linux bonding and dell switch

Question

I'd like to use mode 4 of the linux bonding ( mode4 = 802.3ad)

IEEE 802.3ad Dynamic link aggregation. Creates aggregation groups that share the same speed and duplex settings. Utilizes all slaves in the active aggregator according to the 802.3ad specification.

	Pre-requisites:
	1. Ethtool support in the base drivers for retrieving
	the speed and duplex of each slave.
	2. A switch that supports IEEE 802.3ad Dynamic link
	aggregation.
	Most switches will require some type of configuration
	to enable 802.3ad mode.

I'd like to know if I can use this configuration without problems with dell switch of the 27xx series.

Tnanks in andavance.

bh1633 · Answer

2700 switches do not support dynamic link aggregation (LACP).  They support static link aggregation.

crazyswitch · Answer

Thanks for replying. So from what I have understand from you post, bonding supports only dynamic link aggregation, right? So what are the right dell switches to do what i am looking for? Thanks again.

bh1633 · Answer

You can use the 2700 switches, you just have to configure linux to use static link aggregation.

Dell switches that support LACP (dynamic link aggregation) are the 3000, 5000, and 6000 series switches.

crazyswitch · Answer

Thanks againg for replying, now the last question, i hope :) How to set linux bonding to use static link aggregation?

bh1633 · Answer

Here's a link: http://www.cyberciti.biz/howto/question/static/linux-ethernet-bonding-driver-howto.php   Look at Bonding Driver Options.  Set the 'mode' to 'balance-xor'

crazyswitch · Answer

Hi, I have read the link you suggested me.

But I think it's not what I am looking for, I mean, I 'd like to do the folling thing:
to put, for examples, (number) two 1 gigabit network interfaces "together" so to have only one interface at the speed of 2 gigabit.

From what I have understand, I need this:

802.3ad or 4

                IEEE 802.3ad Dynamic link aggregation.  Creates
                aggregation groups that share the same speed and
                duplex settings.  Utilizes all slaves in the active
                aggregator according to the 802.3ad specification.

                Slave selection for outgoing traffic is done according
                to the transmit hash policy, which may be changed from
                the default simple XOR policy via the xmit_hash_policy
                option, documented below.  Note that not all transmit
                policies may be 802.3ad compliant, particularly in
                regards to the packet mis-ordering requirements of
                section 43.2.4 of the 802.3ad standard.  Differing
                peer implementations will have varying tolerances for
                noncompliance.

                Prerequisites:

                1. Ethtool support in the base drivers for retrieving
                the speed and duplex of each slave.

                2. A switch that supports IEEE 802.3ad Dynamic link
                aggregation.

                Most switches will require some type of configuration
                to enable 802.3ad mode.

Do I have understand right? (correct me please if what I'd like to do is impossible or if I have posted a wrong section of the link you provide me)

Do all this things are related to the "famous" LACP ?

So the question is can I do it with the 2007 series?

THANKS AGAIN.

crazyswitch · Answer

Using the mode you suggested me, In the switch I have to go in the menu called 'LAG Membership' and create a group or I have to do nothing? Thanks

bh1633 · Answer

You have to create the group on the LAG membership page.

crazyswitch · Answer

I have ordered the 2724!

Well, i have ordered two of them :)

I have understand that I can't use the "Mode 4" and you suggested me to use "mode 2".

Are there other "modes" I can use with this switch?

What's the most performant mode I can use with that switch?

Because of my bad english, I didn't uderstand exactly what "mode 2" does, I have only understand that provdes load balancing and fault tolerance. How does it work? I mean, there's a server with 4 port bonded in mode 2 with the switch.

If 2 computer attached to the switch ask 2 different files from the server, what happens? One file is sent through one interface of the server and the other file via the other interface of the server?

Thanks again :)

crazyswitch · Answer

thanks for replying!   What about the 'reverse street', i mean some clients that puts things on the server? Does it work on the same way of the 'server to client street?    So what about a situation of a server with 4 port bonded in mode 2 to the switch, and 15 computer attached to the switch asking files from the server?  Do you think it would be a good configuration?   So, the only mode I can use is mode 2?

Zitibake · Answer

Usually, all traffic from one MAC address (one server) to another MAC address (another server) takes the same link. So if Server1 has a 2-gig LAG to the switch, and sends two files to Server2, both will take the same 1 gig cable. If Server1 sends a file to Server2 and also to Server3, there is a 50% chance that both files will go over the same cable.

Load will be well balanced when there are many MAC addresses sending/receiving data over the LAG. If there are just two servers communicating, then all traffic will take just one cable in each direction.

Some switches can also balanace traffic based on IP address, TCP src/dest port, UDP src/dest port, etc., but usually only the layer-3 switches (e.g. 62xx) can do that. I think Dell added better balancing in the last couple of 53xx firmware versions, but in the 27xx switch, I would think that it will only balance traffic based on MAC address.

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linux bonding and dell switch

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