Transcript Challenges in the Next Generation Internet

Challenges in the Next
Generation Internet
Xin Yuan
Department of Computer Science
Florida State University
[email protected]
http://www.cs.fsu.edu/~xyuan
• Internet Traffic doubles each year.
• Backbone traffic growth [Odlyzko01]:
– 100% per year from 1990 – 1994.
– 1000% per year in 1995 and 1996.
– 100% per year in 1997 through 2000.
• Internet is becoming more and
more ubiquitous.
• More commercial applications.
• More multimedia applications.
• The Next Generation Internet will meet
all these challenges:
• Large bandwidth through the optical DWDM
(Dense Wavelength Division Multiplexing)
technology.
• multi-service.
– service differentiation (Quality of Service).
• Security
• How to expose the large bandwidth to
applications?
IP over WDM: protocol stack
IP
IP
ATM
SONET
WDM
WDM-aware
Electronic layer
WDM
• IP over WDM: WDM-aware electronic
layer:
–
–
–
–
–
Reconfiguration and load balancing.
Protection and restoration
Optical switching
Network management/control
Cross-layer optimizations
• IP over WDM: Protection and restoration.
– When a link is down, services should not be
interrupted for too long.
• One optical link supports a large number of flows.
• SONET detects failure in 2-100us, restores
operation in 60 ms.
– Need to extend the SONET model to deal with
the general mesh networks.
– Determine the backup path together with the
main path (more complex in routing).
– How to utilize the capacity effectively?
• IP Quality of Service:
– To control the network service response so that
is is predictable.
– To allow the client to establish in advance the
service response that will be obtained from the
network.
– To control the contention for network
resources.
– To allow for efficient total utilization of
network resources.
• IP Quality of Service: models
– Integrated Service (IntServ):
• End to End QoS guarantee (What users want)?
• Too many states for each router to maintained (not
scalable).
• Cannot be deployed incrementally.
– Differentiated Services (DiffServ):
• Define PHB (per hop behavior).
• Each router distinguishes 64 queues (scalable).
• End-to-end QoS by provisioning?
– Stateless QoS model:
• Carrying QoS information at each packet.
• IP Quality of Service: other issues
– Packet scheduling: FIFO does not work
anymore.
• Fair queuing is quite expensive.
– Routing:
• Taking QoS metrics into consideration can make it
very difficult
• Scalable QoS routing for large networks can be
hard.
• Exposing hardware performance to
applications.
– Different applications result in different traffic
patterns.
• Special communication optimizations can be
performed by considering (1) the communication
pattern and (2) the underlying network architecture.
– Compiled communication for Message Passing
Interface (MPI) programs over clusters of
workstations.
• Compiled Communication:
– Traditional communication optimization:
• In the compiler:
– Reducing the size and volume of communications.
– Architecture independent optimizations.
• In the library:
– Architecture dependent optimizations.
– Don’t know the sequence of communications in
applications.
– Compiled communication:
• Compiler knows the sequence of communications in
applications and the network architecture.
• Can perform architecture dependent optimizations
across communication patterns.
MPI_Scatterv(…)
…
MPI_Scatterv(…)
MPI_Open_Group(…)
MPI_Data_Move(…)
MPI_Close_Group(…)
…..
MPI_Open_Group(…)
MPI_Data_Move(…)
MPI_Close_Group(…)
MPI_Open_Group(…)
MPI_Data_Move(…)
…..
MPI_Data_Move(…)
MPI_Close_Group(…)
• Compiled Communication: How to make it
happen?
– Traditional communication libraries do not
support this communication model (easy to use
is the main goal).
• Compiled communication capable MPI library:
– Should allow the compiler (user) to management network
resources
– In our prototype:
» Compiler can manage multicast group.
» Compiler can schedule the communications (for
collective communications).
– Need a compiler that can do the analysis.