Service Composition: Breakout Session Summary

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4 Δεκ 2013 (πριν από 4 χρόνια και 6 μήνες)

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Service Composition: Breakout
Session Summary

Randy Katz

David Culler

Summary: Bhaskaran Raman

Discussion topics


Emerging Internet service model

Confederated vs. Overlay model


Granularity of composition

Growth trends: copious bandwidth

Service economics


Emerging Internet service model

less cloud

Structured, with Internet data

Portal service built out of pieces


Appln infra service

Appln specific servers

Overlay networks

Physical topology

Confederated vs. Overlay model

At the network layer

At the service layer

Granularity of services

weight pieces

E.g., search engines

weight pieces

E.g., transformation agents

Yahoo portal is an example of heavy

Ninja paths: light
weight composition

Composition: beyond functionality

Service composition: flexibile

Can a composed service be robust?

Can we build in a negative feedback loop into the system?

With an event queue based approach to composition?

Can such a mechanism work across machines, across the

How to compute reliability of a composed service?

Who to blame when something breaks?

SLAs for services: complex

Yahoo/Google have legal SLA document

Design for decomposition

Design for decomposition: how to design a service
so that it can be built from pieces meaningfully

End argument in service composition:

If we want to have admission control at the end, how to
effect this when the bottleneck is in the middle?

How to design protocols to allow for composition?

Expose more information

E.g., HTTP/1.0 has little support for caches, HTTP/1.1
has a lot of support

Internet Growth Trends

Optical technology being deployed in a big way

1.6 Tb/s

24 Tb/s in the backbone

Where to place services, and how many service

Does it matter, if backbone bandwidth is free and

What about the people cost of managing distributed

In storage management, people cost is 3
4 times more than
system cost

Network access cost dropping: can buy optical link for $2K
a month

Service distribution vs. Centralization

Might depend on granularity

Hard to distribute search engine

Easier to distribute Akamai servers: soft

People cost:

HP: 50,000 node computer network

$10K per server

One person can manage 10 servers

Service in the telephone network are distributed

Might be related to the way the telephone network
evolved, and its architecture

Service distribution vs. Centralization

load might be a reason to
distribute a service

There are congested parts of the Internet today

oceanic links

peering points


provisioning may be easier if there are many sites

Service Economics

Composition: economics meets engineering

SLAs are an important part

Trust relations

Management tools for services

What are the ones required for composed services

Diagnose and isolate problems

Composition by user (dynamic) vs. composition by
service providers (less dynamic)