[nsp] 7505 / VIP 4-80 memory query

From: Thomas, Iwan (Iwan.Thomas@cwcom.cwplc.com)
Date: Tue Feb 26 2002 - 09:37:59 EST


Hi folks,

I'm stress-testing a 7505's throughput with a QoS service-policy applied
outbound on a POS STM-1 interface. I am seeing severe degradation of
throughput when compared to FIFO w/ no policy. Distributed CEF is on the
box, route-cache-distributed on the relevant interfaces.

With no policy applied, I can generate >100Mbps full-duplex, using 64-byte
packets (giving me >200,000 pps in each direction).
With the policy applied, I drop to 33Mbps, <70,000 pps. Note that no packets
are being queued or dropped according to my CBWFQ stats.

I'm trying to pin down where the bottleneck is most likely caused, without
going out and sourcing extra memory ;-) The VIP CPU memory is responsible
for implementing policing and assigning packets the correct DSCP marker (I
think). So am I right in guessing that an upgrade to 128MB would improve the
siuation, or am I missing something? Either way, a little advice/data on
the responsibilities of the separate memory portions of the VIPs and the RSP
would be appreciated.

Specs:

RSP4 (R5000 CPU at 200MHz) with 128MB DRAM and 2MB SDRAM.
2 x VIP 4-80 RM7000 with 64MB CPU SDRAM and 64MB Packet SDRAM.
2 x POS PA-POSSW-SM port adapters.
The POS links are on separate VIPs, running STM-1 direct to a traffic
generator.

Cheers,

Iwan

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