draft-ietf-lisp-ms-07.txt   draft-ietf-lisp-ms-08.txt 
Network Working Group V. Fuller Network Working Group V. Fuller
Internet-Draft D. Farinacci Internet-Draft D. Farinacci
Intended status: Experimental cisco Systems Intended status: Experimental cisco Systems
Expires: September 11, 2011 March 10, 2011 Expires: October 29, 2011 April 27, 2011
LISP Map Server LISP Map Server
draft-ietf-lisp-ms-07.txt draft-ietf-lisp-ms-08.txt
Abstract Abstract
This draft describes the LISP Map-Server (LISP-MS), a computing This draft describes the LISP Map-Server (LISP-MS), a computing
system which provides a simplified LISP protocol interface as a system which provides a simplified LISP protocol interface as a
"front end" to the Endpoint-ID (EID) to Routing Locator (RLOC) "front end" to the Endpoint-ID (EID) to Routing Locator (RLOC)
mapping database and associated virtual network of LISP protocol mapping database and associated virtual network of LISP protocol
elements. elements.
The purpose of the Map-Server is to reduce implementation and The purpose of the Map-Server is to reduce implementation and
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 11, 2011. This Internet-Draft will expire on October 29, 2011.
Copyright Notice Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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appropriate ETR to answer those requests. On a LISP+ALT network, a appropriate ETR to answer those requests. On a LISP+ALT network, a
Map-Resolver acts as a "first-hop" ALT router. It has GRE tunnels Map-Resolver acts as a "first-hop" ALT router. It has GRE tunnels
configured to other ALT routers and uses BGP to learn paths to ETRs configured to other ALT routers and uses BGP to learn paths to ETRs
for different prefixes in the LISP+ALT database. The Map-Resolver for different prefixes in the LISP+ALT database. The Map-Resolver
uses this path information to forward Map-Requests over the ALT to uses this path information to forward Map-Requests over the ALT to
the correct ETRs. A Map-Resolver may operate in a non-caching mode, the correct ETRs. A Map-Resolver may operate in a non-caching mode,
where it simply de-capsulates and forwards the Encapsulated Map- where it simply de-capsulates and forwards the Encapsulated Map-
Requests that it receives from ITRs. Requests that it receives from ITRs.
Alternatively, a Map-Resolver may operate in a caching mode, where it Alternatively, a Map-Resolver may operate in a caching mode, where it
saves information about outsanding Map-Reqeusts, originates new Map- saves information about outstanding Map-Requests, originates new Map-
Requests to the correct ETR(s), accepts and caches the Map-Replies, Requests to the correct ETR(s), accepts and caches the Map-Replies,
and finally forwards the Map-Replies to the original ITRs. One and finally forwards the Map-Replies to the original ITRs. One
significant issue with use of caching in a Map-Resolver is that it significant issue with use of caching in a Map-Resolver is that it
hides the original ITR source of a Map-Request, which prevents an ETR hides the original ITR source of a Map-Request, which prevents an ETR
from tailoring its responses to that source; this reduces the inbound from tailoring its responses to that source; this reduces the inbound
traffic- engineering capability for the site owning the ETR. In traffic- engineering capability for the site owning the ETR. In
addition, caching in a Map-Resolver exacerbates problems associated addition, caching in a Map-Resolver exacerbates problems associated
with old mappings being cached; an outdated, cached mapping in an ITR with old mappings being cached; an outdated, cached mapping in an ITR
affects only that ITR and traffic originated by its site while an affects only that ITR and traffic originated by its site while an
outdate, cached mapping in a Map-Resolver could cause a problem with outdate, cached mapping in a Map-Resolver could cause a problem with
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non-existent EID (and rely on Negative Map-Replies) if it can consult non-existent EID (and rely on Negative Map-Replies) if it can consult
the ALT database to verify that an EID-prefix is present before the ALT database to verify that an EID-prefix is present before
sending that Map-Request. sending that Map-Request.
