Is Lambda Switching Likely for Applications? Tom Lehman USC/Information Sciences Institute December 2001

2 Context/Time Frames Far Future (10 yrs+) –New end system architectures which can source/sink 80Gb/s+ –Large availability of fiber which can support >1000’s lambda’s per fiber Near Future (5-10 yrs) –Improvements in existing end system architecture –Must live with/use large amounts of non-dispersion compensated fiber currently in place –Following slides will focus on this time frame

3 Network Component Considerations Before we discuss network architectures, protocols, and features, lets evaluate what we can expect from the components in this time frame –End Systems –Routers & Switches –Optical capacity

4 End System/Router/Switch Performance (order of magnitude) Currently –2 GHz processors, 128 bit => 250 Gbit/s processing power –250 MHz SRAM, 128 bit => 32 Gbit/s memory bandwidth –133 MHz PCIx, 64 bit => 8 Gbit/s I/0 bandwidth –Router/Switch Interfaces => 10 Gbit/s Near Future? –10 Ghz processors, 128 bit => Terabit/s processing power –1 GHz SRAM, 128 bit => 128 Gbit/s memory bandwidth –QDR 133 MHz PCIx, 64 bit => 32 Gbits/s –Infiniban12x => 24 Gbit/s (per full duplex channel) –Router/Switch Interfaces =>40 Gbit/s

5 Optical Capacity (order of magnitude) Currently –C Band spacing => 64 lambda’s/fiber –10 Gbit/s/lambda => 640 Gbits/s/fiber Near Future –80 Lambda’s/fiber –40 Gbit/s lambda => 3.2 Terabits/s/fiber –80 Gbit/s lambda => 6.4 Terabits/s/fiber End Systems and Router/Switch interfaces will not keep up with the increase in optical speeds –Moore’s law will not allow processor speeds to keep up –End system architecture (complicated OS and protocol stack and slow I/O) will prevent matching speeds –Router switch interfaces beyond 40 Gbit/s will be a challenge (electronic components do not yet exist for those speeds, so gap between optics and electronics will get larger)

6 Assumption on Component Capabilities End Systems –Source/sink 24 Gbit/s –End system modifications may include Direct host memory to NIC card dma features Complete offload of protocol stack to hardware Router/Switch Interfaces –40 Gbit/s Optical Capacity (per fiber) –80 Gbit/s => 3.2 Terabits/s/fiber

7 Is Lambda Switching Likely for Applications? No, in the context of end to end lambda switching between applications across the network on a widescale –not enough lambda’s for this to scale –Special applications (e-Science?) may require end to end lambda’s Yes, in the context of an interface or network connection which provides real time capacity provisioning based on application requests –this could be part of overall QOS scheme –(some) circuit/lambda switched in the core, IP on the edges Networks need to be able to support widescale deployment of “fast” end systems and also provide guaranteed QOS –Lambda switching could be a key enabling technology

8 Network Issues Networks need to provide applications with on demand guaranteed QOS. This should include: –ability for applications to discover/query in real time end to end performance –ability to be guaranteed a level of “performance” on and end to end basis IP Networks –packet switched networks good for bursty traffic and applications which can live with best effort delivery. –not so good for long flows which require guaranteed performance –currently no well working mechanisms for guaranteed QOS in IP networks. DiffServ, RSVP, MPLS, IntServ Circuit switched networks provide QOS, but did not scale well.

9 GMPLS a solution? GMPLS may be heading in the right direction –allows MPLS to control multiple devices such as LSRs, SONET ADMs, OADMs, OXCs Allows network to utilize benefits of packet switched and circuit switched networks. Bulk of traffic should still be packet switched on an end to end basis Circuit switched lambda’s could be used for provisioning based on aggregation of application demands Special applications (e-Science?) may require end to end lambda’s

10 GMPLS Architecture IP Router Lambda Switch IP is the control plane for setting up “layer 2 circuits”

11 QOS in this Environment The packet switched QOS should be simpler –just guarantees bandwidth? –applications which use this can compensate for loss and jitter (including VOIP) Circuit switched QOS guarantees bandwidth, delay, jitter But the same issues that have yet to be solved regarding QOS still need resolution –What is the economic model? Who pays? –How is it enforced? –The monitoring, enforcement, and accounting must be simple. –How is this accomplished across domains? an ability to create “layer 2” circuits across domains may help this