Transcript Document

Hardware Accelerated
Signaling and its
Application in Fast
Network Restoration
Prof.Veeraraghavan
Prof.Karri
Haobo Wang: [email protected]
Background

What’s signaling?
 Signaling
protocols are used in connection-oriented
networks to set up and tear down connections.

Primarily implemented in software
 Complexity
and the requirement for flexibility
 What we pay is the performance

Hardware accelerated signaling
 Why?
100x-1000x speedup
 How? FPGA+Hardware/software Codesign
Which is better?

“Thin” hardware signaling engine
 Simple
signaling addressed to single application
 Optical Circuit Signaling Protocol – OCSP
 Simple, for SONET network only

Hardware accelerated signaling engine
 “Panacea” signaling – RSVP-TE for GMPLS
 Complex but covers all connection-oriented networks
 Hardware/Software


Codesign
Time-Critical functions->hardware
Non-Time-Critical functions->software
Network and node view
Architecture of Prototype Board
To Host
PCI Bus
FPGA (Xilinx XC2V40)
PCI Bridge
O/M
(HFCT
53D5)
SERDES
(HDMP
-1636)
GbE
MAC
(L8104)
Hardware
Signaling
Accelerator
TCAM
(MT75W8Y136H)
SRAM
(MT55L64L36P1)
Switch Fabric
(VSC9182)
On-Board Bus
Hardware Signaling Accelerator
GbE Interface
RAM
(Message Buffer)
PCI
Bridge
Object Dispatcher/
Assembler
TCAM
Interface
Register Bank
OP*
* Object Processor
OP
OP
SRAM
Interface
Applications of Hardware signaling

High throughput


Support large scaled core switches – TCP switching
Low call setup delay
 Fast




restoration after network fails
Illinois, May 1988, a fire at a local exchange center
caused the loss of service to 35,000 residential
telephones
Today, data traffic prevails, more sensitive to loss
One single fiber may carry T(era)bps of user traffic!
Network survivability is essential
Trade-off of different recovery schemes

Resource utilization

Resource reserved in advance
Slow
Good
Restoration

react to failure dynamically

Mesh networks

Path switching
LAPS or SHR
Line switching


Bad
Linearly/Ring topology


Recovery delay
Protection


Fast
The failure is addressed
locally, point-to-point

The failure is addressed
globally, end-to-end
We want both! High resource utilization and low recovery delay

Dynamic re-routing in mesh networks
Dynamic re-routing in Mesh network

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A disjoint back-up route is pre-calculated, but not
allocated
Routing table has entries for backup route
Hardware signaling helps to set up backup path rapidly
May be blocked 
F
E
A
D
B
C
Analysis and simulation (ongoing work)


A 13-node, 22-link
sample network,
average number of
hops on primary path
is 2.4, on secondary
path is 3.5.
Analysis of dynamic
provisioning (M/D/1/∞)
Tsig  E (h)(Tsig 
Tsig
2(1  Tsig )
Tsig )
• Simulation of dynamic re-routing
• When link/node fails, all affected paths must be re-routed
simultaneously. We use OPNET to model the dynamic rerouting behavior.