FeedTreeSharing Web micronews with peertopeer event notification

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FeedTree--Sharing Web micronews with peer-to-peer
event notification

• Dan Sandler, Alan Mislove
• Rice University

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Brief View
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OUTLINE

• Terminology
• Pastry
• Scribe
• FeedTree
• Comments

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Terminology

• Micronews
• Event Notification
• Feed
• RSS

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RSS
WebServer
Client
user
Client
user
HTTP
HTTP
Client
user
HTTP
RSSresource
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Pastry
O
2128-1

• Rowstron-Druschel 2001
• DHT Functionality
• 128 bit circular id space
• nodeIds (uniform random)
• objIds (uniform random)
• Invariant node with numerically closest nodeId
  is objects root

objId
nodeIds
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PastryRouting
2128-1
O

• Msg with key X is routed to live node with nodeId
  closest to X
• Problem complete routing table not feasible

X
route(X,M)
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PastryRouting

• Properties
• log16 N steps
• O(log N) state
• Prefix matching algorithm

d471f1
d467c4
d462ba
d46a1c
d4213f
Route(d46a1c)
d13da3
65a1fc
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Description Pastry a peer-to-peer location
and routing substrate
0XXX
1XXX
2XXX
3XXX
1122
3321
START 1122 routes a message to 3000.
3032
First hop fixes first digit (3)
3001
Second hop fixes second digit (30)
END 3001 closest live node to 3000.

• Routes messages to the nodeId numerically closest
  to the destination in lt ?log2b (N)? steps
• Not only focuses on minimizing number of overlay
  hops but also the delay experienced
• Route chosen for a message is likely to be good
  with respect to the proximity metric

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ScribeCooperative group communication

• Scribe Tree-based group management
• Multicast, anycast, manycast primitives
• Scalable large numbers of groups, members, wide
  range of members/group

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Description Scribe is a Publish/Subscribe Event
Notification Application
Publisher
Publisher
Topic of interest
Subscriber
Subscriber

• Decentralized Peer-to-Peer Model
• A multicast tree is formed by joining the Pastry
  routes from each group member to a rendezvous
  point associated with a group.

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ScribeArchitecture
Scalable communication service
Subscription management Event notification
SCRIBE
P2P location and routing layer
PASTRY
DHT
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Tree-based protocols SCRIBE Tree Management

• Create route to groupId
• Join route to groupId
• Tree union of Pastry routes from members to the
  root.
• Multicast from the root down to the leaves
• Low link stress
• Low delay

Root
join( groupId)
groupId
Multicast (groupId)
join( groupId)
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Scribe Tree-based protocols SCRIBE Tree
Management
d467c4 root
26b20d
d471f1
d467c4 root
Proximity space
d13da3
65a1fc
65a1fc
Name space
d13da3
26b20d
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Design Joining a group (subscribing)and
multicasting a message (publishing)
Forwarder (may or may not be part of the group)
A1100
B1000
Event
C1011
1100
D1101
E1001
H1111
1101
1011
1001
F0100
G0111
0100
0111
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FeedTree --a Plan to Save RSS
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Design FeedTree sits on top of scribe/pastry
layer
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FeedTree Architecture

• A complete RSS document is created
• containing pieces of timely micronews
• Signed with the publishers private key
• Multicast in the overlay
• The user can be notified immediately

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Full FeedTree Support

• Web content management systems join the overlay
  by becoming long-lived FeedTree nodes
• It automatically creates a new FeedTree message
  and publishes it to multicast tree.

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Incremental FeedTree support

• Adapted to FeedTree with a republishing engine
• It sifting out new content and distributing it
  via FeedTree

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Development Status

• A software prototype
• Deployment internally at Rice
• Plan to expand to the PlanetLab

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Comments 1

• In this 6-page-long paper, only half page is
  actually about the FeedTree
• No experiments, no data, no evaluation!

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Lesson learned
A hot concept
A popular infrastructure
This paper


RSS Pastry Scribe Published!
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QA
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THANKS