[acascianelli]

I'm trying to configure Etherchannel on AIX 5.3 and I'm having some problems. I am aggregating both of the onboard NIC's (ent0 and ent1) into a new adapter ent2 for failover reasons obviously. At first I was experiencing a problem where about 50% of all my packets would be dropped. Then after removing all the network devices and rediscovering and recreating the aggregate, it is much better but I am still losing about 1-2% of the packets.

I am assured that there is no problems with the switch configuration, and I have verified that both network cables are working properly.

I'm hoping that someone will point out something that I have missed in created the aggregate.

[kovacskrisztian]

Hello. Can u please copy the etherchannel configuration here, maybe it helps us...

[seth]

Please give us more information, what is the vendor of your switch (cisco?) Du you want to aggregate the links together (use both links for loadbalancing reasons) or do you want to make a netif-backup solution (2 adapters only one activ, if this fails the backupadapter takes over). How did you set up the etherchannel (exact description of smit menues)?

seth

[kovacskrisztian]

Seth i think he wanted not to aggregate, but make a failure-tolerant system, one interface is the backup of the other... but without infos we can't help him

[acascianelli]

Here is exactly what I did...

1) smitty etherchannel
2) Add an etherchannel / link aggregation
3) Select both of the onboard NIC's (ent0 + ent1)
4) I left all the options defaulted, a new ent2 is created
5) smitty chinet
6) Configure en2 with my IP information

...Like I said before, the setup seems to work fine but every 30-40 minutes there is a period that lasts anywhere from 10 - ~60 seconds where all network activity drops. Switch vendor is Cisco

Here is my etherchannel configuration...

# lsattr -El ent2
adapter_names   ent0,ent1      EtherChannel Adapters                       True
alt_addr        0x000000000000 Alternate EtherChannel Address              True
auto_recovery   yes            Enable automatic recovery after failover    True
backup_adapter  NONE           Adapter used when whole channel fails       True
hash_mode       default        Determines how outgoing adapter is chosen   True
mode            standard       EtherChannel mode of operation              True
netaddr         0              Address to ping                             True
noloss_failover yes            Enable lossless failover after ping failure True
num_retries     3              Times to retry ping before failing          True
retry_time      1              Wait time (in seconds) between pings        True
use_alt_addr    no             Enable Alternate EtherChannel Address       True
use_jumbo_frame no             Enable Gigabit Ethernet Jumbo Frames        True 

The original idea was to have the NIC's act as failover onto one another, but now that I know more about it I am interested in load balancing too.

[seth]

Here is a good description of the etherchannel modes you can choose and what each mode does: IBM Systems Information Center
I hope your network guys know that you make a etherchannel, due they have to set this up on the switch too to get it right.
I found this redbook on google, search it for "cisco" for details of how to configure the switch.

http://www.redbooks.ibm.com/redbooks/pdfs/sg246606.pdf

page 255 has some detail on the switch config.
The links on page 351 may provide more info, if they are not out of date by now. Usually your network admins should know this stuff...

Cheers seth

[acascianelli]

I found the problem...

I was configuring the controllers to act as a load balancing etherchannel controller. This normally would not be a problem, but I had each NIC connected to a different switch.

I removed the Etherchannel adapter and recreated a new one with a primary/backup failover configuration and it is working fine now.

[Administrator]

Forget load balancing. You don't have enough adapters.

Your configuration will only work if you are using one switch. Concatination is not supported across multiple switches, even if you have one of the few switches that allow it.

You should recreate your etherchannel with en0 being the only adapter and en1 as the backup adapter.

Each adapter should be cabled to different switches. Set your mode to 802.3ad.

This is the best overall configuration for the number of adapters you have for a redundant configuration.

[acascianelli]

Originally Posted by Administrator

You should recreate your etherchannel with en0 being the only adapter and en1 as the backup adapter.

Each adapter should be cabled to different switches. Set your mode to 802.3ad.

This is the best overall configuration for the number of adapters you have for a redundant configuration.

This is how I have it setup right now and it's working. However, I have the mode set to standard and not 802.3ad. What is the difference between the two?

[seth]

Originally Posted by acascianelli

This is how I have it setup right now and it's working. However, I have the mode set to standard and not 802.3ad. What is the difference between the two?

Just read the links I posted before, here an excerpt:

IEEE 802.3ad is a standard way of doing link aggregation. Conceptually, it works the same as EtherChannel in that several Ethernet adapters are aggregated into a single virtual adapter, providing greater bandwidth and protection against failures.
For example, ent0 and ent1 can be aggregated into an IEEE 802.3ad Link Aggregation called ent3; interface ent3 would then be configured with an IP address. The system considers these aggregated adapters as one adapter. Therefore, IP is configured over them as over any Ethernet adapter.
Like EtherChannel, IEEE 802.3ad requires support in the switch. Unlike EtherChannel, however, the switch does not need to be configured manually to know which ports belong to the same aggregation.
The advantages of using IEEE 802.3ad Link Aggregation instead of EtherChannel are that it creates the link aggregations in the switch automatically, and that it allows you to use switches that support the IEEE 802.3ad standard but do not support EtherChannel.



seth