Cachet Technologies 1998 Cachet Technologies Technology Overview February 1998.
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Transcript of Cachet Technologies 1998 Cachet Technologies Technology Overview February 1998.
Cachet Technologies 1998
Cachet TechnologiesCachet Technologies
Technology OverviewTechnology Overview
February 1998February 1998
Cachet Technologies 1998
OutlineOutline
Our Technology FocusOur Technology Focus First Application: Caching at the Edge of the First Application: Caching at the Edge of the
InternetInternet Comparison with Competing ProductsComparison with Competing Products Some Details of the TechnologySome Details of the Technology
– A new hashing protocolA new hashing protocol Other Potential ApplicationsOther Potential Applications Current PlansCurrent Plans
Cachet Technologies 1998
Technology FocusTechnology Focus
General:General:– Development of applications and infrastructure Development of applications and infrastructure
for distributed networks such as the Internet.for distributed networks such as the Internet. Current Emphasis:Current Emphasis:
– A solution to the A solution to the Resource Location ProblemResource Location Problem in in distributed networks.distributed networks.
Cachet Technologies 1998
Resource Location ProblemResource Location Problem
Where to put “it”Where to put “it” and and how to find “it”how to find “it” in a in a rapidly changing environment where there rapidly changing environment where there is no centralized control and information is is no centralized control and information is imperfect.imperfect.
Cachet Technologies 1998
First ApplicationFirst Application
Construction of large distributed caches at Construction of large distributed caches at the edges of the Internetthe edges of the Internet– Keeps commonly accessed items close to usersKeeps commonly accessed items close to users– Results in improved performance (e.g. latency) Results in improved performance (e.g. latency)
for users and decreased cost (e.g. bandwidth for users and decreased cost (e.g. bandwidth utilization) for service providersutilization) for service providers
– Can be sold to service providers and/or user Can be sold to service providers and/or user groups (e.g. companies) with 10-10M membersgroups (e.g. companies) with 10-10M members
Cachet Technologies 1998
ExampleExample
ISP
Internet
CNN
MIT
IBM
Users
Cachet Technologies 1998
ExampleExample
ISP
Internet
CNN
MIT
IBM
Cache
Users
Cachet Technologies 1998
Different ApproachesDifferent Approaches
Proxy Caches Proxy Caches (Microsoft, Cacheflow)(Microsoft, Cacheflow)
Monolithic Caches Monolithic Caches (Cisco, Inktomi)(Cisco, Inktomi)
– Large caches made up of clusters of machines Large caches made up of clusters of machines under under centralized controlcentralized control and placed at a and placed at a specific specific pointpoint in the network in the network
Distributed Caches Distributed Caches (NetCache)(NetCache)
– Large cache made up of Large cache made up of loosely coupledloosely coupled machines that are machines that are spread throughout the networkspread throughout the network
Cachet Technologies 1998
Monolithic vs. DistributedMonolithic vs. Distributed
Need faster response time for usersNeed faster response time for users– Caches should be close to the users at the edges Caches should be close to the users at the edges
of the network (Distributed)of the network (Distributed) Need reduced traffic out of networkNeed reduced traffic out of network
– Cache should have large capacity (Monolithic?)Cache should have large capacity (Monolithic?) Cachet’s Vision: Cachet’s Vision: DistributedDistributed caches that caches that
cooperatecooperate to form a cache with to form a cache with large large aggregate capacityaggregate capacity..
Cachet Technologies 1998
Necessary ComponentsNecessary Components
Resource LocationResource Location– Where do I put it and how do I find it?Where do I put it and how do I find it?
Resource DiscoveryResource Discovery– Who else is out there that will cooperate with Who else is out there that will cooperate with
me?me? Preventing Hot SpotsPreventing Hot Spots
– How do I cooperate without being overloaded How do I cooperate without being overloaded by requests?by requests?
Cachet Technologies 1998
Our Key TechnologiesOur Key Technologies
Invention of Invention of Consistent HashingConsistent Hashing to solve to solve resource location problemresource location problem
Discovery of protocols that enable caches to Discovery of protocols that enable caches to learn about the networklearn about the network
Development of a novel replication strategy Development of a novel replication strategy to prevent hot spotsto prevent hot spots– i.e. when to make more copies?i.e. when to make more copies?
