gossip peer sampling in real world · 2011-03-03 · 4/55 amir h. payberah – 22 june 2010 gossip...
TRANSCRIPT
![Page 1: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/1.jpg)
1/55Amir H. Payberah – 22 June 2010
Gossip Peer Sampling in Real World
Amir H. Payberah ([email protected])
![Page 2: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/2.jpg)
2/55Amir H. Payberah – 22 June 2010
Gossip Peer Sampling
![Page 3: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/3.jpg)
3/55Amir H. Payberah – 22 June 2010
Peer Sampling Service
• The peer sampling service provides each node with a list of nodes in the system.
•We would like that nodes are selected following a uniform random sample of all nodes in the system.
![Page 4: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/4.jpg)
4/55Amir H. Payberah – 22 June 2010
Gossip Peer Sampling Service
• One solution to achieve the uniform random selection is that every node knows all other nodes of the system. Not scalable
• Use a gossipbased dissemination of membership information to build an unstructured overlay. There are many variants of the basic gossipbased membership
dissemination idea, but it is not clear whether any of these variants actually lead to uniform sampling.
![Page 5: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/5.jpg)
5/55Amir H. Payberah – 22 June 2010
Generic Framework
• First, a node Q is selected to exchange membership information with by node P.
• Node P pushes its view to Q.
• If a reply is expected, the view is pulled from Q.
• They merge their current view and the received one, and select a new view.
![Page 6: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/6.jpg)
6/55Amir H. Payberah – 22 June 2010
Gossip Protocol (1/4)
![Page 7: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/7.jpg)
7/55Amir H. Payberah – 22 June 2010
Gossip Protocol (2/4)
gossip
![Page 8: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/8.jpg)
8/55Amir H. Payberah – 22 June 2010
Gossip Protocol (3/4)
reply
![Page 9: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/9.jpg)
9/55Amir H. Payberah – 22 June 2010
Gossip Protocol (4/4)
UpdateState
UpdateState
![Page 10: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/10.jpg)
10/55Amir H. Payberah – 22 June 2010
Design Space
•Peer Selection Rand Tail
•View Propagation Push PushPull
•View Selection Blind Healer Swapper
![Page 11: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/11.jpg)
11/55Amir H. Payberah – 22 June 2010
Impact of NAT on Gossip Peer Sampling Protocols
![Page 12: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/12.jpg)
12/55Amir H. Payberah – 22 June 2010
Natted Gossip Protocol (1/4)
gossip
![Page 13: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/13.jpg)
13/55Amir H. Payberah – 22 June 2010
Natted Gossip Protocol (2/4)
reply
![Page 14: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/14.jpg)
14/55Amir H. Payberah – 22 June 2010
Natted Gossip Protocol (3/4)
UpdateState
UpdateState
![Page 15: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/15.jpg)
15/55Amir H. Payberah – 22 June 2010
Natted Gossip Protocol (4/4)
gossip
![Page 16: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/16.jpg)
16/55Amir H. Payberah – 22 June 2010
Network Partition
View size: 15
View size: 27
![Page 17: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/17.jpg)
17/55Amir H. Payberah – 22 June 2010
Stale References
![Page 18: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/18.jpg)
18/55Amir H. Payberah – 22 June 2010
Randomness
![Page 19: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/19.jpg)
19/55Amir H. Payberah – 22 June 2010
Classic NAT Types
• Full Cone (FC): The most permissive type of NAT.
• Restricted Cone (RC): Imposes restrictions on the IP addresses of external peers that can send messages to natted peers.
• Port Restricted Cone (PRC): Imposes restrictions on the IP addresses and ports of external peers that can send messages to natted peers.
• Symmetric (SYM): The most restrictive type of NAT.
