Network Working Group D. Saucez Internet-Draft INRIA Sophia Antipolis Intended status: Informational October 21, 2011 Expires: April 23, 2012 CCN Router Interconnection with LISP draft-saucez-lisp-ccn-00 Abstract Content distribution prevails in today's Internet and Content-Centric Networking (CCN) proposes to access the data directly by their content instead of their location. In this memo we present a LISP based solution to interconnect CCN routers over the Internet. We first describe how content names can be encoded in LISP with LCAF. We then detail the operations of CCN routers to determine the CCN routers to which forward Interest and Data messages. 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. 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Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Data Name Encoding with LCAF . . . . . . . . . . . . . . . . . 3 3. Data Name to RLOC Mappings . . . . . . . . . . . . . . . . . . 4 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 5. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 5 6. Informative References . . . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 6 Saucez Expires April 23, 2012 [Page 2] Internet-Draft LISP for CCN October 2011 1. Introduction Content distribution prevails in today's Internet. This shift of paradigm implies the adoption of new techniques to distribute data based on the content instead of the location. To this aim, Content- Centric Networking (CCN) has been proposed [CCN]. In CCN content requester sends an Interest to its CCN router neighbors that propagate the Interest to the neighbors and so on until a router that owns or cache the Data of interest is reached. The corresponding Data is sent by this router and walk back to the requester. Intermediate CCN routers can cache the Data to speed-up the content retrieval in case of the same content is requested later. CCN is fundamentally different to what we are used today with location based retrieval (a DNS name is resolved into the address of a particular server where the content corresponding to the name is stored). Indeed, with CCN, the content can be anywhere (e.g., stored in a cache). CCN relies on hierarchical content naming to enable name aggregation. The aggregation follows the longest prefix matching lookup principle. Name are of the form "/User or App supplied name/Versioning/ Segmentation". For example, "/ietf.org/id/txt/draft-saucez-lisp-ccn/_00/_s1" could be used to represent the segment 1 of the version 00 of the I.D. "draft-saucez-lisp-ccn". In CCN this human readable Data name is encoded in binary as follow: 78ietf.org2id3txt21draft-saucez-lisp- ccn3FD000020001. LISP [I-D.ietf-lisp] could be used to allow CCN routers to be remotely interconnected over the Internet. LISP would be used to dynamically tunnel Interests and Data between CCN routers. If CCN routers run LISP, they can associate names to CCN routers with the mappings. For CCN, a LISP mapping associates Data names to RLOCs. Section 2 describes how to encode CCN Data names in LISP with LISP Canonical Addresses [I-D.farinacci-lisp-lcaf]. Section 3 shows how a LISP enabled CCN router can retrieve CCN Data name to RLOC mappings. We assume that the mapping system supports LCAF. 2. Data Name Encoding with LCAF Mappings in LISP associate an EID prefix to a list of RLOCs. In general, EIDs and RLOCs are IP. However, LISP is not limited to IP as it relies on AFIs. Moreover, the 16387 AFI is reserved for the LISP Canonical Address Format (LCAF) [I-D.farinacci-lisp-lcaf]. LCAF specifies a TLV based format to encode EIDs in a flexible way. Saucez Expires April 23, 2012 [Page 3] Internet-Draft LISP for CCN October 2011 Data names can be encoded with LCAF opaque keys. The Key Field Num field set to 0 and the Key Wildcard Fields field set to 0x0. The Key Field Num determines the number of equal-length fields the opaque key can be broken up into. The different parts of the Data address being of any arbitrary length, the Data address must be considered as a single field that cannot be decomposed. The Key Wildcard Fields determines the key parts that must not be considered for the lookup. As the whole key must be taken into account, all the bits in the field must be set to 0. 