Various ping result from adjacent router

[prananta]

Why do I get various ping result from an adjacent router (1-48 ms)? is this normal? these 2 router is directly connected with optical cable on Gigabit port with utilization below 30%

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Success rate is 100 percent (10000/10000), round-trip min/avg/max = 1/1/48 ms

GigabitEthernet2/1/21 is up, line protocol is up (connected)
  Hardware is C6k ---, address is --- (bia ---)
  Description: ---
  Internet address is ---/30
  MTU 1500 bytes, BW 1000000 Kbit, DLY 200 usec,
     reliability 255/255, txload 1/255, rxload 26/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 1000Mb/s, media type is LH
  input flow-control is off, output flow-control is off
  Clock mode is auto
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:00, output 00:00:02, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/15147/15147 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 104029000 bits/sec, 24960 packets/sec
  5 minute output rate 25000 bits/sec, 27 packets/sec
  L2 Switched: ucast: 1410510472 pkt, 125662125247 bytes - mcast: 43413945 pkt, 4650633929 bytes
  L3 in Switched: ucast: 843702795876 pkt, 509635610212001 bytes - mcast: 0 pkt, 0 bytes mcast
  L3 out Switched: ucast: 124878 pkt, 35139855 bytes mcast: 0 pkt, 0 bytes
     845161242376 packets input, 509766719103220 bytes, 0 no buffer
     Received 47866777 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 0 multicast, 0 pause input
     0 input packets with dribble condition detected
     95683097 packets output, 9075980776 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     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

[Joseph W. Doherty]

Normal? Often yes. Cisco devices treat replying to pings as a low priority task, it's also generally handled in software, not hardware.

BTW, 30% utilization means the link is busy 100% 30% of the time. Notice your input queue stats show ingress drops, which indicates an occasional queue (which also occasionally overflows) of ingress packets. I.e. ingress processing delay.