topic Re: APA modes in Operating System - HP-UX

APA modes

UniRock — Fri, 29 Jan 2010 02:58:17 GMT

Hello All..

In Auto Port Aggregation
load balance : multiple NICs balance load
failover mode : one NIC will work at a time

Is this correct?
Is there any OTHER difference between "load balance" & "failover mode" in APA apart from what the names suggest?

Thanks

Re: APA modes

Kapil Jha — Fri, 29 Jan 2010 03:19:16 GMT

Yes you are correct.
in aggregation if u have 4 NICs then all 4 NIC balance the load.
and in failover one NIC would be working at a time and other would take up if first goes down.

http://docs.hp.com/en/J4240-90046/J4240-90046.pdf
Chapter 1 has information in details :)

BR,
Kapil+

Re: APA modes

Jupinder Bedi — Fri, 29 Jan 2010 07:04:56 GMT

Yes , you are 100% correct . This is the only difference.

Re: APA modes

UniRock — Fri, 29 Jan 2010 07:21:18 GMT

Thanks for your replies.

Suppose I have configured a node in "load balance mode" with 2 NIC. One fails, so only one will be working?
If this is the case, then this type of policy will be serving both functionalities (balance + failover).

Hence, can we come to conclusion that "load balance mode" is ALWAYS better and preffered/recommended ??

Re: APA modes

Jupinder Bedi — Fri, 29 Jan 2010 07:28:02 GMT

Ye , you are again right , if you will configure as a load balance and one of the network card gets failed than another card will take care . mostly we use failover technique if we have 4 nic cards . pair of 2 n/w cards cards with act as load balance and than 2+2 will act as failover

Re: APA modes

Horia Chirculescu — Fri, 29 Jan 2010 07:47:48 GMT

Hello,

From APA Admin's guide,

"HP APA link aggregates can migrate the network traffic from a failed physical link in the aggregate to the remaining operational links in the aggregate"

I believe this explain this situation.

Best regards,
Horia.

Re: APA modes

UniRock — Fri, 29 Jan 2010 12:48:14 GMT

Thanks again for your replies.

Few more queries.
1. If I have 2 NIC cards, should I go with load balance only?
2. Is Link Aggregate same term used for Load Balanacing??
3. What is Lan Monitor?

Re: APA modes

rick jones — Sat, 30 Jan 2010 01:14:18 GMT

Lest there be any confusion - "balance the load" will balance the *outbound* traffic based on the packet scheduling algorithm you select. And any one "flow" will only travel over a single link in the aggregate. What constitutes a "flow" will depend on the packet scheduling algorithm you select - one defines a flow as a source/destination MAC (ethernet) address pair, one defines it as a source/destination IP address pair, a third defines it as the four-tuple of source/destination IP plus source/destination port number.

Further, *inbound* trafic balancing will be a function of the _switch_ and the choices made there.

Re: APA modes

UniRock — Mon, 15 Feb 2010 13:43:41 GMT

Hi All,

Some questions still unanswered:

1. What is Link Aggregate? Is it same term for Load Balancing?

2. What is Lan Monitor?

I tried looking around but still confused.

Re: APA modes

rick jones — Tue, 16 Feb 2010 18:33:30 GMT

A link aggregate is a collection of two or more links aggregated together into a single logical interface. In other contexts you will hear it called a trunk, or a bond, or a team.

LAN Monitor is an active/standby mode in APA whereby one has both active and inactive (standby) links and if the active link(s) fail traffic is shifted to the standby links.