Internet DRAFT - draft-jiachen-icn-pubsub
draft-jiachen-icn-pubsub
ICNRG M. Arumaithurai
Internet-Draft J. Chen
Intended status: Informational X. Fu
Expires: September 6, 2015 University of Goettingen
K. Ramakrishnan
University of California, Riverside
J. Seedorf
NEC
March 5, 2015
Enabling Publish/Subscribe in ICN
draft-jiachen-icn-pubsub-01
Abstract
Information-Centric Networks (ICN) provide substantial flexibility
for users to obtain information without regard to the source of the
information or its current location. Publish/subscribe (pub/sub)
systems have gained popularity in society to provide the convenience
of removing the temporal dependency of the user having to indicate an
interest each time he or she wants to receive a particular piece of
related information. Such an "information-centric" communication
model should be supported in the new ICN network paradigm. This
document outlines some research directions for ICN with respect to
enhancing the inherently pull-based ICN approaches for achieving
efficient pub/sub capability.
Status of This Memo
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This Internet-Draft will expire on September 6, 2015.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Pub/Sub Communication . . . . . . . . . . . . . . . . . . . . 3
3. Scenarios of Pub/Sub Architecture . . . . . . . . . . . . . . 4
3.1. Online Social Networks and RSS Feeds . . . . . . . . . . 4
3.2. Online Gaming and Audio/Video Conferencing . . . . . . . 4
3.3. Notification Systems in Disaster . . . . . . . . . . . . 5
4. Requirements of an Efficient Pub/Sub Architecture . . . . . . 5
5. Related Work . . . . . . . . . . . . . . . . . . . . . . . . 7
5.1. IP/Overlay Multicast . . . . . . . . . . . . . . . . . . 7
5.2. Named-Data Networking (NDN) . . . . . . . . . . . . . . . 8
5.3. CCN . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.4. Content-Oriented Publish/Subscribe(COPSS) . . . . . . . . 9
5.5. PSIRP Project . . . . . . . . . . . . . . . . . . . . . . 9
5.6. NetInf Project (http://www.netinf.org) . . . . . . . . . 9
5.7. Pursuit Project (http://www.fp7-pursuit.eu/) . . . . . . 9
5.8. Other Related Works . . . . . . . . . . . . . . . . . . . 9
6. Standardisation Considerations . . . . . . . . . . . . . . . 10
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.1. Normative References . . . . . . . . . . . . . . . . . . 11
7.2. Informative References . . . . . . . . . . . . . . . . . 11
Appendix A. Acknowledgment . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction
This document points out the need to support publish/subscribe (pub/
sub) capabilities in ICN and the problems with the existing
solutions. Further, the document discusses potential directions for
enhancing Information Centric Networking (ICN) to achieve efficient
pub/sub.
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Section 2 describes the pub/sub systems and the challenges of such
systems to the current Internet. Section 3 demonstrates the use of
pub/sub systems in different scenarios. Section 4 outlines the
requirements of an efficient pub/sub architecture and Section 5
discusses the related works and some possible shortcomings. In
Section 6 we brief our standardisation considerations.
2. Pub/Sub Communication
Users increasingly desire access to information, ranging from news,
financial markets, healthcare, to disaster relief and beyond,
independent of who published it, where it is located, and often, when
it was published. Typical representation of these usages are
microblogs, RSS feed, social network, search engines, etc. A
consumer may not wish (or it may even be infeasible) to receive all
of the "channels" belonging to a myriad of information providers that
disseminate items of interest, either on demand (such as web,
twitter, blogs and social networks), or tune to a broadcast channel
(e.g., television, radio, newspaper). In these cases, the consumer
would rather prefer obtaining the data based on Content Descriptors
(CD) such as a keyword, a tag, or a property of the content
(publisher identity, published date etc.).
Publish/subscribe (pub/sub) systems are particularly suited for such
kind of large scale content-oriented information dissemination, and
provide the exibility for users to subscribe to information of
interest, without being intimately tied to when that information is
made available by publishers. With the use of an appropriate
interface, users can select and filter the information desired so
that they receive only what they are interested in, often
irrespective of the publisher.
Intelligent end-systems and information aggregators (e.g., Google
News and Yahoo! News, cable and satellite providers) have
increasingly adapted their interfaces to provide a content-oriented
pub/sub-based delivery method. However, these mechanisms are built
on top of a centralized server based framework and can also result in
a waste of network resources as shown in
[Ramasubramanian2006][Katsaros2011], since the Internet protocol
suite is focused on end-to-end delivery of data. Furthermore, issues
of "coverage" and "timeliness" still exist in such forms of
dissemination, where the aggregator may be selective in what
information is made available.