4.2. ETR/Map-Server EID Prefix Registration 4.2. ETR/Map-Server EID Prefix Registration
An ETR publishes its EID-prefixes on a Map-Server by sending LISP An ETR publishes its EID-prefixes on a Map-Server by sending LISP
Map-Register messages. A Map-Register message includes Map-Register messages. A Map-Register message includes
authentication data, so prior to sending a Map-Register message, the authentication data, so prior to sending a Map-Register message, the
ETR and Map-Server must be configured with a secret shared-key. A ETR and Map-Server must be configured with a secret shared-key. A
Map-Server's configuration should also include a list of the EID- Map-Server's configuration must also include a list of the EID-
prefixes for which each ETR is authoratative and should verify that a prefixes for which each ETR is authoritative. Upon receipt of a Map-
Map-Register received from an ETR only contain EID-prefixes that are Register from an ETR, a Map-Server accepts only EID-prefixes that are
associated with that ETR. While this check is not mandatory, it is configured for that ETR. Failure to implement such a check would
strongly encouraged as a failure to so leaves the mapping system leave the mapping system vulnerable to trivial EID-prefix hijacking
vulnerable to simple EID-prefix hijacking attacks. As developers and attacks. As developers and operators gain experience with the
users gain experience with the mapping system, additional, stronger mapping system, additional, stronger security measures may be added
security measures may be added to the registration process. to the registration process.
Map-Register messages are sent periodically from an ETR to a Map- Map-Register messages are sent periodically from an ETR to a Map-
Server with a suggested interval between messages of one minute. A Server with a suggested interval between messages of one minute. A
Map-Server should time-out and remove an ETR's registration if it has Map-Server should time-out and remove an ETR's registration if it has
not received a valid Map-Register message within the past three not received a valid Map-Register message within the past three
minutes. When first contacting a Map-Server after restart or changes minutes. When first contacting a Map-Server after restart or changes
to its EID-to-RLOC database mappings, an ETR may initially send Map- to its EID-to-RLOC database mappings, an ETR may initially send Map-
Register messages at an increased frequency, up to one every 20 Register messages at an increased frequency, up to one every 20
seconds. This "quick registration" period is limited to five minutes seconds. This "quick registration" period is limited to five minutes
in duration. in duration.
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quickly and how frequently a mapping database entry can be updated. quickly and how frequently a mapping database entry can be updated.
This may have implications for what sorts of mobility can supported This may have implications for what sorts of mobility can supported
directly by the mapping system. For a discussion on one way that directly by the mapping system. For a discussion on one way that
faster mobility may be implemented for individual devices, please see faster mobility may be implemented for individual devices, please see
[LISP-MN]. [LISP-MN].
An ETR may also request, by setting the "proxy-map-reply" flag An ETR may also request, by setting the "proxy-map-reply" flag
(P-bit) in the Map-Regsiter message, that a Map-Server answer Map- (P-bit) in the Map-Regsiter message, that a Map-Server answer Map-
Requests instead of forwarding them to the ETR. See [LISP] for Requests instead of forwarding them to the ETR. See [LISP] for
details on how the Map-Server sets certain flags (such as those details on how the Map-Server sets certain flags (such as those
indicating whether the message is authoratative and how returned indicating whether the message is authoritative and how returned
locators should be treated) when sending a Map-Reply on behalf of an locators should be treated) when sending a Map-Reply on behalf of an
ETR. ETR.
An ETR which uses a Map-Server to publish its EID-to-RLOC mappings An ETR which uses a Map-Server to publish its EID-to-RLOC mappings
does not need to participate further in the mapping database does not need to participate further in the mapping database
protocol(s). When using a LISP+ALT mapping database, for example, protocol(s). When using a LISP+ALT mapping database, for example,
this means that the ETR does not need to implement GRE or BGP, which this means that the ETR does not need to implement GRE or BGP, which
greatly simplifies its configuration and reduces its cost of greatly simplifies its configuration and reduces its cost of
operation. operation.
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7. Security Considerations 7. Security Considerations
The 2-way nonce exchange documented in [LISP] can be used to avoid The 2-way nonce exchange documented in [LISP] can be used to avoid
ITR spoofing attacks. ITR spoofing attacks.
To publish an authoritative EID-to-RLOC mapping with a Map-Server, an To publish an authoritative EID-to-RLOC mapping with a Map-Server, an
ETR includes authentication data that is a hash of the message using ETR includes authentication data that is a hash of the message using
pair-wise shared key. An implementation must support use of HMAC- pair-wise shared key. An implementation must support use of HMAC-
SHA-1-160 [RFC2104] and should support use of HMAC-SHA-256-128 SHA-1-160 [RFC2104] and should support use of HMAC-SHA-256-128
[RFC4634] (SHA-256 truncated to 128 bits). Key changes are initially [RFC4634] (SHA-256 truncated to 128 bits).
expected to be manual though a key-chaining scheme may be developed
as a future extension of this specification. During experimental and prototype deployment, authentication key
changes will be manual. Should LISP and its components be considered
for IETF standardization, further work will be required to follow the
BCP 107 [RFC4107] recommendations on automated key management.
