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wrong interface couters on cisco7600 with 12.2(18)SXF ?

mogli
Level 1
Level 1

Hi

we found very confusing interface outputs on a c7600.

following scenario:

a cisco 7600 with sup 720 and 12.2(18)SXF has an physical interface (gig4/2) which is configured as access-port in vlan 112. it's the only port which resides in vlan 112

(vlan is neither configured on another access-port or a trunk).

when having a look at the interface stats (of gig4/2 and vlan 112) they should be nearly the same (?). every packet that runs over the vlan interface (and is counted there)

should be counted an the gig4/2 too. for layer2 traffic the interface-counter should only increase on the physical interface (gig4/2). so the counter on the physical

interface should be equal or greater than the counter on the vlan interface?

up to now, are my considerations right, or is there an error in reasoning?

and now look at the couters i found:

7600#sh int vlan 112

Vlan112 is up, line protocol is up

Hardware is EtherSVI, address is 000b.45b6.8680 (bia 000b.45b6.8680)

Internet address is 192.168.1.1/30

.

.

.

30 second input rate 9050000 bits/sec, 5131 packets/sec

30 second output rate 66276000 bits/sec, 10415 packets/sec

L2 Switched: ucast: 199695 pkt, 14435395 bytes - mcast: 3 pkt, 192 bytes

L3 in Switched: ucast: 7303812279 pkt, 1615356566364 bytes - mcast: 0 pkt, 0 bytes mcast

L3 out Switched: ucast: 7616662247 pkt, 5034856698175 bytes mcast: 0 pkt, 0 bytes

7304180311 packets input, 1615389381107 bytes, 0 no buffer

Received 1 broadcasts (0 IP multicasts)

0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

15233681478 packets output, 10039288913936 bytes, 0 underruns

0 output errors, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

7600#

7600#

7600#

7600#

7600#sh int gigabitEthernet 4/2

GigabitEthernet4/2 is up, line protocol is up (connected)

Hardware is C6k 1000Mb 802.3, address is 000e.8400.41a7 (bia 000e.8400.41a7)

MTU 1500 bytes, BW 100000 Kbit, DLY 10 usec,

reliability 255/255, txload 98/255, rxload 29/255

Encapsulation ARPA, loopback not set

.

.

.

Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 48606

Queueing strategy: fifo

Output queue: 0/40 (size/max)

30 second input rate 8279000 bits/sec, 4740 packets/sec

30 second output rate 33207000 bits/sec, 5141 packets/sec

7304184055 packets input, 1615389797781 bytes, 0 no buffer

Received 1786 broadcasts (1781 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

7618085026 packets output, 5034985411859 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

7600#exit

"

The "packets input" are almost equal - in my point of view I would trust these couters. But having a look the "packets output"

there are about twice as much packets on the vlan interface. The same factor is on the 30 second "in-/output rate" values.

I already cleared the interface counters - the values change but the factor 2 between the 30 seconds output rate on the logical and the physical interface is still the

same.

has anyone already noticed such an couter mismatch between logical and physical interfaces? i'm not saying that this is a bug, and if it isn't a bug, can somebody explain

the counter differences to me?

thanks a lot for your help,

kind regards

1 Reply 1

s-doyle
Level 3
Level 3

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