Information-Centric Networks (ICN) is a new network paradigm that
intendeds to achieve large scale data delivery with greater ease for
users, greater scalability in terms of the amount of information
disseminated as well as number of producers and consumers of
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information, and greater efficiency in terms of network and server
resource utilization.
It is also desirable for such a network to assist the pub/sub
communication model that delivers the information from any of the
producers to all subscribers. Moreover, it is desirable for the
network to assist in delivering fine-grained information to the
subscriber.
Recently, works such as
[Schmidt2012],[Carzaniga2011],[Chen2011],[Chen2012] have also
highlighted the need for ICN to support a pub/sub like communication
model.
3. Scenarios of Pub/Sub Architecture
In this section, we list several use cases of pub/sub architectures
in ICN. They help us to understand the requirements of an efficient
pub/sub architecture and why the existing solutions fall short.
3.1. Online Social Networks and RSS Feeds
Online social networks (e.g., Twitter, Facebook, etc.) and Rich Site
Summary (RSS) feeds are typical use cases for a content-centric pub/
sub system. In such systems, the receivers receive messages either
from friends, followees, or from some information aggregators. They
do not care which exact machine is sending the message (content-
centric), nor do they know when and what is the name of the next
message they are going to receive (temporal separation).
To prevent the receivers from polling all the possible providers,
existing systems use web servers as rendezvous points: the publishers
send new messages to the servers and the receivers/subscribers poll
the server periodically. This still causes great wastage for the
(HTTP) servers answering "304 - Not Modified" repeatedly since the
message update frequency is usually lower than the polling frequency.
3.2. Online Gaming and Audio/Video Conferencing
Massively multiplayer online role-playing games (MMORPGs, e.g.,
Counter-Strike, Quake, World of Warcraft, etc.) and audio/video
conferencing (e.g., Skype meeting, Web Whiteboard, Etherpad, etc.) is
another kind of content-centric pub/sub systems. Similar to the
social network scenario, users in such systems only care about the
content, either the area of interest (AoI) or the conference
partners, and they do not know when and from where the next message
will come. But different from the previous scenario, such systems
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require real-time update (message) delivery and these messages are
usually smaller in size compared to the online social networks.
Many of these systems choose to use HTTPS or direct TCP connection
between the server and the users to enable the capability of server
"pushing" the updates to the user. But maintaining such links are
costly. MMORPGs usually limit the number of players in a same game
which greatly reduces the interesting of these games.
3.3. Notification Systems in Disaster
Disasters have often disrupted communications because of damages to
critical infrastructure. For instance in the aftermath of the
Japanese Earthquake in 2011, approximately 1,200,000 fixed telephone
lines and 15,000 base-stations were not functioning. On average, 22%
(with peaks up to 65% in some areas) of the base-stations had to shut
down due to the lack of power or damages to the infrastructure.
Contradictory to the loss of available hardware capacity, during and
in the aftermath of a disaster, there is a substantial increase in
the amount of traffic generated because of the natural anxiety and
panic among people and the need to organize rescue and emergency
services. Many of these traffic are in the form of a pub/sub
communication model, e.g., the government needs to publish some
notifications (recovery status, new shelter locations, etc.), the
refugees need to notify their friends about their safety, or people
needs to ask for help from ambulances or fire brigade. In the
Japanese case, the congestion caused by such traffic resulted in
restrictions in voice traffic up to 95%, including emergency priority
calls.
4. Requirements of an Efficient Pub/Sub Architecture
Given a pub/sub communication model as described in Section 2, on a
high-level one can derive the following (incomplete) list of basic
requirements:
o Decouple publishers and subscribers: In an ideal pub/sub
environment, publishers only focus on their core task of
publishing while not having to maintain membership status, and
subscribers receive content from a multitude of sources without
having to worry about maintaining a list of publishers and
frequently polling them for the availability of fresh data.
Moreover, a consumer may not wish (and it may even be infeasible)
to subscribe to all of the channels belonging to a myriad of
information providers that disseminate items of interest, either
on demand (such as web, twitter, blogs and social networks), or
tune to a broadcast channel (e.g., television, radio, newspaper).
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In these cases, support should be provided to the consumer who
would prefer obtaining the data based on descriptors such as
keywords, tags, or other properties of the published data.
o Push enabled dissemination: The ability to exploit push-based
delivery is a key to achieving timeliness and to avoid wasting
server and network resources because of redundant polls.