3. Data Name to RLOC Mappings In order to encapsulate the CCN messages and forward them to the appropriate CCN routers, the CCN router must know the CCN routers to which send the Interest and Data messages. To do so, Data names are associated to a list of RLOCS as if they were normal EID. If no entry exists in the CCN router FIB for the Data name in a received Interest. The CCN router triggers a miss and a Map-Request is sent on the CCN mapping system instance. The requested EID being the Data name in the Interest that triggered the miss. If a mapping exists for this Data name, the mapping will eventually be installed in the LISP enabled CCN router. Upon mapping reception, one virtual interface per RLOC is created and associated to the Interest. Priority and weight can be used to prefer some RLOC and Interests can be simultaneously sent to all the preferred RLOC. CCN focuses on content, not on location. A CCN router thus have no information about the CCN router that originated an Interest: the PIT only associates the Interest to the requesting faces and the Interest contains no information about the requester. If we call D the CCN router that received the Interest message and I the CCN router that sent the Interest message. D can use gleaning to back-walk the Data message to the appropriate CCN router (i.e., I). When D receives an Interest message, it gleans I's EID and I's RLOC. The RLOC is the IP address used for the LISP encapsulation. The EID must be a Data name. The CCN router then creates a virtual face to which it associates the gleaned mapping. When a Data message is sent on this face (i.e., when D receives a Data message for the Interest), the virtual face LISP encapsulates the Data message and fixes the destination EID to the gleaned EID associated to the face. The gleaned mapping is stored for a time equal to the timer associated to the Interest in the PIT. Only LISP encapsulated messages must trigger the gleaning and virtual face creation. When LISP encapsulated message is received, it must simply be decaspsulated and processed by the CCN instance. I and D EIDs must be Data names. To this aim, every LISP interface of a LISP enabled CCN router is Saucez Expires April 23, 2012 [Page 4] Internet-Draft LISP for CCN October 2011 assigned a unique name. This name has no other purpose than identifying the LISP interface for the Data message walk back. We propose to use the form /LISP/RLOC/IPv4/192.0.2.1 (resp. /LISP/RLOC/ IPv6/2001:DB8::1) where 192.0.2.1 (resp. 2001:DB8::1) is the RLOC used for the encapsulation. This way of naming the interface allows dynamic, and configurationless name generation. As explained above, CCN relies on hierarchical content naming to enable name aggregation. It thus mean that perfect matching for the Interest might not exist in the mapping system (e.g., a CCN node aggregates all the I.D. within the /ietf.org/id/txt prefix). However, LCAF implements an exact matching method. Thus, if the mapping system has /ietf.org/id/txt but not /ietf.org/id/txt/draft-saucez-lisp-ccn/_00/_s1, the mapping system returns no mapping for the request while /ietf.org/id/txt would had been returned. To overcome this limitation, the requester can send a Map-Request with several EIDs or several Map-Requests. In our example, the requester could send requests for /ietf.org/id/txt/draft-saucez-lisp-ccn/_00/_s1, /ietf.org/id/txt/draft-saucez-lisp-ccn/_00/ /ietf.org/id/txt/draft-saucez-lisp-ccn/ /ietf.org/id/txt/, /ietf.org/id and /ietf.org. The requester then encapuslates the Interest message to the mapping associated with the longest prefix it requested. 4. Security Considerations TO DO 5. Conclusion Content distribution prevails in today's Internet and Content-Centric Networking (CCN) proposes to access the data directly by their content instead of their location. In this memo we present a LISP based solution to interconnect CCN routers over the Internet. We first describe how content names can be encoded in LISP with LCAF. We then detail the operations of CCN routers to determine the CCN routers to which forward Interest and Data messages. 6. Informative References [CCN] Van Jacobson, Diana K. Smetters, James D. Thornton, Michael F. Plass, Nicholas H. Briggs, and Rebecca L. Braynard, "Networking Named Content", CoNEXT 2009, December 2009. Saucez Expires April 23, 2012 [Page 5] Internet-Draft LISP for CCN October 2011 [I-D.farinacci-lisp-lcaf] Farinacci, D., Meyer, D., and J. Snijders, "LISP Canonical Address Format (LCAF)", draft-farinacci-lisp-lcaf-05 (work in progress), April 2011. [I-D.ietf-lisp] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "Locator/ID Separation Protocol (LISP)", draft-ietf-lisp-15 (work in progress), July 2011. Author's Address Damien Saucez INRIA Sophia Antipolis 2004, Route des Lucioles BP 93 06902 Sophia Antipolis CEDEX, France Email: damien.saucez@inria.fr Saucez Expires April 23, 2012 [Page 6]