I have a case that I don't have a way to resolve this, can anyone help me to troubleshoot this problem ?
In my DC, I have a Catalyst Switch 4507 connect to one ZTE Switch using port-channel5. And Server Farm connect to 4507 via linecard 24port 1G.
The topology of network in this picture.
When I ping from another local Lan in difference subnet with Server Farm, The delay of packet is very high, and some time the ping reply request timeout,althought all link is GigabitEthernet 1Gb. The Catalyst 4507 connect to ZTE Switch using Interface port-channel5 with 6 bundle link, up bandwidth to 6Gb. Then I log to Catalyst 4507, using "show interface port-channel5" command, we see that drop packet in port-channel5. This is the result of show interface port-channel5
Port-channel5 is up, line protocol is up (connected)
Hardware is EtherChannel, address is 0019.e734.3f2f (bia 0019.e734.3f2f)
MTU 1522 bytes, BW 6000000 Kbit, DLY 10 usec,
reliability 255/255, txload 64/255, rxload 2/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, media type is N/A
input flow-control is off, output flow-control is unsupported
Members in this channel: Gi1/19 Gi1/20 Gi1/21 Gi1/22 Gi1/23 Gi1/24
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output never, output hang never
Last clearing of "show interface" counters 00:08:17
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 2960374
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 70075000 bits/sec, 88349 packets/sec
5 minute output rate 1509557000 bits/sec, 129272 packets/sec
48154520 packets input, 4601539612 bytes, 0 no buffer
Received 813 broadcasts (96 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 206 overrun, 0 ignored
0 input packets with dribble condition detected
70527852 packets output, 103036482692 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 output buffer failures, 0 output buffers swapped out
But with the same configuration, I replace Catalyst 4507 using Catalyst 3750G, the problem don't appear. Don't have a lose packet in port-channel5. All ping command reply succesfull and time of ping is <1ms.
When I test with topo in picture bellow.
The drop packet error eapear again in port-channel6. there no problem between Catalyst 3750G and ZTE Switch. Only Problem with Catalyst 4507. Alway have a drop packet in Catalyst 4507 but with the same configuration, there no problem with Catalyst 3750.
When I enable netflow on Catalyst 4507, the errors eapear "Netflow stats lost either due to hardware hash collisions or full hardware flow table. Stats lost". But in Catalyst 3750, nothing appear.
So what is the problem ???? Can anyone help me ???
Thanks very much,
The linecard WS-X4424-GB-RJ45 you are using works with oversubscription 4:1. It has 6 ASICs grouping the ports this way:
ASIC 1 --> Gi1/1 - Gi1/4
ASIC 2 --> Gi1/5 - Gi1/8
ASIC 3 --> Gi1/9 - Gi1/12
ASIC 4 --> Gi1/13 - Gi1/16
ASIC 5 --> Gi1/17 - Gi1/20
ASIC 6 --> Gi1/21 - Gi1/24
Each ASIC shares 1Gb uplink from the linecard to the backplane so, each 4-ports groups share 1Gb of bandwidth.
In your case you are suffering oversubscription on your ports.
If you want to eliminate the drops I will suggest creating the etherchannel with ports:
Gi1/1, Gi1/5, Gi1/9, Gi1/13, Gi1/17 and Gi1/21 for instance. Or any other combination using one port from each group.
The C3750 works at wire speed with no oversubscription, hence you do not have drops.
Hope this helps.