Therefore, an efficient pub/sub architecture must provide the
capability for publishers to push information to online
subscribers interested in it. Such timely dissemination is
necessary in many scenarios such as disaster (e.g., Tsunami)
warnings, stock market information, news and gaming.
o Scalability: The target architecture should be able to accommodate
a large number of subscribers as well as publishers (often
subscribers are also publishers as user-generated content becomes
common). Therefore, it should minimize the amount of states
maintained in the network, ensure the load on the publisher grows
slowly (sublinearly) with the number of subscribers. The load on
the subscribers should also grow slowly with the number of
publishers (e.g., dealing with the burden of duplicate
elimination). Importantly, the load on the network should not
grow significantly with the growth in the number of publishers and
subscribers. There is also a need to accommodate a very large
range in the amount of information that may be disseminated, and
the need for all elements of the pub/sub framework in a content-
centric environment to scale in a manageable way.
o Efficiency: The architecture should enable a nearly unlimited
amount of information being generated by publishers, allow for
delivery of information related to subscriptions independent of
the frequency at which that information is generated by
publishers. The architecture must utilize network and server
resources efficiently. It is desirable that content is not
transmitted multiple times by a server or on a link. Furthermore,
the overhead on publisher and subscriber end-points to query
unnecessarily for information must be minimized.
o Dynamicity: The architecture should be able to deal with the
substantial churn in subscription state, allowing a large number
of users to join, leave and frequently change their subscriptions.
The topics of interest may change frequently as well (e.g., in a
Twitter-like publishing environment, where the popular topics
change frequently).
Additionally, to support a full-fledge pub-sub environment, it is
desirable that the target system support the following additional
features:
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o Support hierarchies and context in naming content: It is desirable
to be able to exploit both context and hierarchies in identifying
content. Hierarchical naming has been recognized by NDN as well.
Exploiting context enables a richer identification of content (in
both subscriptions and published information), as noted in the
database community.
o Support two-step dissemination for policy control and user
interest: There is a need for pub/sub environments to support a
two-step dissemination process both for reasons of policy and
access control at the publisher as well as managing delivery of
large volume content. In such a scenario, the pub/sub framework
would be designed to publish only a snippet of the data
(containing a description of the content and the method how to
obtain it) to subscribers. The subscribers then request for the
content based on their interest and allowance.
o Subscriber offline support: Another typical characteristic of pub-
sub environments is that subscribers could be offline at the time
the data is published. There is clearly a need for asynchronous
delivery of information in a pub/sub environment in an efficient,
seamless and scalable manner. The system needs to allow users who
were online to retrieve the data that they have missed. It should
also allow new subscribers to retrieve previously published
content that they are interested in. We envisage a server that
stores all the content published.
o Prevent Spam/DoS: Spam and DoS attacks are security issues that
concern push based pub/sub mechanisms. Efforts to mitigate this
at the network layer as well as at the application layer should be
considered.
Additionally, it will be desirable to have the following features to
support a (limited) pub-sub environment in a disaster affected
scneario:
o TBD
o TBD
5. Related Work
5.1. IP/Overlay Multicast
IP multicast [RFC1112] is a candidate solution for efficiently
delivering content to multiple receivers. A sender sends data to a
multicast group address that subscribers could join. Multicast
routing protocols such as PIM-SM [RFC4601] construct and maintain a
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tree from each sender to all receivers of a multicast group.
However, IP multicast isn't an efficient pub/sub delivery mechanism
for several reasons: 1) IP multicast is designed for delivery of
packets to connected end-points. Dealing with disconnected operation
(when subscribers are online) would have to be an application layer
issue. Overlay multicast solutions such as
[Jannotti2000][Chu2002][Banerjee2002] are agnostic of the underlying
network topology, usually relying on multiple unicasts in the
underlay path and are therefore also inefficient as a pub/sub
delivery mechanism. 2) The somewhat limited multicast group address
space makes it difficult to support a direct mapping of CDs to IP
multicast addresses. 3) Current IP multicast is not able to exploit
relationships between information elements, such as CDs. CDs may be
hierarchical or may have a contextual relationship, which enables
multiple CDs to be mapped to a group. For example, consider a
publisher that sends a message to all the subscribers interested in
football, and subscribers who are interested in receiving messages
about all sports. The message from the publisher will have to be
sent to two distinct IP multicast groups. If there happens to be a
subscriber of messages on sports and football, (s)he will receive the
same message twice and will have to perform redundancy elimination in
the application layer. The result is a waste in network traffic and
processing at both ends.
