Пару дней назад загрузка cpu внезапно выросла до 99%:

Router7206#sh proc c s
CPU utilization for five seconds: 99%/99%; one minute: 99%; five minutes: 99%
PID Runtime(ms)   Invoked      uSecs   5Sec   1Min   5Min TTY Process
  81      331464    235552       1407  0.24%  0.25%  0.24%   0 IP Input        
   2       21444      2046      10480  0.08%  0.21%  0.21%   0 Load Meter      
  19       15128     40110        377  0.08%  0.01%  0.00%   0 ARP Input        
  76      159456   1437786        110  0.08%  0.00%  0.00%   2 Virtual Exec    
   1          12        94        127  0.00%  0.00%  0.00%   0 Chunk Manager    
   3           0         1          0  0.00%  0.00%  0.00%   0 chkpt message ha
   4           0         1          0  0.00%  0.00%  0.00%   0 EDDRI_MAIN      
   5      209432      6024      34766  0.00%  0.05%  0.02%   0 Check heaps      
   6          36        19       1894  0.00%  0.00%  0.00%   0 Pool Manager    
   7           0         2          0  0.00%  0.00%  0.00%   0 Timers          
  
Конфигурация не менялась, трафик небольшой (~50Mbit).
На одном из портов на входе ~ 1% ошибок:
Router7206#sh int gi0/3
GigabitEthernet0/3 is up, line protocol is up
  Hardware is MV64460 Internal MAC, address is 0023.ac8f.6419 (bia 0023.ac8f.6419)
  MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
     reliability 254/255, txload 1/255, rxload 6/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 1000Mb/s, media type is RJ45
  output flow-control is XON, input flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:00, output 00:00:00, output hang never
  Last clearing of "show interface" counters 00:57:24
  Input queue: 0/75/17347/16 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 26481000 bits/sec, 76830 packets/sec
  5 minute output rate 202000 bits/sec, 152 packets/sec
     265031715 packets input, 2829425222 bytes, 0 no buffer
     Received 34546 broadcasts, 0 runts, 0 giants, 0 throttles
     2064346 input errors, 0 CRC, 0 frame, 0 overrun, 2064346 ignored
     0 watchdog, 34810 multicast, 0 pause input
     0 input packets with dribble condition detected
     518395 packets output, 87945950 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     58 unknown protocol drops
     147 unknown protocol drops
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 pause output
     0 output buffer failures, 0 output buffers swapped out

С ip cef вроде всё нормально:
Router7206#sh int switching
...
GigabitEthernet0/3
          Throttle count          0
                   Drops         RP      53446         SP          0
             SPD Flushes       Fast         18        SSE          0
             SPD Aggress       Fast          0
            SPD Priority     Inputs      40808      Drops          0

    Protocol  IP                  
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process      21271    2952188      20668    2788215
            Cache misses          0          -          -          -
                    Fast  802454708  219625028    1334765  222910464
               Auton/SSE          0          0          0          0

    Protocol  Trans. Bridge      
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process       4310     258600        390      24960
            Cache misses          0          -          -          -
                    Fast      31121    3235355      51168    8442957
               Auton/SSE          0          0          0          0

    Protocol  DEC MOP            
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process          0          0         17       1309
            Cache misses          0          -          -          -
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0

    Protocol  Spanning Tree      
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process      13308     829332      15575    1059100
            Cache misses          0          -          -          -
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0

    Protocol  ARP                
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process      38852    2333788     131909    7922536
            Cache misses          0          -          -          -
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0

    Protocol  CDP                
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process          7       4466         48      22128
            Cache misses          0          -          -          -
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0

    Protocol  Other              
          Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                 Process        141      13618       1046      62760
            Cache misses          0          -          -          -
                    Fast          0          0          0          0
               Auton/SSE          0          0          0          0

    NOTE: all counts are cumulative and reset only after a reload.
....

Router7206#sh ip traffic
IP statistics:
  Rcvd:  813346698 total, 51914 local destination
         0 format errors, 2 checksum errors, 216900 bad hop count
         0 unknown protocol, 2489 not a gateway
         0 security failures, 0 bad options, 0 with options
  Opts:  0 end, 0 nop, 0 basic security, 0 loose source route
         0 timestamp, 0 extended security, 0 record route
         0 stream ID, 0 strict source route, 0 alert, 0 cipso, 0 ump
         0 other
  Frags: 0 reassembled, 0 timeouts, 0 couldn't reassemble
         218 fragmented, 440 fragments, 0 couldn't fragment
  Bcast: 8511 received, 996 sent
  Mcast: 0 received, 0 sent
  Sent:  132969 generated, 812950999 forwarded
  Drop:  222778 encapsulation failed, 0 unresolved, 0 no adjacency
         707 no route, 0 unicast RPF, 796 forced drop
         0 options denied
  Drop:  0 packets with source IP address zero
  Drop:  0 packets with internal loop back IP address
         136 physical broadcast

ICMP statistics:
  Rcvd: 6 format errors, 7 checksum errors, 0 redirects, 36 unreachable
        1589 echo, 0 echo reply, 0 mask requests, 0 mask replies, 0 quench
        0 parameter, 0 timestamp, 1755 timestamp replies, 0 info request, 0 other
        0 irdp solicitations, 0 irdp advertisements
  Sent: 0 redirects, 0 unreachable, 26 echo, 1589 echo reply
        0 mask requests, 0 mask replies, 0 quench, 1770 timestamp, 0 timestamp replies
        0 info reply, 215271 time exceeded, 0 parameter problem
        0 irdp solicitations, 0 irdp advertisements

TCP statistics:
  Rcvd: 20130 total, 0 checksum errors, 513 no port
  Sent: 21273 total

UDP statistics:
  Rcvd: 26660 total, 1 checksum errors, 25961 no port
  Sent: 296 total, 0 forwarded broadcasts

Router7206#show ip interface
....
GigabitEthernet0/3.1 is up, line protocol is up
  Internet address is XXX
  Broadcast address is 255.255.255.255
  Address determined by non-volatile memory
  MTU is 1500 bytes
  Helper address is not set
  Directed broadcast forwarding is disabled
  Outgoing access list is not set
  Proxy ARP is disabled
  Local Proxy ARP is disabled
  Security level is default
  Split horizon is enabled
  ICMP redirects are never sent
  ICMP unreachables are never sent
  ICMP mask replies are never sent
  IP fast switching is enabled
  IP fast switching on the same interface is enabled
  IP Flow switching is disabled
  IP CEF switching is enabled
  IP Feature Fast switching turbo vector
  IP Feature CEF switching turbo vector
  IP multicast fast switching is disabled
  IP multicast distributed fast switching is disabled
  IP route-cache flags are Fast, CEF
  Router Discovery is disabled
  IP output packet accounting is disabled
  IP access violation accounting is disabled
  TCP/IP header compression is disabled
  RTP/IP header compression is disabled
  Policy routing is enabled, using route map ISP
  Network address translation is enabled, interface in domain inside
  BGP Policy Mapping is disabled
  WCCP Redirect outbound is disabled
  WCCP Redirect inbound is disabled
  WCCP Redirect exclude is disabled
...

Куда копать? Уже всё перепробовал. Похоже на аппаратные проблемы.