You’re welcome — it’s nice to be able to help others.
Using CIFS sharing, with one GbE link I got around 40 MBytes/sec, and with trunking enabled using two GbE links I’m getting around 80 MBytes/sec.

About your trunking efforts:
I’m not surprised that having link aggregation at one end (solaris), but not the other end (switch) of your link appears to work. Each transmitted frame is an atomic operation on each end of the link: The sender does what he will, and the receiver tries to make sense of it. My bet is that Solaris was trunking, and that the MAC address table on your switch was being constantly thrashed.

When you get trunking fully supported, I don’t think you’re going to see benefits between a single pair of computers. The trunking mechanisms go to great lengths to not allow frames within a flow to be mis-ordered. A flow is usually defined by the 5-tuple: src_ip, dst_ip, protocol, src_port, dst_port. …But the particulars are configurable. Frame mis-ordering is accomplished by assigning a flow to a particular link, and making sure that all frames in the flow are sent over the same link.

Note that the link chosen by the switch doesn’t have to match the link chosen by the server because they balance the links independently.

When your fileserver is performing bulk transfers to or from multiple systems you might see a throughput benefit. If not, then the benefit is limited to link redundancy.

/chris

Thanks for the info — I think I saw the other day that one of the links on the Mac or Solaris box didn’t appear to have flow control enabled, so I will take a closer look at that. Cheers.

Also, around the same kind of price, I’ve seen a Linksys (now Cisco) switch: the SLM2008, which also appears to support IEEE 802.3ad for Link Aggregation. I don’t know how these 2 switches compare with each other, but I might take a read.

I see also there is a Linksys SRW2008 switch, which seems about twice the price.

If I really want to checkout Link Aggregation then I’ll need to get something like one of these switches that supports IEEE 802.3ad.

For now, I’ve destroyed the aggregated link and returned to NWAM with a single Gigabit ethernet link.

Now I’ve seen aggregation though, I am tempted to get one of those IEEE 802.3ad compliant switches as they’re quite inexpensive for a prosumer model like the first two mentioned above — something like $100 / €100.

I too have two Gb ethernet ports and have looked at aggregating them. The switch I’m considering is the Netgear G108T which is a smart switch and claims to support link aggregation. For the prosumer it looks to be at the correct price point - unless you can get hold on a Cisco at a good price that is!

with both ethernet cables attached to the switch:
# dladm show-link
LINK CLASS MTU STATE OVER
nge0 phys 1500 up –
nge1 phys 1500 up –
aggr1 aggr 1500 up nge0 nge1

now disconnect nge0 cable:
# dladm show-link
LINK CLASS MTU STATE OVER
nge0 phys 1500 down –
nge1 phys 1500 up –
aggr1 aggr 1500 up nge0 nge1

I still have a usable connection (I can surf), so it’s now using nge1 — or the ether

now plug nge0 cable back in and pull out nge1 cable from the switch:
# dladm show-link
LINK CLASS MTU STATE OVER
nge0 phys 1500 up –
nge1 phys 1500 down –
aggr1 aggr 1500 up nge0 nge1

I can still surf, so it’s using nge0.

So the redundancy/fail-over aspect of the aggregated link is working.

When I think of a heavy enough test to really stress the link I will see if it’s using both links or not — will probably need some network monitoring tool to to see the figures…

It has separate entries for 802.3x and 802.3ad:
* 802.3x: Full Duplex and flow control; also incorporates DIX framing, so there’s no longer a DIX/802.3 split
* 802.3ad: Link aggregation for parallel links

From this, it seems that my switch doesn’t support link aggregation, as it only mentions “802.3x Flow control” in the specs and not “802.3ad Link aggregation”. Oh well, never mind, aggregation was never a requirement when buying the switch, just something that occurred to me later. But it’s interesting to know these things for possible future projects.

But my question is, does link aggregation always rely on the hardware — i.e. the switch, or can it be done in software using the OS, in this case Solaris?

From these pages, it seems like the switch definitely needs to support link aggregation:
http://blogs.sun.com/droux/entry/link_aggregation_vs_ip_multipathing
http://blogs.sun.com/droux/entry/link_aggregation_plumbing

I have a DLink DGS-1008D green ethernet 8-port Gigabit switch - see here:
ftp://ftp.dlink.eu/datasheets/DGS-1008D.pdf

Of relevance, perhaps, in this data sheet it says it supports “IEEE 802.3x Flow control”, which I assume covers IEEE 802.3ad, which appears to be what’s required for link aggregation / port trunking:
http://en.wikipedia.org/wiki/Link_aggregation

Does this look like this switch should support link aggregation to you?

Here’s additional info from their website:

* 8 10/100/1000 Mbps Gigabit ports on Cat. 5
* 16Gbps switching fabric
* Auto MDI/MDIX cross over for all ports
* Secure store-and-forward switching scheme
* Full/half-duplex for Ethernet/Fast Ethernet speeds
* Blazing 2000Mbps full duplex for Gigabit speed
* IEEE 802.3x Flow Control
* Plug-and-play installation
* Easily installable on desktop

Furthermore, you should be aware that there are to commonly-used types of link aggregation and both ends should be using the same method. They are static and dynamic (802.1ad protocol). I’m not sure which kind is in use here because I’m not yet familiar enough with Solaris. It’s worth pointing out that many cheaper switches which support trunking/aggregation only support static mode. I’ve been bitten by this when trying to create a trunked connection from some of my SAN storage units or XServes, which only support the 802.1ad dynamic trunking.