5.2. Named-Data Networking (NDN)
NDN has limited intrinsic support for pub/sub systems, a critical
need in a content centric environment. The aggregation of pending
Interests at routers achieves efficient dissemination of information
from NDN nodes. But this aggregation is similar to a cache hit in a
content distribution network (CDN) cache, which occurs only if
subscribers send their Interests with some temporal locality. Thus
it avoids multiple Interest queries having to be processed directly
by the content provider. Note however that this is still a pull-
based information delivery method and depends both on temporal
locality of interests and a large enough cache to achieve effective
caching in the (content centric) network. On the other hand, native
multicast support allows for a much more scalable push-based pub/sub
environment, since it is not sensitive to issues such as the cycling
of the cache when a large amount of information is disseminated.
TBD: Update it based on recent modifications by the NDN team
5.3. CCN
TBD: Update it based on recent modifications by the CCN team
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5.4. Content-Oriented Publish/Subscribe(COPSS)
COPSS enhances CCN/NDN with a push-based delivery mechanism using
multicast in a content-centric framework. It is designed to satisfy
the requirements mentioned above, especially to provide temporal
separation between subscription (or expression of Interest) and
publication. At the content-centric network layer, COPSS uses a
multiple-sender, multiple-receiver multicast capability, in much the
same manner as PIM-SM.
5.5. PSIRP Project
TBD
5.6. NetInf Project (http://www.netinf.org)
TBD
5.7. Pursuit Project (http://www.fp7-pursuit.eu/)
TBD
5.8. Other Related Works
Here we list the other related works we are considering. The list
might not be complete and we intend to add to it based on feedback
received in further revisions.
o A. Carzaniga, M. Rutherford, A. Wolf, A routing scheme for
content-based networking, in: INFOCOM, 2004.
o B. Segall, D. Arnold, J. Boot, M. Henderson, T. Phelps,
Content Based Routing with Elvin, in: AUUG2K, 2000.
o C. Esteve, F. Verdi, M. Magalhaes, Towards a new generation of
information-oriented Internetworking architectures, in: ReArch,
2008.
o G. Chockler, R. Melamed, Y. Tock, R. Vitenberg, SpiderCast: a
scalable interest-aware overlay for topic-based pub/sub
communication, in: DEBS, 2007.
o H. Eriksson, Mbone: the multicast backbone, Commun. ACM 37 (8)
(1994) 54-60.
o M. Ott, L. French, R. Mago, D. Makwana, Xml-based semantic
multicast routing: an overlay network architecture for future
information services, in: GLOBECOM, 2004.
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o P. T. Eugster, P. A. Felber, R. Guerraoui, A.-M. Kermarrec,
The many faces of publish/subscribe, ACM Comput. Surv. 35 (2)
(2003) 114-131.
o R. Baldoni, R. Beraldi, V. Quema, L. Querzoni, S. Tucci-
Piergiovanni, TERA: topic-based event routing for peer-to-peer
architectures, in: DEBS, 2007.
o R. V. Renesse, K. P. Birman, W. Vogels, Astrolabe: A Robust
and Scalable Technology for Distributed System Monitoring,
Management, and Data Mining, ACM TOCS 21 (2001) 66-85.
o S. Voulgaris, E. Riviere, A.-M. Kermarrec, M. Van Steen, Sub-
2-Sub: Self-Organizing Content-Based Publish and Subscribe for
Dynamic and Large Scale Collaborative Networks, Research report,
INRIA (December 2005).
o T. Koponen, M. Chawla, B.-G. Chun, A. Ermolinskiy, K. H.
Kim, S. Shenker, I. Stoica, A data-oriented (and beyond) network
architecture, in: SIGCOMM, 2007.
o V. Ramasubramanian, R. Peterson, E. G. Sirer, Corona: a high
performance publish-subscribe system for the world wide web, in:
NSDI, 2006.
o V. Jacobson, D. K. Smetters, J. D. Thornton, M. F. Plass,
N. H. Briggs, R. L. Braynard, Networking Named Content, in:
CoNEXT, 2009.
o Y. Cui, B. Li, K. Nahrstedt, ostream: asynchronous streaming
multicast in application-layer overlay networks, JSAC 22 (1)
(2004) 91-106.
o Y. Diao, S. Rizvi, M. J. Franklin, Towards an internet-scale
XML dissemination service, in: VLDB, 2004.
6. Standardisation Considerations
Future versions of this document will outline a concrete protocol
specification for pub/sub support for ICN. Below some initial
standardisation considerations are outlined.