Cachet Technologies 1998
Our AdvantagesOur Advantages
No special purpose hardwareNo special purpose hardware No centralized controlNo centralized control
– Very loosely coupled network of cachesVery loosely coupled network of caches Perfect information on status of caches is Perfect information on status of caches is
not needednot needed Fully scaleable and fault tolerantFully scaleable and fault tolerant Automatic load balancing Automatic load balancing Prevents swamping and hot spotsPrevents swamping and hot spots
Cachet Technologies 1998
Some of the DifficultiesSome of the Difficulties
Standard Way: Hashing h(x) = ax+b mod nStandard Way: Hashing h(x) = ax+b mod n
X
Where do I put file X?Where do I put file X? 1
2
3 4
5
Cachet Technologies 1998
Standard Hashing: The GoodStandard Hashing: The Good
Balanced loadBalanced load
Fast to compute Fast to compute
Local controlLocal control
Cachet Technologies 1998
Standard Hashing: The BadStandard Hashing: The Bad
Perfect information is neededPerfect information is needed
ax+b mod 4 = 2
Cachet Technologies 1998
Standard Hashing: The BadStandard Hashing: The Bad
Perfect information is neededPerfect information is needed
ax+b mod 4 = 2
Cachet Technologies 1998
Standard Hashing: The BadStandard Hashing: The Bad
Perfect information is neededPerfect information is needed
ax+b mod 4 = 2
Cachet Technologies 1998
Standard Hashing: The BadStandard Hashing: The Bad
Perfect information is neededPerfect information is needed
Cachet Technologies 1998
Standard Hashing: The UglyStandard Hashing: The Ugly
Small changes in the system cause drastic Small changes in the system cause drastic changes in the cachechanges in the cache
1 2 3 4 5 6 7 8 9 10 11
A
B
C
Caches
Pages
Cachet Technologies 1998
Standard Hashing: The UglyStandard Hashing: The Ugly
Small changes in the system cause drastic Small changes in the system cause drastic changes in the cachechanges in the cache
1 2 3 4 5 6 7 8 9 10 11
A
B
C
Caches
Pages
D
Cachet Technologies 1998
Standard Hashing: SummaryStandard Hashing: Summary
Useless for large and/or evolving distributed Useless for large and/or evolving distributed networksnetworks
Cachet Technologies 1998
Consistent HashingConsistent Hashing
Consistency under changing rangesConsistency under changing ranges
1 2 3 4 5 6 7 8 9 10 11
A
B
C
Caches
Pages
Cachet Technologies 1998
Consistent HashingConsistent Hashing
Consistency under changing rangesConsistency under changing ranges
1 2 3 4 5 6 7 8 9 10 11
A
B
C
Caches
Pages
D
Cachet Technologies 1998
Consistent Hashing: FeaturesConsistent Hashing: Features
Continuous balanced loadContinuous balanced load Fast to computeFast to compute Local controlLocal control Scales without any catastrophic updatingScales without any catastrophic updating Users need only partially correct view of the Users need only partially correct view of the
network. Enables network. Enables “lazy” resource discovery“lazy” resource discovery.. Enables resource location to take into account Enables resource location to take into account
load balancingload balancing and and geographic information.geographic information.
Cachet Technologies 1998
Related ApplicationsRelated Applications
Eliminating hot spots on the web (same Eliminating hot spots on the web (same technology on larger scale)technology on larger scale)
Distributed file serversDistributed file servers Swamping protection as a serviceSwamping protection as a service Distributed e-mail serversDistributed e-mail servers On-line moviesOn-line movies
Cachet Technologies 1998
Current PlansCurrent Plans
Implement Demo 1.0 at LCSImplement Demo 1.0 at LCS– Software package installed by user Software package installed by user – Program integrates automatically into loosly-coupled Program integrates automatically into loosly-coupled
distributed cachedistributed cache– Distributed cache performs as if a large virtual cache Distributed cache performs as if a large virtual cache
existed between LCS and the Internetexisted between LCS and the Internet
Development of market strategy and business Development of market strategy and business planplan
Secure VC funding and identify CEO for Secure VC funding and identify CEO for companycompany