--- 1/draft-ietf-opsawg-lsn-deployment-05.txt 2014-04-12 19:14:33.865845787 -0700 +++ 2/draft-ietf-opsawg-lsn-deployment-06.txt 2014-04-12 19:14:33.909846874 -0700 @@ -1,18 +1,18 @@ OPSAWG V. Kuarsingh, Ed. Internet-Draft J. Cianfarani Intended status: Informational Rogers Communications -Expires: July 27, 2014 January 23, 2014 +Expires: October 15, 2014 April 13, 2014 CGN Deployment with BGP/MPLS IP VPNs - draft-ietf-opsawg-lsn-deployment-05 + draft-ietf-opsawg-lsn-deployment-06 Abstract This document specifies a framework to integrate a Network Address Translation layer into an operator's network to function as a Carrier Grade NAT (also known as CGN or Large Scale NAT). The CGN infrastructure will often form a NAT444 environment as the subscriber home network will likely also maintain a subscriber side NAT function. Exhaustion of the IPv4 address pool is a major driver compelling some operators to implement CGN. Although operators may @@ -20,38 +20,39 @@ term needs may not be satisfied with an IPv6 deployment alone. This document provides a practical integration model which allows the CGN platform to be integrated into the network, meeting the connectivity needs of the subscriber while being mindful of not disrupting existing services and meeting the technical challenges that CGN brings. The model included in this document utilizes BGP/MPLS IP VPNs which allow for virtual routing separation helping ease the CGNs impact on the network. This document does not intend to defend the merits of CGN. -Status of this Memo +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 July 27, 2014. + This Internet-Draft will expire on October 15, 2014. Copyright Notice + Copyright (c) 2014 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 @@ -53,54 +54,54 @@ (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 . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 1.1. Terms . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 2. Existing Network Considerations . . . . . . . . . . . . . . . 5 - 3. CGN Network Deployment Requirements . . . . . . . . . . . . . 5 - 3.1. Centralized versus Distributed Deployment . . . . . . . . 6 - 3.2. CGN and Traditional IPv4 Service Co-existence . . . . . . 7 - 3.3. CGN By-Pass . . . . . . . . . . . . . . . . . . . . . . . 7 - 3.4. Routing Plane Separation . . . . . . . . . . . . . . . . . 8 - 3.5. Flexible Deployment Options . . . . . . . . . . . . . . . 8 - 3.6. IPv4 Overlap Space . . . . . . . . . . . . . . . . . . . . 8 - 3.7. Transactional Logging for CGN Systems . . . . . . . . . . 9 - 3.8. Base CGN Requirements . . . . . . . . . . . . . . . . . . 9 - 4. BGP/MPLS IP VPN based CGN Framework . . . . . . . . . . . . . 9 - 4.1. Service Separation . . . . . . . . . . . . . . . . . . . . 11 - 4.2. Internal Service Delivery . . . . . . . . . . . . . . . . 12 - 4.2.1. Dual Stack Operation . . . . . . . . . . . . . . . . . 14 - 4.3. Deployment Flexibility . . . . . . . . . . . . . . . . . . 16 + 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 + 1.1. Terms . . . . . . . . . . . . . . . . . . . . . . . . . . 3 + 2. Existing Network Considerations . . . . . . . . . . . . . . . 4 + 3. CGN Network Deployment Requirements . . . . . . . . . . . . . 4 + 3.1. Centralized versus Distributed Deployment . . . . . . . . 5 + 3.2. CGN and Traditional IPv4 Service Co-existence . . . . . . 6 + 3.3. CGN By-Pass . . . . . . . . . . . . . . . . . . . . . . . 6 + 3.4. Routing Plane Separation . . . . . . . . . . . . . . . . 7 + 3.5. Flexible Deployment Options . . . . . . . . . . . . . . . 7 + 3.6. IPv4 Overlap Space . . . . . . . . . . . . . . . . . . . 7 + 3.7. Transactional Logging for CGN Systems . . . . . . . . . . 8 + 3.8. Base CGN Requirements . . . . . . . . . . . . . . . . . . 8 + 4. BGP/MPLS IP VPN based CGN Framework . . . . . . . . . . . . . 8 + 4.1. Service Separation . . . . . . . . . . . . . . . . . . . 10 + 4.2. Internal Service Delivery . . . . . . . . . . . . . . . . 11 + 4.2.1. Dual Stack Operation . . . . . . . . . . . . . . . . 13 + 4.3. Deployment Flexibility . . . . . . . . . . . . . . . . . 15 4.4. Comparison of BGP/MPLS IP VPN Option versus other CGN - Attachment Options . . . . . . . . . . . . . . . . . . . . 16 - 4.4.1. Policy Based Routing . . . . . . . . . . . . . . . . . 16 - 4.4.2. Traffic Engineering . . . . . . . . . . . . . . . . . 17 - 4.4.3. Multiple Routing Topologies . . . . . . . . . . . . . 17 - 4.5. Multicast Considerations . . . . . . . . . . . . . . . . . 17 - 5. Experiences . . . . . . . . . . . . . . . . . . . . . . . . . 17 - 5.1. Basic Integration and Requirements Support . . . . . . . . 17 - 5.2. Performance . . . . . . . . . . . . . . . . . . . . . . . 