An initial list of details that need to be specified is the
following:
o Pub/Sub related interfaces/APIs
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o Pub/Sub related data structure modification to existing ICN
proposals
We are also considering to write a survey paper that accumulates all
the Pub/sub related work.
7. References
7.1. Normative References
[RFC1112] Deering, S., "Host extensions for IP multicasting", STD 5,
RFC 1112, August 1989.
[RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
"Protocol Independent Multicast - Sparse Mode (PIM-SM):
Protocol Specification (Revised)", RFC 4601, August 2006.
7.2. Informative References
[Banerjee2002]
Banerjee, S., Bhattacharjee, B., and C. Kommareddy,
"Scalable application layer multicast", SIGCOMM, 2002, .
[Carzaniga2011]
Carzaniga, A., Papalini, M., and A. Wolf, "Content-based
Publish/Subscribe Networking and Information-centric
Networking", Proceedings of the ACM SIGCOMM workshop on
Information-centric networking, ACM, 2011, .
[Chen2011]
Chen, J., Arumaithurai, M., Fu, X., and K. Ramakrishnan,
"COPSS: An Efficient Content Oriented Publish/Subscribe
System", ACM/IEEE 7th Symposium on Architectures for
Networking and Communications Systems (ANCS), 2011, .
[Chen2012]
Chen, J., Arumaithurai, M., Fu, X., and K. Ramakrishnan,
"G-COPSS: A Content Centric Communication Infrastructure
for Gaming Applications", IEEE 32nd International
Conference on Distributed Computing Systems (ICDCS), 2012,
.
[Chu2002] Chu, Y., Rao, S., Seshan, S., and H. Zhang, "A case for
end system multicast", IEEE Journal on Selected Areas in
Communications 20, no. 8 (2002): 1456-1471, .
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[Fenner2005]
Fenner, W., Rabinovich, M., Ramakrishnan, K., Srivastava,
D., and Y. Zhang, "XTreeNet: Scalable overlay networks for
XML content dissemination and querying (synopsis)", 10th
International Workshop on Web Content Caching and
Distribution (WCW), 2005, .
[Jannotti2000]
Jannotti, J., Gifford, D., Johnson, K., and M. Kaashoek,
"Overcast: reliable multicasting with on overlay network",
Proceedings of the 4th conference on Symposium on
Operating System Design & Implementation-Volume 4, pp.
14-14. USENIX Association, 2000, .
[Katsaros2011]
Katsaros, K., Xylomenos, G., and G. Polyzos, "MultiCache:
An overlay architecture for information-centric
networking", Computer Networks 55.4 (2011): 936-947, .
[Ramasubramanian2006]
Ramasubramanian, V., Peterson, R., and E. Sirer, "Corona:
A High Performance Publish-Subscribe System for the World
Wide Web", NSDI. Vol. 6. 2006, .
[Schmidt2012]
Schmidt, T. and M. Waehlisch, "Why We Shouldn t Forget
Multicast in Name-oriented Publish/Subscribe", arXiv
preprint arXiv:1201.0349 (2012), .
Appendix A. Acknowledgment
This document has been supported by the GreenICN project (GreenICN:
Architecture and Applications of Green Information Centric Networking
), a research project supported jointly by the European Commission
under its 7th Framework Program (contract no. 608518) and the
National Institute of Information and Communications Technology
(NICT) in Japan (contract no. 167). The views and conclusions
contained herein are those of the authors and should not be
interpreted as necessarily representing the official policies or
endorsements, either expressed or implied, of the GreenICN project,
the European Commission, or NICT.
Authors' Addresses
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Mayutan Arumaithurai
University of Goettingen
Goldschmidt Str. 7
Goettingen 37077
Germany
Phone: +49 551 39 172046
Fax: +49 551 39 14416
Email: arumaithurai@informatik.uni-goettingen.de
Jiachen Chen
University of Goettingen
Goldschmidt Str. 7
Goettingen 37077
Germany
Phone: +49 551 39 172051
Fax: +49 551 39 14416
Email: jiachen@informatik.uni-goettingen.de
Xiaoming Fu
University of Goettingen
Goldschmidt Str. 7
Goettingen 37077
Germany
Phone: +49 551 39 172023
Fax: +49 551 39 14416
Email: fu@informatik.uni-goettingen.de
K. K. Ramakrishnan
University of California, Riverside
900 University Ave
Riverside CA 92521
USA
Email: kkramakrishnan@yahoo.com
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Jan Seedorf
NEC
Kurfuerstenanlage 36
Heidelberg 69115
Germany
Phone: +49 6221 4342 221
Fax: +49 6221 4342 155
Email: seedorf@neclab.eu
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