One document matched: draft-petithuguenin-p2psip-proportional-quota-01.txt
Differences from draft-petithuguenin-p2psip-proportional-quota-00.txt
P2PSIP J. Rosenberg
Internet-Draft jdrosen.net
Intended status: Standards Track C. Jennings
Expires: January 5, 2012 Cisco
M. Petit-Huguenin
Stonyfish
July 4, 2011
Proportional Quota in REsource LOcation And Discovery (RELOAD)
draft-petithuguenin-p2psip-proportional-quota-01
Abstract
This document defines an extension to RELOAD [I-D.ietf-p2psip-base]
that limits the number of a specific kind element that can be stored
by one RELOAD peer.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. This document may not be modified,
and derivative works of it may not be created, except to format it
for publication as an RFC or to translate it into languages other
than English.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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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 January 5, 2012.
Copyright Notice
Copyright (c) 2011 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
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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. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Quota Algorithm . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Overlay Configuration Document Extension . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . . 5
8.2. Informative References . . . . . . . . . . . . . . . . . . 5
Appendix A. Release notes . . . . . . . . . . . . . . . . . . . . 5
A.1. Modifications between
draft-petithuguenin-p2psip-proportional-quota-01 and
draft-petithuguenin-p2psip-proportional-quota-00 . . . . . 5
A.2. Modifications between
draft-petithuguenin-p2psip-proportional-quota-00 and
draft-petithuguenin-vipr-reload-usage-00 . . . . . . . . . 6
A.3. Running Code Considerations . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
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1. Introduction
The base specification of RELOAD defines two variables to set the
storage quota. The first one is the maximum size of an element of a
specific kind, the second one is the maximum number of elements of a
specific kind that can be stored on a specific peer. The combination
of the two variables permits to limit the quantity of data that a
peer have to store.
For kinds that are used with an access control policy that does not
restrict the Resource-IDs, a different algorithm is needed to force
storing nodes to behave. This document describes a quota algorithm
that limits the number of elements of a specific kind that a node can
store in the overlay, independently of the Resource-ID used. Another
way to look at this quota algorithm is that an entity must provide a
number of peers that is proportional to the number of elements of a
specific kind that this entity wants to store.
It is important to understand that this quota works only for an
overlay comprising only peers, so with a configuration file
containing a <clients-permitted> element set to false.
2. Terminology
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 [RFC2119].
3. Quota Algorithm
A peer responsible for storing kinds using the quota algorithm
described in this document MUST maintain a count of the number of
unique entries being stored per signer for each kind. This operation
does not require to add a field containing the Node-ID as the Node-ID
of the signer is always available in the signature field of each
element stored.
For example if a peer is storing 5 Resource-IDs and at each of those
5 there are two keys whose first 16 bytes correspond to a particular
Node-ID, it means this node is currently storing 10 unique dictionary
entries for that Node-ID.
When performing the quota checks for an entry, the peer starts by
verifying that the size of the entry is consistent. It then takes
the <max-count> configuration parameter for this overlay, which
measures the amount of entries of a specific kind a particular node
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can store when a <max-count-per>SIGNER</max-count-per> configuration
parameter is also present. That value is multiplied by by the number
of replicas used by the topology plugin (i.e. 3 for Chord) and then
divided by the fraction of the overlay owned by this peer. If the
result is less than one, it is rounded up to two. This is the
maximum number of unique entries that can be stored for this signer.
If the peer is not yet storing this many entries for that Node-ID,
the store is allowed.
Note that when evaluating a Store Request containing multiple entries
per kind, the count of unique entries used for the evaluation is
incremented after each successful check, but the count will be reset
to its initial value if one of the check fails.
The algorithm takes in account only the duplications made by the
topology plugin. If another level of duplication is done at the
application level, the <max-count> value must be adjusted
accordingly.
Note that because of imperfect distribution of Resource-IDs across
the ring, new entries can be rejected even if the total count is
under the limit. It is the responsibility of the storing entity to
calculate the maximum acceptable probability of rejection and to
increase the number of peers accordingly.
4. Overlay Configuration Document Extension
This document extends the overlay configuration document by defining
a new element in the "urn:ietf:params:xml:ns:p2p:quota" namespace.
The <max-count-per> element changes the meaning of the <max-count>
variable. The value "PEER" forces the <max-count> to be interpreted
as been per storing peer, which is the default quota algorithm when
this extension is not used. The value "SIGNER" forces the <max-
count> to be interpreted as been per signer, which is the algorithm
defined by this document.
The Compact Relax NG Grammar for this element is:
namespace pqt = "urn:ietf:params:xml:ns:p2p:quota"
kind-parameter &= element pqt:max-count-per { max-count-per-type }
max-count-per-type |= "PEER"
max-count-per-type |= "SIGNER"
max-count-per-type |= xsd:string # extensions
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5. Security Considerations
TBD
6. IANA Considerations
This document adds the following URN to the "XML Namespaces" class of
the "IETF XML Registry":
urn:ietf:params:xml:ns:p2p:quota
7. Acknowledgements
This document was written with the xml2rfc tool described in
[RFC2629].
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[I-D.ietf-p2psip-base]
Jennings, C., Lowekamp, B., Rescorla, E., Baset, S., and
H. Schulzrinne, "REsource LOcation And Discovery (RELOAD)
Base Protocol", draft-ietf-p2psip-base-15 (work in
progress), May 2011.
8.2. Informative References
[RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
June 1999.
Appendix A. Release notes
This section must be removed before publication as an RFC.
A.1. Modifications between
draft-petithuguenin-p2psip-proportional-quota-01 and
draft-petithuguenin-p2psip-proportional-quota-00
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o Changed "storing peer" to "signer" as this works also for replica
peers.
o The default quota algorithm is per storing peer, not per
Resource-ID.
o Changed the constants in the XML extension accordingly.
o Added running code considerations for reference implementation.
A.2. Modifications between
draft-petithuguenin-p2psip-proportional-quota-00 and
draft-petithuguenin-vipr-reload-usage-00
o Instead of having a StorageQuota parameter that gives the maximum
number of entries, reused the max-count parameter (that is
mandatory anyway) and changes its meaning.
o Removed the 3x multiplier to account for the application layer
COPY, as it is application specific.
o Removed the additional 3x multiplier to compensate for imperfect
distribution, and moved the responsibility to the storing nodes.
A.3. Running Code Considerations
o Reference Implementation
(<http://debian.implementers.org/testing/source/reload.tar.gz>).
Marc Petit-Huguenin. Implements version -01.
Authors' Addresses
Jonathan Rosenberg
jdrosen.net
Monmouth, NJ
US
Email: jdrosen@jdrosen.net
URI: http://www.jdrosen.net
Cullen Jennings
Cisco
170 West Tasman Drive
San Jose, CA 95134
USA
Phone: +1 408 421-9990
Email: fluffy@cisco.com
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Marc Petit-Huguenin
Stonyfish
Email: marc@stonyfish.com
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