18 - 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 - 7. Security Considerations . . . . . . . . . . . . . . . . . . . 18 - 8. BGP/MPLS IP VPN CGN Framework Discussion . . . . . . . . . . . 18 - 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 19 - 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 19 - 10.1. Normative References . . . . . . . . . . . . . . . . . . . 19 - 10.2. Informative References . . . . . . . . . . . . . . . . . . 19 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20 + Attachment Options . . . . . . . . . . . . . . . . . . . 15 + 4.4.1. Policy Based Routing . . . . . . . . . . . . . . . . 15 + 4.4.2. Traffic Engineering . . . . . . . . . . . . . . . . . 16 + 4.4.3. Multiple Routing Topologies . . . . . . . . . . . . . 16 + 4.5. Multicast Considerations . . . . . . . . . . . . . . . . 16 + 5. Experiences . . . . . . . . . . . . . . . . . . . . . . . . . 16 + 5.1. Basic Integration and Requirements Support . . . . . . . 16 + 5.2. Performance . . . . . . . . . . . . . . . . . . . . . . . 17 + 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 + 7. Security Considerations . . . . . . . . . . . . . . . . . . . 17 + 8. BGP/MPLS IP VPN CGN Framework Discussion . . . . . . . . . . 17 + 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 18 + 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 + 10.1. Normative References . . . . . . . . . . . . . . . . . . 18 + 10.2. Informative References . . . . . . . . . . . . . . . . . 18 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19 1. Introduction Operators are faced with near term IPv4 address exhaustion challenges. Many operators may not have a sufficient amount of IPv4 addresses in the future to satisfy the needs of their growing subscriber base. This challenge may also be present before or during an active transition to IPv6 somewhat complicating the overall problem space. @@ -220,22 +221,22 @@ extend possible; Other requirements may be assessed on a operator-by-operator basis, but those listed above may be considered for any given deployment architecture. 3.1. Centralized versus Distributed Deployment Centralized deployments of CGN (longer proximity to end user and/or higher densities of subscribers/connections to CGN instances) differ - from distributed deployments of CGN (closer proximity to end user - and/or lower densities of subscribers/connections to CGN instances). + from distributed deployments of CGN (closer proximity to end user and + /or lower densities of subscribers/connections to CGN instances). Service providers may likely deploy CGN translation points more centrally during initial phases if the early system demand is low. Early deployments may see light loading on these new systems since legacy IPv4 services will continue to operate with most endpoints using globally unique IPv4 addresses. Exceptional cases which may drive heavy usage in initial stages may include operators who already translate a significant portion of their IPv4 traffic; may transition to a CGN implementation from legacy translation mechanisms (i.e. traditional firewalls); or build a green field deployment which may see quick growth in the number of new IPv4 endpoints which require @@ -331,32 +332,33 @@ subscriber base . The CGN deployment should provide mechanisms to manage IPv4 overlap if required. 3.7. Transactional Logging for CGN Systems CGNs may require transactional logging since the source IP and related transport protocol information is not easily visible to external hosts and system. If needed, the CGN systems should be able to generate logs which - identify internal realm host parameters (i.e. IP/Port) and - associated them to external realm parameters imposed by the - translator. The logged information should be stored on the CGN - hardware and/or exported to another system for processing. The - operator may choose to also enable mechanisms to help reduce logging - such as block allocation of UDP and TCP ports or deterministic - translation options such as [I-D.donley-behave-deterministic-cgn]. + identify internal realm host parameters (i.e. IP/Port) and associated + them to external realm parameters imposed by the translator. The + logged information should be stored on the CGN hardware and/or + exported to another system for processing. The operator may choose + to also enable mechanisms to help reduce logging such as block + allocation of UDP and TCP ports or deterministic translation options + such as [I-D.donley-behave-deterministic-cgn]. - Operators may need to keep track of this information (securely) to - meet regulatory and/or legal obligations. Further information can be - found in [RFC6888] with respect to CGN logging requirements (Logging - Section). + Operators may be legally obligated to keep track of translation + information. The operator may need to utilize their standard + practices in handling sensitive customer data when storing and/or + transporting such data. Further information can be found in + [RFC6888] with respect to CGN logging requirements (Logging section). 