As noted in Section 4.2, a Map-Server should verify that all EID- As noted in Section 4.2, a Map-Server should verify that all EID-
prefixes registered by an ETR match configuration stored on the Map- prefixes registered by an ETR match configuration stored on the Map-
Server. Server.
[LISP-SEC] defines a mechanism for providing origin authentication, [LISP-SEC] defines a mechanism for providing origin authentication,
integrity, anti-reply protection, and prevention of man-in-the-middle integrity, anti-reply protection, and prevention of man-in-the-middle
and "overclaiming" attacks on the Map-Request/Map-Reply exchange. and "overclaiming" attacks on the Map-Request/Map-Reply exchange.
While beyond the scope of securing an individual Map-Server or Map- While beyond the scope of securing an individual Map-Server or Map-
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8. References 8. References
8.1. Normative References 8.1. Normative References
[ALT] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "LISP [ALT] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "LISP
Alternative Topology (LISP-ALT)", Alternative Topology (LISP-ALT)",
draft-ietf-lisp-alt-06.txt (work in progress), March 2011. draft-ietf-lisp-alt-06.txt (work in progress), March 2011.
[LISP] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, [LISP] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis,
"Locator/ID Separation Protocol (LISP)", "Locator/ID Separation Protocol (LISP)",
draft-ietf-lisp-10.txt (work in progress), March 2011. draft-ietf-lisp-12.txt (work in progress), April 2011.
[RFC1035] Mockapetris, P., "Domain names - implementation and [RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987. specification", STD 13, RFC 1035, November 1987.
[RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed- [RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
Hashing for Message Authentication", RFC 2104, Hashing for Message Authentication", RFC 2104,
February 1997. February 1997.
[RFC4634] Eastlake, D. and T. Hansen, "US Secure Hash Algorithms [RFC4634] Eastlake, D. and T. Hansen, "US Secure Hash Algorithms
(SHA and HMAC-SHA)", RFC 4634, July 2006. (SHA and HMAC-SHA)", RFC 4634, July 2006.
skipping to change at page 16, line 5 skipping to change at page 15, line 9
[LISP-SEC] [LISP-SEC]
Maino, F., Ermagan, V., Cabellos, A., Sanchez, D., and O. Maino, F., Ermagan, V., Cabellos, A., Sanchez, D., and O.
Bonaventure, "LISP-Security", draft-maino-lisp-sec-00.txt Bonaventure, "LISP-Security", draft-maino-lisp-sec-00.txt
(work in progress), March 2011. (work in progress), March 2011.
[NERD] Lear, E., "NERD: A Not-so-novel EID to RLOC Database", [NERD] Lear, E., "NERD: A Not-so-novel EID to RLOC Database",
draft-lear-lisp-nerd-08.txt (work in progress), draft-lear-lisp-nerd-08.txt (work in progress),
March 2010. March 2010.
[RFC4107] Bellovin, S. and R. Housley, "Guidelines for Cryptographic
Key Management", BCP 107, RFC 4107, June 2005.
Appendix A. Acknowledgments Appendix A. Acknowledgments
The authors would like to thank Greg Schudel, Darrel Lewis, John The authors would like to thank Greg Schudel, Darrel Lewis, John
Zwiebel, Andrew Partan, Dave Meyer, Isidor Kouvelas, Jesper Skriver, Zwiebel, Andrew Partan, Dave Meyer, Isidor Kouvelas, Jesper Skriver,
Fabio Maino, and members of the lisp@ietf.org mailing list for their Fabio Maino, and members of the lisp@ietf.org mailing list for their
feedback and helpful suggestions. feedback and helpful suggestions.
Special thanks are due to Noel Chiappa for his extensive work on Special thanks are due to Noel Chiappa for his extensive work on
caching with LISP-CONS, some of which may be used by Map-Resolvers. caching with LISP-CONS, some of which may be used by Map-Resolvers.
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