not send an SCMP redirect message back to the previous hop IR. o if the destination address does not match an EP or a VP in the FIB, the IR(S_VP) forwards the unencapsulated packet to the public Internet via a default or more-specific route. When the IR(S_VP) forwards an encapsulated packet to an IR(D_VP) or an IR(D_EP), it may receive an SCMP redirect message informing it of a better next hop IR. The IR(S_VP) records the new route in its FIB and then relays a copy of the SCMP redirect message back to the IR from which it received the original encapsulated packet. Note that when an IR(S_VP) selects a next-hop IR(D_VP), it has no way of knowing whether the IR(D_VP) is reachable and able to process encapsulated packets. Therefore, the IR(S_VP) should select multiple IR(D_VPs) (e.g., 2-4), send the "live" packet to one of the IR(D_VPs) and send "blank" packets to the other IR(D_VPs). In turn, each IR(D_VP) accepts and forwards "live" packets, but drops "blank" packets after sending the redirect. In this way, even if the Templin Expires October 30, 2010 [Page 9] Internet-Draft IRON April 2010 original packet is lost due to short- or long-term outage, the IR(S_VP) should receive a redirect from at least one of the IR(D_VPs). 5.3. IR(GW) Operation Each VP company must establish one or more IR(GW) routers which advertise the full set of the company's VP's into the BGP. The VPs will be seen as ordinary routing information in the BGP, and any packets originating from the non-IRON Internet will be forwarded into the VP company's network by an IR(GW). When an IR(GW) receives a packet from the non-IRON Internet but destined to an EP destination, it consults its FIB to determine the best next-hop toward the final destination. The IR(GW) then encapsulates the packet using VET/SEAL then sends it to the next-hop IR the same as described for IR(VP) operation above. As for IR(VP) operation, when an IR(GW) forwards an encapsulated packet to an IR(D_VP), it may obtain more timely convergence by sending a "live" packet to one IR(D_VP) and "blanks" to others. 5.4. IRON Example Configuration and Scenario With respect to the previous sections, the following figure depicts a simple example IRON configuration and scenario: +------------+ +------------+ | | | | /======>+ IR(VP) A +======>+ IR(VP) B +======\ // | | | | \\ // +------------+ +------------+ \\ // V +----+-----+ +----+-----+ | IR(EP) A | ........................................> | IR(EP) B | +----+-----+ +----+-----+ | | ^^^^^+^^^^^^ ^^^^^+^^^^^^ ( EUN A ) ( EUN B ) -----+------ -----+------ | | +---+----+ +---+----+ | Host A | | Host B | +--------+ +--------+ Figure 1: Example IRON Configuration In this example, VP companies A and B have established IR(VP)s within the Internet that serve EP's to EUNs. EUN A has procured an EP from Templin Expires October 30, 2010 [Page 10] Internet-Draft IRON April 2010 VP company A, while EUN B has procured an EP from VP company B. The IR(EPs) and hosts in both EUNs have assigned addresses taken from their corresponding EPs on their EUN-interior interfaces, and the IR(EPs) have assigned provider-aggregated addresses taken from their ISPs on their WAN interfaces. When Host A in EUN A has a packet to send to Host B in EUN B, normal routing conveys the packet from Host A to IR(EP) A. Since IR(EP) A does not have a more-specific route, it encapsulates the packet and sends it via a tunnel to IR(VP) A (i.e., an IR(VP) owned by its VP company). IR(VP) A decapsulates the packet (since the packet source addresses match an EP route in its FIB) and checks its FIB for a route toward the packet's destination address. IR(VP) A does not have an EP route to B in its FIB, but it holds a full table of VP-to- RLOC mappings and discovers that the next-hop toward Host B is via IR(VP) B. IR(VP) A re-encapsulates the packet and sends it to IR(VP) B which has an EP route to B. IR(VP) B then re-encapsulates the packet and sends it to IR(EP) B, which decapsulates the packet and forwards it via EUN B to Host B. In this scenario, when IR(VP) B re-encapsulates the packet and forwards it to IR(EP) B, it also returns an SCMP redirect message to IR(VP) A. IR(VP) A then sets an EP route toward B in its FIB and relays the SCMP redirect message to IR(EP) A which also installs an EP route for B in its FIB. Subsequent packets from Host A to Host B then flow through a direct tunnel (shown as "...>") while bypassing the IR(VP) routers. Not discussed in this scenario are the operation of IR(GWs) (see Section 5.3) nor the mechanisms for IR(EP)s to switch between multiple ISPs. 6. Related Initiatives IRON builds upon the concepts RANGER architecture [I-D.templin-ranger], and therefore inherits the same set of related initiatives. Virtual Aggregation (VA) [I-D.ietf-grow-va] and Aggregation in Increasing Scopes (AIS) [I-D.zhang-evolution] provide the basis for the Virtual Prefix concepts. Internet vastly improved plumbing (Ivip) [I-D.whittle-ivip-arch] has contributed valuable insights, including the use of real-time mapping. Templin Expires October 30, 2010 [Page 11] Internet-Draft IRON April 2010 7. IANA Considerations The IANA is instructed to create a Master Virtual Prefix (MVP) registry for IRON. 8. Security Considerations Security considerations for RANGER apply also to IRON. 9. Acknowledgements This ideas behind this work have benefited greatly from discussions with colleagues; some of which appear on the RRG and other IRTF/IETF mailing lists. 10. References 10.1. Normative References [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, September 1981. [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", RFC 2460, December 1998. 10.2. Informative References [I-D.ietf-grow-va] Francis, P., Xu, X., Ballani, H., Jen, D., Raszuk, R., and L. Zhang, "FIB Suppression with Virtual Aggregation", draft-ietf-grow-va-02 (work in progress), March 2010. [I-D.russert-rangers] Russert, S., Fleischman, E., and F. Templin, "Operational Scenarios for IRON and RANGER", draft-russert-rangers-02 (work in progress), March 2010. [I-D.templin-intarea-seal] Templin, F., "The Subnetwork Encapsulation and Adaptation Layer (SEAL)", draft-templin-intarea-seal-13 (work in progress), March 2010. [I-D.templin-intarea-vet] Templin, F., "Virtual Enterprise Traversal (VET)", draft-templin-intarea-vet-10 (work in progress), Templin Expires October 30, 2010 [Page 12] Internet-Draft IRON April 2010 March 2010. [I-D.templin-ranger] Templin, F., "Routing and Addressing in Next-Generation EnteRprises (RANGER)", draft-templin-ranger-09 (work in progress), October 2009. [I-D.whittle-ivip-arch] Whittle, R., "Ivip (Internet Vastly Improved Plumbing) Architecture", draft-whittle-ivip-arch-04 (work in progress), March 2010. [I-D.zhang-evolution] Zhang, B. and L. Zhang, "Evolution Towards Global Routing Scalability", draft-zhang-evolution-02 (work in progress), October 2009. [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, January 2006. [RFC4548] Gray, E., Rutemiller, J., and G. Swallow, "Internet Code Point (ICP) Assignments for NSAP Addresses", RFC 4548, May 2006. Author's Address Fred L. Templin (editor) Boeing Research & Technology P.O. Box 3707 MC 7L-49 Seattle, WA 98124 USA Email: fltemplin@acm.org Templin Expires October 30, 2010 [Page 13]