11-01-2011 11:34 AM - edited 03-07-2019 03:09 AM
we have a setup 6500-------> 2970
Not much traffic on a trunk but we have quite a lot of input drops on 2970
but the input drops dissapears if i disable keepalives
can someone help me out with this ?
6506 interface :
interface FastEthernet3/15
switchport
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 45
switchport mode trunk
switchport nonegotiate
no ip address
no logging event link-status
load-interval 30
speed 100
duplex full
no snmp trap link-status
FastEthernet3/15 is up, line protocol is up (connected) Hardware is C6k 100Mb 802.3, address is 0012.dafe.85be (bia 0012.dafe.85be) Description: SRC=VL-MO-RI009-Fas3-15, DST=VL-DV-SG001-Gig0-24 MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Full-duplex, 100Mb/s input flow-control is off, output flow-control is unsupported ARP type: ARPA, ARP Timeout 04:00:00 Last input 00:00:32, output 00:00:01, output hang never Last clearing of "show interface" counters 2w3d Input queue: 0/2000/165204/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/40 (size/max) 30 second input rate 0 bits/sec, 0 packets/sec 30 second output rate 0 bits/sec, 0 packets/sec 809897 packets input, 478719601 bytes, 0 no buffer Received 50975 broadcasts (37132 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 3045538 packets output, 247983738 bytes, 0 underruns 0 output errors, 0 collisions, 0 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
2970 configuration:
interface GigabitEthernet0/24
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 45
switchport mode trunk
switchport nonegotiate
no ip address
duplex full
speed 100
no mdix auto
GigabitEthernet0/24 is up, line protocol is up (connected) Hardware is Gigabit Ethernet, address is 0011.92c6.e498 (bia 0011.92c6.e498) Description: SRC=VL-DV-SG001-Gig0-24, DST=VL-MO-RI009-Fas3-15 MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Full-duplex, 100Mb/s input flow-control is off, output flow-control is off ARP type: ARPA, ARP Timeout 04:00:00 Last input 00:00:01, output 00:00:05, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 2806097 packets input, 228508296 bytes, 0 no buffer Received 2430932 broadcasts (0 multicast) 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 watchdog, 2212762 multicast, 0 pause input 0 input packets with dribble condition detected 762370 packets output, 463878259 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
11-01-2011 07:58 PM
Please clear the counters once and run the command 'sh int fa3/15" few times to see if the input queue drops increment. From the output
Input queue: 0/2000/165204/0 (size/max/drops/flushes); Total output drops: 0
there seems to be no packet clogged in the queue currently.
The system counts input queue drops if the number of packet buffers allocated to the interface is exhausted or reaches its maximum threshold. You can increase the maximum queue value with the hold-queue
Refer to this link as well. This will highlight more on the input queue drops.
http://www.cisco.com/en/US/products/hw/routers/ps133/products_tech_note09186a0080094791.shtml
Cheers
Sweta
Please rate the useful posts.
11-02-2011 10:39 AM
Thanx for getting back to me Sweta
The thing is there is no traffic passing through the interface so there should not be any input Queue and there should not be any input drops and the input drops dissappear when i disable keepalives.
By default keepalives are for 10sec and for ethernet interfaces, keepalives are sent to the same interface to check if the interface is alive and for every 1 min i see 6 input drops which represents that all the keepalives are dropping.
and i see drops only on 6500 end not on 2970.
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