Transcript Survey of Active network

Active Network
• A Survey of Active Network Research
• Direction in Active Networks
• Protocol Boosters : Applying
Programmability to Network Interfaces
指導老師 - 鍾添曜
06-01-1999
871775
顧凌峰 / 871772
陳桂慧
Survey of Active network
• Active networks are a novel approach to
network architecture in which
– The switches and the routers of the network perform
customized computations on messages flowing through
them .
• Take a look at fig.1
– Nodes can perform computation on ,and modify,the packet
content.
– This process can be customized on a per-user or perapplication basis.
Index
The emergence of Active network……………………………………. 3
Accelerating Infrastructure innovation……………………………….. 4
Enable new application……………………………………………….. 5
A Framework active network research……………………………….. 6
Architecture overview………………………………………………… 9
Composite network services………………………………………….. 13
Application…………………………………………………………… 16
Protocol booster………………………………………………………. 17
FZC booster implementation …………………………………………19
Conclusion……………………………………………………………. 20
Current research………………………………………………………. 21
§The Emergence of Active Network
The concept from discussion of within the broad Defense Advanced
Research Project agency (DARPA) research community In1994~1995.
Several problem occur with today`s network :
—Difficulty with integrate new technology into shared infrastructure
—Poor performance due to redundant operation at several protocol layer
—Difficulty accommodating new services in present architecture model
Several strategies emerged to address these issue called active network
§Accelerating Infrastructure innovation
Lead user : some new services
Firewall,Web proxy,Nomadic router ,Transport gateway
Today,the path from from prototype demonstration to large-scale
deployment takes about ten years.
However,Active node can execute many different programs
—In the past,the networking industry devoted to bundle Hardware and
Software together,and active network change this innovation.
—Network programming abstraction provides a powerful platform for
user-driven customization of the infrastructure(user could program).
§Enable New Application
Merging and Distribution of information
Merging data can reduce the bandwidth ;user-specific multicast
reduce the load on the sensor and network backbone (FIG.2)
User-aware network protection
Active network may admit the design of an integrated mechanism
this eliminate multiple authentication independently of each layer.
Active network management
§A Framework for Active Network Research
Programmable switch-a discrete approach
— User first inject their custom processing routines into the required
routers(programmable node).
— When a packet arrive a node ,they examine its header ,and the
appropriate program is dispatched to operate on its contents.
Capsules - An Integrated Approach(every message is a program )
—First identifies capsule boundaries,possibly using framing scheme —
The capsule`s content are then dispatched to a transient execution
environment
—
with some built-in primitives which provide to access resource external
to transient execution
Architecture
• Common base functionality of node architecture
– how packets are processed
– what resource are available at that node
– how they are assessed
• Execution Environment (EE)
• Node Operating System (NodeOS)
• Fig 1, Fig 2.
EEs = “shell” program in a general-purpose computing
system, providing an interface through which end-to-end
network services are provided to user.
The NodeOS implements
communication channel,
over which EEs send and
receive packet.
The request is accompanied by an
identifier for the principal in whose
behalf the request is made.
controlled by a pattern
specified by the EE when
it creates the channel.
Schedule only
for computation
Schedule for both
computation and
transmission
Architecture(cont’)
• Active Network Encapsulation Protocol (ANEP)
– The ANEP header includes a type identifier field; types
ID are assigned to specific EEs.
• Interfaces and Standardization
– EE-NodeOS interface need not be identical from node to
node; all that is required is for each node to provide a
standard set of basic services to EEs.
– User-EE interface mainly involve encodings that must be
understood by both the end user and the NodeOS
Composite Network Services
• Goal of active networks
– to ease the deployment of new services.
• An important support feature of a network API
– ability to compose services from building blocks.
– the building blocks for network services as components.
– A network API contains a composition mechanism used to
create a composite service from component.
Composition Mechanisms
• Choice from a set of options
– selects a predefined computation at the network node.
• Turing-complete programming language
– components can be install in the active node as Java
subroutines.
• Special-purpose language for composition
– a restricted language specifically design for services
creation can be used to compose network services.
• Event-based framework
– dynamic behavior can be incorporated into composition
by structuring the composition as an event-driven
computation and ”binding” code modules to specific.
Composition Mechanisms(cont’)
• Service composition in LIANE,
(language- independent active network environment)
– underlying program
– injected program used to customize the
underlying program
Application - Caching
• Static hierarchy
– administrative burden
– limiting the ability to react to dynamic conditions.
• Reduce network traffic and response time.
– where to locate object.
– how to forward request between caches.
Protocol booster ——
Applying programmability to network infrastructure
— It allows dynamic and efficient protocol customization to
heterogeneous environments.
§The two limitations of TCP/IP
—They evolve more slowly than the changes in networking tech and
application requirements.
— They trade some loss for their ability to handle in efficiency with the
increased heterogeneity.
§ Why protocol booster
— It is the need for protocol adaptation and programmability,then
generate protocol booster .
— For example,when on a LAN the protocol would adjust itself to give
performance similar to that of a specialized LAN protocol.
Properties for Fig.1
using booster nesting
host X,Y don`t know about the existence of booster
multiple element booster
single booster can monitor protocol messages to and from message
stream
ex.hide retransmission in a application required low-lantency
§Practical Example the FZC(forward EraZure correction)booster
It is a multiple element booster
It reduces the effective packet loss rate on noisy link,by FEC.
Fig.2
at transmitter add h1 parity packets ,and the receiver recover from
up to h1 packets erasures.
§ Conclusion
—Active network involve the synthesis and extension of programming
language ,operating systems ,and networking expertise
— Protocol booster are a ideal application for an on-the-fly(dynamic)
programmable network infrastructure
— In place of protocol stack ,application may use protocol components
that can be specialized and composed to perform application-specific
function
§Current research
—Massachusetts Institute of Technology(M.I.T)
Prototyping an architecture based on the capsule approach
—University of Pennsylvania
Developing a programmable switch approach that allows digitally signed
type -checked modules to be loaded into the nodes
— Bell communication research
several aspects of the Penn design will be studied jointly with Bell core
,but using different infrastructure(OPCV2)
— Columbia university (it`s a agent)
“Net script” provide a mean to script the processing of packet stream
— Carnegie Mellon University (CMU)
developing resource management in support of application aware