![Page 20: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/20.jpg)
20/55Amir H. Payberah – 22 June 2010
NAT Types
• NATs differ in: Way they assign public IP addresses (IP) Way assign ports (Port) Filtering rules (Filtering)
![Page 21: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/21.jpg)
21/55Amir H. Payberah – 22 June 2010
Classic NAT Types – FC
• IP: Same public IP to all sessions started from a given natted IP address and port.
• Port: Same port to all sessions started from a given natted IP address and port.
• Filtering: These sessions all share the same filtering rule, which states that the NAT must forward all incoming messages.
![Page 22: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/22.jpg)
22/55Amir H. Payberah – 22 June 2010
Classic NAT Types – RC
• IP: The same as FC.
• Port: The same as FC.
• Filtering: The sessions started from a given natted peer’s IP address and port towards a target IP address, share the same filtering rule: the NAT device only forwards messages coming from this IP address.
![Page 23: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/23.jpg)
23/55Amir H. Payberah – 22 June 2010
Classic NAT Types – PRC
• IP: The same as FC.
• Port: The same as FC.
• Filtering: The sessions started from a given natted peer’s IP address and port towards a target IP address and port, share the same filtering rule: the NAT device only forwards messages coming from this IP address and port.
![Page 24: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/24.jpg)
24/55Amir H. Payberah – 22 June 2010
Classic NAT Types – Symmetric
• IP: The same as FC.
• Port: Different port for each session started from a given natted IP address and port.
• Filtering: The same as PRC.
![Page 25: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/25.jpg)
25/55Amir H. Payberah – 22 June 2010
NATCracker Perspective
• Mapping policy: Decides when to bind a new port. Endpoint Independent (EI) Host Dependent (HD) Port Dependent (PD)
• Allocation policy: Decides which port should be bound. Port Preservation (PP) Port Contiguity (PC) Random (RD)
• Filtering policy: Decides whether a packet from the outside world to a public endpoint of a NAT gateway should be forwarded to the corresponding private endpoint. Endpoint Independent (EI) Host Dependent (HD) Port Dependent (PD)
![Page 26: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/26.jpg)
26/55Amir H. Payberah – 22 June 2010
NAT Traversal Techniques
• Hole punching (UDP)
• Relaying
When the destination node is behind a SYM NAT and the source node is either behind a PRC NAT or a SYM NAT.
When the destination node is behind a PRC NAT and the source node is behind a SYM NAT.
![Page 27: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/27.jpg)
27/55Amir H. Payberah – 22 June 2010
NAT Traversal Techniques – Hole Punching (UDP)
![Page 28: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/28.jpg)
28/55Amir H. Payberah – 22 June 2010
NAT Traversal Techniques – Relaying
![Page 29: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/29.jpg)
29/55Amir H. Payberah – 22 June 2010
Three Proposed Solutions
![Page 30: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/30.jpg)
30/55Amir H. Payberah – 22 June 2010
ARRG: RealWorld Gossiping
Niels Drost, Elth Ogston, Rob V. van Nieuwpoort and Henri E. BalVrije Universiteit Amsterdam
(HPDC'07)
![Page 31: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/31.jpg)
31/55Amir H. Payberah – 22 June 2010
Design Space
•Peer Selection Rand Blind
•View Propagation Push PushPull
•View Selection Blind Healer Swapper
![Page 32: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/32.jpg)
32/55Amir H. Payberah – 22 June 2010
The ARRG Protocol
• Actualized Robust Random Gossiping (ARRG).
• It uses Fallback Cache to solve the network connectivity problem.
• The Fallback Cache acts as a backup for the normal membership cache present in the gossiping algorithm.
• Each time a successful gossip exchange is done, the target of this gossip is added to the Fallback Cache.
•Whenever a gossip attempt fails, the Fallback Cache is used to select an entry to gossip with instead of the one selected by the original algorithm.
