1. Next steps for SPP & ONL 2/6/2007
Jon Turner

2. Objectives for SPP-NPE version 2
Deal with constraints imposed by switch
can send to only one NPU; can receive from only one NPU
split processing across NPUs
parsing, lookup on one; queueing on other
Provide more resources for slice-specific processing
Decouple QM schedulers from links
collection of largely independent schedulers
may use several to send to the same link
e.g. separate rate classes (1-10M, M, M)
optionally adjust scheduler rates dynamically
Provide support for multicast
requires addition of next-hop IP address after queueing
Enable single slice to operate at 10 Gb/s

3. NPE Version 2 Block Diagram
Lookup produces resultIndx, statsIndx
slice#, resultIndx passed in shim
SRAM Tx
(2 ME)
TCAM
Decap, Parse, Lookup, AddShim
(8 MEs)
Stats
(1 ME)
from switch Rx
flow control?
large scratch ring
SRAM
to switch
Queue Manager
(4 MEs) Rx
(2 ME) Tx
Lookup &Copy
HdrFmt
Stats
(1 ME)
large scratch ring
for unicast, resultIndx replaced by QiD; allowing output side to skip lookup
Lookup on <slice#, resultIndx> yields fanout, list of QiDs; copy to queues, adding copy#; (slice#, resultIndx remain in packet buffer)
use slice# to select slice to format packet; use resultIndx to get next-hop

4. Statistics LC provides counts on UDP ports
Matching filter gives slice-specific stats-index which is updated for each packet handled by filter
Pre-queue/post-queue counters for each QiD
Memory space/bandwidth issues
off-chip SRAMs support 200M 32 bit reads & writes per sec
can have 16M 80 byte packets/sec, so one SRAM supports 12 reads/12 writes per packet
for 250 byte packets, 36 reads/36 writes per packet
updating stats for QiD takes 4 reads/4 writes

5. Objectives for ONL Router
Reproduce approximately same functionality as current hardware router
routes, filters (including sampling filters), stats, plugins
Extensions
multicast, explicit-congestion marking
Use each NPU as separate 5 port router
each responsible for half the external ports
xScale on each NPU implements CP functions
access to control variables, memory-resident statistics
updating of routes, filters
interaction with plugins through shared memory
simple message buffer interface for request/response

6. fanout, 10 bit copy vector, QiD, resultIndx
ONL NP Router
fanout, 10 bit copy vector, QiD, resultIndx Rx
(2 ME)
HdrFmt
(1 ME)
Parse, Lookup, Copy
(3 MEs)
TCAM
SRAM
Mux Tx
Queue Manager
Stats
Plugin
SRAM
xScale
large scratch ring
Each output has common set of QiDs
Multicast copies use same QiD for all outputs
QiD ignored for plugin copies
large scratch ring