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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Tail Drops and TCP Slow Start
If I have a DS3 or OC3 handling mounds and mounds of FTP download traffic,
what is the easiest way to detect if the bandwidth in use is falling into
a classic Tail Drop pattern? According to a Cisco book I am reading, the
bandwidth utilization should graph in a "sawtooth" pattern of gradual
increases in accordance with multiple machines gradually increasing
via TCP slow start and then sharp drops. Will this only happen when
the utilization approaches 100%. (maybe dumb question)
Should I be able to do a show buffers and see misses or is there some
better way to detect other than via graphing?
Also, suppose in examining my ftp traffic patterns that I noticed that it
spikes at 15minutes after the type of the hour, consistently, etc.
Could I create a timed access list to only kick in at that time?
Anyone have experience with WRED to handle ftp congestion?
I usually take these types of questions to Cisco but I thought I'd post
it to this list to get any generic real world advice.
sh buff
Buffer elements:
499 in free list (500 max allowed)
5713661 hits, 0 misses, 0 created
Public buffer pools:
Small buffers, 104 bytes (total 600, permanent 600):
580 in free list (20 min, 1250 max allowed)
2225528470 hits, 6 misses, 18 trims, 18 created
0 failures (0 no memory)
Middle buffers, 600 bytes (total 450, permanent 450):
448 in free list (10 min, 1000 max allowed)
68259213 hits, 7 misses, 21 trims, 21 created
0 failures (0 no memory)
Big buffers, 1524 bytes (total 450, permanent 450):
449 in free list (5 min, 1500 max allowed)
6807747 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
VeryBig buffers, 4520 bytes (total 50, permanent 50):
50 in free list (0 min, 1500 max allowed)
46167681 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
Large buffers, 5024 bytes (total 50, permanent 50):
50 in free list (0 min, 150 max allowed)
0 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
Huge buffers, 18024 bytes (total 5, permanent 5):
5 in free list (0 min, 65 max allowed)
34 hits, 6 misses, 12 trims, 12 created
0 failures (0 no memory)
Interface buffer pools:
IPC buffers, 4096 bytes (total 768, permanent 768):
768 in free list (256 min, 2560 max allowed)
769236774 hits, 0 fallbacks, 0 trims, 0 created
0 failures (0 no memory)
Header pools:
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