![Page 33: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/33.jpg)
33/55Amir H. Payberah – 22 June 2010
Example (1/4)
n1
n2
n3
n4
Fallback Cache
gossip
![Page 34: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/34.jpg)
34/55Amir H. Payberah – 22 June 2010
Example (2/4)
n1
n2
n3
n4
Fallback Cache
reply
n2
![Page 35: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/35.jpg)
35/55Amir H. Payberah – 22 June 2010
Example (3/4)
n1
n2
n3
n4
Fallback Cache
n2
gossip
![Page 36: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/36.jpg)
36/55Amir H. Payberah – 22 June 2010
Example (4/4)
n1
n2
n3
n4
Fallback Cache
n2
gossip
![Page 37: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/37.jpg)
37/55Amir H. Payberah – 22 June 2010
NATresilient Gossip Peer Sampling
AnneMarie Kermarrec, Alessio Pace, Vivien Quema, Valerio SchiavoniINRIA CNRS
(ICDCS'09)
![Page 38: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/38.jpg)
38/55Amir H. Payberah – 22 June 2010
Design Space
•Peer Selection Rand Blind
•View Propagation Push PushPull
•View Selection Blind Healer Swapper
![Page 39: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/39.jpg)
39/55Amir H. Payberah – 22 June 2010
The Nylon Protocol
• The main idea of Nylon is to implement reactive hole punching.
• A peer only performs hole punching towards peers it gossip with.
• Hole punching is implemented using a chain of RVPs that forward the OPEN HOLE message until it reaches the gossip target.
![Page 40: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/40.jpg)
40/55Amir H. Payberah – 22 June 2010
The Nylon Protocol
• Each node maintains a routing table that maintains the mapping between a natted node from its view and its associated RVP.
• For each node P in the routing table, the RVP is the node it shuffled with to obtain the reference to P.
• RVPs do not proactively refresh holes. Therefore, a time to live (TTL) is associated to each RVP entries in
routing tables.
![Page 41: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/41.jpg)
41/55Amir H. Payberah – 22 June 2010
Example (1/3)
n1 n2
rule TTL
n2: allow 120
Others: deny
dest RVP TTL
n2 120
rule TTL
n1: allow 120
Others: deny
dest RVP TTL
n1 120
Hole punching
n1 and n2 become RVP for each other.
Routing table
![Page 42: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/42.jpg)
42/55Amir H. Payberah – 22 June 2010
Example (2/3)
n1 n2
rule TTL
n2: allow 120
Others: deny
dest RVP TTL
n2 120
rule TTL
n2: allow 120
dest RVP TTL
n2 120
n2 and n3 become RVP for each other.
n3n2
rule TTL
n2: allow 120
Others: deny
dest RVP TTL
n2 120
n2
rule TTL
120
Others: deny
dest RVP TTL
n2 120
n2
rule TTL
n2: allow 120
Others: deny
dest RVP TTL
n2 120
n2
rule TTL
n1: allow 120
Others: deny
dest RVP TTL
n2 120
n2
rule TTL
n1: allow 120
n3: allow 140
Others: deny
dest RVP TTL
n1 120
n3 - 120
Hole punching
rule TTL
n2: allow 120
dest RVP TTL
n2 120
rule TTL
n2: allow 120
Others: deny
dest RVP TTL
n2 120
rule TTL
120
Others: deny
dest RVP TTL
n2 120
rule TTL
n2: allow 120
Others: deny
dest RVP TTL
n2 120
rule TTL
n1: allow 120
Others: deny
dest RVP TTL
n2 120
rule TTL
n1: allow 120
n3: allow 140
Others: deny
dest RVP TTL
n1 n2 120
n2 - 120
![Page 43: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/43.jpg)
43/55Amir H. Payberah – 22 June 2010
Example (3/3)
n1 n2
rule TTL
n2: allow 120
Others: deny
dest RVP TTL
n2 120
rule TTL
n2: allow 120
dest RVP TTL
n2 120
Through this chain n3 can shuffle with n1.n3 performs hole punching toward n1 by sending an OPEN_HOLE message to n2 that will forward it to n1.