3.8. Base CGN Requirements Whereas the requirements above represent assessed architectural requirements, the CGN platform will also need to meet the need to meet the base CGN requirements of a CGN function. Base requirements include such functions as Bulk Port Allocation and other CGN device specific functions. These base CGN platform requirements are captured within [RFC6888]. @@ -523,23 +525,23 @@ | Local | | Content | +-----------+ Figure 2: Internal Services and CGN By-Pass An extension to the services delivery LSP is the ability to also provide direct subscriber to subscriber traffic flows between CGN zones. Each zone or realm may be fitted with separate CGN resources, but the subtending subscribers don't necessarily need to be mediated - (translated) by the CGN translators. This option, as shown in Figure - 3 below, is easy to implement and can only be enabled if no IPv4 - address overlap is used between communicating CGN zones. + (translated) by the CGN translators. This option, as shown in + Figure 3 below, is easy to implement and can only be enabled if no + IPv4 address overlap is used between communicating CGN zones. Access Node-1 VRF Termination CGN-1 +-------------+ +-----------+ +----------+ | | | | | | CPE-1 | +---------+ | | +-------+ | | +------+ | +-----+ | | | | | | | | | | | | | --+--+-+- VRF --+-+-+ | | VRF | | | | | | +-----+ | | | | | | | | | | | | | | +---------+ | | | +-------+ | | | | | | | | | | | |XLATE | | @@ -751,22 +753,26 @@ are typically used by subscribes within an operator environment. A full review of the observed impacts related to CGN (NAT444) are covered in [RFC7021]. 6. IANA Considerations This document has no IANA actions. 7. Security Considerations - The same security considerations would typically exist for CGN - deployments when compared with traditional IPv4 based services. + An operator implementing CGN using BGP/MPLS IP VPNs should refer to + [RFC6888] section 7 for security considerations related to CGN + deployments. The operator should continue to employ standard + security methods in place for their standard MPLS deployment and can + also refer to the security considerations section in [RFC4364] which + discusses both control plane and data plane security. 8. BGP/MPLS IP VPN CGN Framework Discussion The MPLS/VPN delivery method for a CGN deployment is an effective and scalable way to deliver mass translation services. The architecture avoids the complex requirements of traffic engineering and policy based routing when combining these new service flows to existing IPv4 operation. This is advantageous since the NAT44/CGN environments should be introduced with as little impact as possible and these environments are expected to change over time. @@ -791,37 +797,37 @@ 10.1. Normative References [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private Networks (VPNs)", RFC 4364, February 2006. 10.2. Informative References [I-D.donley-behave-deterministic-cgn] Donley, C., Grundemann, C., Sarawat, V., Sundaresan, K., and O. Vautrin, "Deterministic Address Mapping to Reduce - Logging in Carrier Grade NAT Deployments", - draft-donley-behave-deterministic-cgn-06 (work in - progress), July 2013. + Logging in Carrier Grade NAT Deployments", draft-donley- + behave-deterministic-cgn-07 (work in progress), January + 2014. [RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and - E. Lear, "Address Allocation for Private Internets", - BCP 5, RFC 1918, February 1996. + E. Lear, "Address Allocation for Private Internets", BCP + 5, RFC 1918, February 1996. [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol Label Switching Architecture", RFC 3031, January 2001. [RFC5332] Eckert, T., Rosen, E., Aggarwal, R., and Y. Rekhter, "MPLS Multicast Encapsulations", RFC 5332, August 2008. [RFC5969] Townsley, W. and O. Troan, "IPv6 Rapid Deployment on IPv4 - Infrastructures (6rd) -- Protocol Specification", - RFC 5969, August 2010. + Infrastructures (6rd) -- Protocol Specification", RFC + 5969, August 2010. [RFC6037] Rosen, E., Cai, Y., and IJ. Wijnands, "Cisco Systems' Solution for Multicast in BGP/MPLS IP VPNs", RFC 6037, October 2010. [RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful NAT64: Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers", RFC 6146, April 2011. [RFC6264] Jiang, S., Guo, D., and B. Carpenter, "An Incremental