All Strix Halo systems have two USB4 v1 ports (40GBit/s) that are also Thunderbolt 3 compatible.

There doesn't seem to be routing with thunderbolt-net, so with two USB4 ports you can directly connect three Strix Halo systems for now. You can of course try to use other means to cluster more systems, like the Ethernet ports or connecting Infiniband Adapters via M.2 slots.

You need cables that can handle 40 GBit/s. The cheapest cables that are known to work are "_UGOURD Thunderbolt 40gbps_" that you can usually get for less than $5 each at 0.3m length from AliExpress. Good luck!

Note that the popular Sixunited AXB35 board has one USB4 port on the front and one on the back.

Bonding is using multiple network interfaces to get higher throughput, kind of like RAID for harddisks. There is a pending [kernel patch](https://lore.kernel.org/netdev/20251215121109.4042218-1-mika.westerberg@linux.intel.com/T/#t) that will allow bonding with thunderbolt-net. Until then it won't work.

The Llama.cpp RPC architecture is [explained in the documentation](https://github.com/ggml-org/llama.cpp/blob/master/tools/rpc/README.md). The version of Llama.cpp provided by [kyuz0s toolboxes](https://github.com/kyuz0/amd-strix-halo-toolboxes) are compiled with this option _enabled_.

Run `rpc-server` (part of llama.cpp) on all but one PC. It will make available your iGPU to the master PC. Use the `-c` option to make it cache the LLM data on the local disk (in the directory `~/.cache/llama.cpp/rpc/`). This will speed things up considerably on subsequent invocations of the same LLM.

On the **master** PC, you start `llama-server` with the `--rpc` option and provide it with the addresses of the other PCs. If you use Thunderbolt networking, make sure to give the addresses of the Thunderbolt interfaces.

1. Master PC with thunderbolt0 interface and IPv4 address 192.168.230.1

2. Second PC with thunderbolt0 interface and IPv4 address 192.168.230.2

On the master PC start `llama-server` as usual, but add the parameter `--rpc 192.168.230.2:50052`. If you have three PCs, add the third PC with a comma as separator: `--rpc 192.168.230.2:50052,192.168.230.3:50052`.

For further discussion join the [#beyond128g](https://discord.com/channels/1384139280020148365/1455307501472976979) discord channel.