Mag Gam on 22 May 2008 06:05:48 -0700

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Re: [PLUG] NIC bonding

Thanks for the responses. I am planning to setup a high performance network for my school as a summer project. High availability isn't my requirement but bandwidth is my primary concern. We have professors running peptide synthesis. Each model can easily output files large as .5-1TB and they move the files around on the LAN. Seems I will go with mode4.

Now I have to decide which filesystem I must use for sharing. I suppose NFS.

On Wed, May 21, 2008 at 11:43 PM, Glenn Kelley <> wrote:



It is pretty easy – however on the switch side you want to mirror the ports.

This helped us a great deal.


Failing to do this and … it's a pure bugger to say it lightly.

For more information – follow this link: 


For those of you wondering:

(copied from the net… in tons of places)






Bonding is the same as port trunking.  When/Why should you use port trunking / bonding?    Anytime you require redundant links, fault tolerance or load balancing it is wise to use port trunking.  If you can – use a 802.1q VLAN


There are a few bonding modes: 

Diverse modes of bonding:

mode=1 (active-backup)
Active-backup policy: Only one slave in the bond is active. A different slave becomes active if, and only if, the active slave fails. The bond's MAC address is externally visible on only one port (network adapter) to avoid confusing the switch. This mode provides fault tolerance. The primary option affects the behavior of this mode.

mode=2 (balance-xor)
XOR policy: Transmit based on [(source MAC address XOR'd with destination MAC address) modulo slave count]. This selects the same slave for each destination MAC address. This mode provides load balancing and fault tolerance.

mode=3 (broadcast)
Broadcast policy: transmits everything on all slave interfaces. This mode provides fault tolerance.

mode=4 (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.

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

mode=5 (balance-tlb)
Adaptive transmit load balancing: channel bonding that does not require any special switch support. The outgoing traffic is distributed according to the current load (computed relative to the speed) on each slave. Incoming traffic is received by the current slave. If the receiving slave fails, another slave takes over the MAC address of the failed receiving slave.

  • Prerequisite: Ethtool support in the base drivers for retrieving the speed of each slave.

mode=6 (balance-alb)
Adaptive load balancing: includes balance-tlb plus receive load balancing (rlb) for IPV4 traffic, and does not require any special switch support. The receive load balancing is achieved by ARP negotiation. The bonding driver intercepts the ARP Replies sent by the local system on their way out and overwrites the source hardware address with the unique hardware address of one of the slaves in the bond such that different peers use different hardware addresses for the server.
Also you can use multiple bond interface but for that you must load the bonding module as many as you need.



From: [] On Behalf Of Mag Gam
Sent: Wednesday, May 21, 2008 9:54 PM
To: Philadelphia Linux User's Group Discussion List
Subject: [PLUG] NIC bonding


I am planning to implement Ethernet bonding at my university. Does anyone have any experience with this? What are some problems you faced? Is it worth the hassle? Did you have to configure anything on the switch side? Did you do anything special with your switch such as MAC address modifications?


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