c2821#sh buf  
Buffer elements:
     597 in free list (500 max allowed)
     179623725 hits, 0 misses, 618 created

Public buffer pools:
Small buffers, 104 bytes (total 110, permanent 100, peak 112 @ 1w5d):
     96 in free list (20 min, 150 max allowed)
     105962055 hits, 22156 misses, 18961 trims, 18971 created
     4805 failures (0 no memory)
Middle buffers, 600 bytes (total 627, permanent 180, peak 627 @ 2d10h):
     130 in free list (10 min, 230 max allowed)
     33509571 hits, 4072 misses, 6733 trims, 7180 created
     938 failures (0 no memory)
Big buffers, 1536 bytes (total 35, permanent 50, peak 129 @ 7w0d):
     34 in free list (5 min, 150 max allowed)
     47069174 hits, 2236 misses, 899 trims, 884 created
     1365 failures (0 no memory)
VeryBig buffers, 4520 bytes (total 10, permanent 10, peak 14 @ 4w4d):
     9 in free list (0 min, 100 max allowed)
     757297 hits, 811 misses, 220 trims, 220 created
     801 failures (0 no memory)
Large buffers, 5024 bytes (total 1, permanent 0, peak 3 @ 7w0d):
     1 in free list (0 min, 10 max allowed)
     277 hits, 524 misses, 774 trims, 775 created
     524 failures (0 no memory)
Huge buffers, 18024 bytes (total 1, permanent 0, peak 3 @ 4w4d):
     1 in free list (0 min, 4 max allowed)
     144 hits, 422 misses, 791 trims, 792 created
     422 failures (0 no memory)

Interface buffer pools:
Syslog ED Pool buffers, 600 bytes (total 132, permanent 132):
     100 in free list (132 min, 132 max allowed)
     276565 hits, 0 misses
CD2430 I/O buffers, 1536 bytes (total 0, permanent 0):
     0 in free list (0 min, 0 max allowed)
     0 hits, 0 fallbacks
IPC buffers, 4096 bytes (total 2, permanent 2):
     1 in free list (1 min, 8 max allowed)
     1 hits, 0 fallbacks, 0 trims, 0 created
     0 failures (0 no memory)

Header pools:
Header buffers, 0 bytes (total 768, permanent 768):
     256 in free list (128 min, 1024 max allowed)
     512 hits, 0 misses, 0 trims, 0 created
     0 failures (0 no memory)
     512 max cache size, 512 in cache
     444400 hits in cache, 0 misses in cache

Particle Clones:
     1024 clones, 11824222 hits, 0 misses

Public particle pools:
F/S buffers, 256 bytes (total 768, permanent 768):
     256 in free list (128 min, 1024 max allowed)
     11436178 hits, 0 misses, 0 trims, 0 created
     0 failures (0 no memory)
     512 max cache size, 512 in cache
     11824222 hits in cache, 0 misses in cache
Normal buffers, 1548 bytes (total 768, permanent 768):
     768 in free list (128 min, 1024 max allowed)
     94297 hits, 0 misses, 0 trims, 0 created
     0 failures (0 no memory)

Private particle pools:
HQF buffers, 0 bytes (total 2000, permanent 2000):
     2000 in free list (500 min, 2000 max allowed)
     0 hits, 0 misses, 0 trims, 0 created
     0 failures (0 no memory)
IDS SM buffers, 240 bytes (total 128, permanent 128):
     0 in free list (0 min, 128 max allowed)
     128 hits, 0 fallbacks
     128 max cache size, 128 in cache
     0 hits in cache, 0 misses in cache
GigabitEthernet0/0 buffers, 1536 bytes (total 384, permanent 384):
     0 in free list (0 min, 384 max allowed)
     384 hits, 206 fallbacks
     384 max cache size, 256 in cache
     2978833324 hits in cache, 206 misses in cache
GigabitEthernet0/1 buffers, 1536 bytes (total 384, permanent 384):
     0 in free list (0 min, 384 max allowed)
     384 hits, 0 fallbacks
     384 max cache size, 256 in cache
     1809819441 hits in cache, 0 misses in cache
FastEthernet0/0/0 buffers, 1548 bytes (total 128, permanent 128):
     0 in free list (0 min, 128 max allowed)
     128 hits, 94091 fallbacks
     128 max cache size, 64 in cache
     4064949932 hits in cache, 94027 misses in cache
NETGX_CACHE_BUFFERS buffers, 1700 bytes (total 256, permanent 256):
     0 in free list (0 min, 256 max allowed)
     256 hits, 0 fallbacks
     256 max cache size, 256 in cache
     0 hits in cache, 0 misses in cache

> Доброго времени суток!
> На интерфейсе с какой-то периодичностью появляются ошибки, растолкуйте, из-за чего они
> появляются, и как с ними бороться? Маршрутизатор c2821.

Смирись.
В пики траффика бывают ситуации, когда роутер слишком занят, чтобы обработать пакет, или переполнены все буферы. Если на скорость не влиеяет и в коредамп не валится - все нормально.