[c-nsp] Load balancing on Portchan.

[Tóth András]

Hi,

The input and output rate being 0 on port-channel is caused by
software defect CSCsz18634 and it's fixed in 12.2(53)SE and later.


I would recommend to review the following documentations for more
details and examples about etherchannel load balancing.

Understanding EtherChannel Load Balancing and Redundancy on Catalyst Switches
http://www.cisco.com/en/US/tech/tk389/tk213/technologies_tech_note09186a0080094714.shtml

Load Balancing and Forwarding Methods
http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_55_se/configuration/guide/swethchl.html#wp1275731

Best regards,
Andras


On Fri, Jul 29, 2011 at 6:32 AM,  <mb at adv.gcomm.com.au> wrote:
> Hi,
>
> Have 2 100Mb eth ports in portchan, and 1 port seems to be doing all the
> receiving:
>
> sh interfaces fastEthernet 0/1
> FastEthernet0/1 is up, line protocol is up (connected)  Hardware is Fast
> Ethernet, address is f4ac.c17d.af83 (bia f4ac.c17d.af83)
>  Description: FEC_TO_ESW01_P20
>  MTU 1998 bytes, BW 100000 Kbit, DLY 100 usec,     reliability 255/255,
> txload 165/255, rxload 217/255
> ...  5 minute input rate 85322000 bits/sec, 13875 packets/sec
>  5 minute output rate 65048000 bits/sec, 12044 packets/sec
>
> FastEthernet0/2 is up, line protocol is up (connected)  Hardware is Fast
> Ethernet, address is f4ac.c17d.af84 (bia f4ac.c17d.af84)
>  Description: FEC_TO_ESW01_P21
>  MTU 1998 bytes, BW 100000 Kbit, DLY 100 usec,     reliability 255/255,
> txload 52/255, rxload 2/255
> ...
>  5 minute input rate 871000 bits/sec, 229 packets/sec
>  5 minute output rate 20396000 bits/sec, 3718 packets/sec
>
>
> The portchan doesnt report any usage(reports packets/bytes etc just not data
> rate or tx/rx)) for some reason on the 3560(the 2950 does though)
>
> #sh int port-channel 2
> Port-channel2 is up, line protocol is up (connected)  Hardware is
> EtherChannel, address is f4ac.c17d.af84 (bia f4ac.c17d.af84)
>  Description: FEC_TO_ESW01_BNE
>  MTU 1998 bytes, BW 200000 Kbit, DLY 100 usec,     reliability 255/255,
> txload 1/255, rxload 0/255
>  Encapsulation ARPA, loopback not set
>  Keepalive set (10 sec)
>  Full-duplex, 100Mb/s, link type is auto, media type is unknown
>  input flow-control is off, output flow-control is unsupported  Members in
> this channel: Fa0/1 Fa0/2  ARP type: ARPA, ARP Timeout 04:00:00
>  Last input 16:49:20, output 00:00:00, output hang never
>  Last clearing of "show interface" counters 16:31:53
>  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 670097
>  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
>    654778461 packets input, 542298725539 bytes, 0 no buffer
>    Received 576270 broadcasts (124103 multicasts)
>    0 runts, 0 giants, 0 throttles
>    0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
>    0 watchdog, 124103 multicast, 0 pause input
>    0 input packets with dribble condition detected
>    1141651151 packets output, 665041631494 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
>
> ...
>
> Any suggestions on how to balance the traffic better?
>
> switches are 3560+2950
>
> Thanks in advance.
>
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