n3n2
rule TTL
n2: allow 120
Others: deny
dest RVP TTL
n2 120
n2
rule TTL
120
Others: deny
dest RVP TTL
n2 120
n2
rule TTL
n2: allow 120
Others: deny
dest RVP TTL
n2 120
n2
rule TTL
n1: allow 120
Others: deny
dest RVP TTL
n2 120
n2
rule TTL
n1: allow 120
n3: allow 140
Others: deny
dest RVP TTL
n1 120
n3 - 120
OPEN_HOLE
rule TTL
n2: allow 120
dest RVP TTL
n2 120
rule TTL
n2: allow 120
Others: deny
dest RVP TTL
n2 120
rule TTL
120
Others: deny
dest RVP TTL
n2 120
rule TTL
n2: allow 120
Others: deny
dest RVP TTL
n2 120
rule TTL
n1: allow 120
Others: deny
dest RVP TTL
n2 120
rule TTL
n1: allow 120
n3: allow 140
Others: deny
dest RVP TTL
n1 n2 120
n2 - 120
OPEN_HOLE
![Page 44: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/44.jpg)
44/55Amir H. Payberah – 22 June 2010
Balancing Gossip Exchanges in Networks with Firewalls
Joao Leitao, Robbert van Renesse, Luıs RodriguesINESCID/IST Cornell University
(IPTPS'10)
![Page 45: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/45.jpg)
45/55Amir H. Payberah – 22 June 2010
Design Space
•Peer Selection Rand Blind
•View Propagation Push PushPull
•View Selection Blind Healer Swapper ?
![Page 46: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/46.jpg)
46/55Amir H. Payberah – 22 June 2010
The Protocol
• Each node maintains: A quota value (initially with a value of 1).
• Nodes increase their quota when they initiate a gossip exchange.
A singleentry cache for connections created by other nodes.• The connection cache keeps alive the last connection used by another peer to initiate a
gossip exchange.
•When a node receives a gossip request, engages in gossip exchange if: Has a quota value above zero. Has an empty connection cache. The gossip message has been already forwarded TTL times.
![Page 47: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/47.jpg)
47/55Amir H. Payberah – 22 June 2010
Example (1/8)
1 1 1
n1 n2 n3
![Page 48: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/48.jpg)
48/55Amir H. Payberah – 22 June 2010
Example (2/8)
2 1 1
n1 n2 n3gossip
![Page 49: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/49.jpg)
49/55Amir H. Payberah – 22 June 2010
Example (3/8)
2 0 1
n1 n2 n3reply
n1
![Page 50: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/50.jpg)
50/55Amir H. Payberah – 22 June 2010
Example (4/8)
2 0 2
n1 n2 n3
n1
gossip
![Page 51: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/51.jpg)
51/55Amir H. Payberah – 22 June 2010
Example (5/8)
2 0 2
n1 n2 n3
n1
gossipgossip
![Page 52: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/52.jpg)
52/55Amir H. Payberah – 22 June 2010
Example (6/8)
2 0 2
n1 n2 n3
n3
gossipgossip
![Page 53: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/53.jpg)
53/55Amir H. Payberah – 22 June 2010
Example (7/8)
1 0 2
n1 n2 n3
n3
reply
![Page 54: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/54.jpg)
54/55Amir H. Payberah – 22 June 2010
Example (8/8)
1 0 2
n1 n2 n3
n3
replyreply
![Page 55: Gossip Peer Sampling in Real World · 2011-03-03 · 4/55 Amir H. Payberah – 22 June 2010 Gossip Peer Sampling Service •One solution to achieve the uniform random selection is](https://reader034.vdocument.in/reader034/viewer/2022050511/5f9c403823d423656f0c0984/html5/thumbnails/55.jpg)
55/55Amir H. Payberah – 22 June 2010
Question?