Mikrotik in the DFZ (Was Re: AW: AW: /27 the new /24)

Fri Oct 9 12:33:57 UTC 2015

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Hello William,

Le 03/10/2015 10:23, William Waites a écrit :
> I wish it were possible today to run different software on their 
> larger boxes. If some like-minded small providers wanted to get 
> together with us to fund a FreeBSD port to the CCR routers that
> would be great. Please contact me off-list if you are interested in
> this, I'll coordinate.

One of my contacts has worked on a similar path, and we encountered
many issues that makes it quite difficult.

Here is what I gathered, while I never had no access to the
NDA-covered material.

The Tilera architecture and its SDK is a great way to start such
project but Mikrotik didn't just use an off-the-shelf chip as
recommended, they also made slight changes to how the network
interfaces operates, and didn't provide any documentation.

It's not as easy as swapping a driver and rebuild a kernel, more like
changing how the programmable logic in Tilera's interface blocks
dispatch frames among the core's interconnexion grid.

Also, the cores are not fully compliant with MIPS specifications,
aren't combined as an SMP assembly at all (rather a NUMA grid with
added glue logic) and you can't even load the first instruction at 0x0
without using Tilera's own proprietary init code to allocate
ressources, initialize cores and setup the multiple "containers" (kind
of hardware virtualization).

So it's not quite about porting an OS than it has to do with tight
coupling of proprietary control code, bare-metal and FPGA logic, and a
specific data-plane implementation.

Still, the attempts have gone as far as booting a cutom linux kernel
spanned among a single CPU instance made of all 36 cores, but it has
no access to the network interfaces on the mikrotik board.

It does, however, work flawlessly on Tilera's developpment boards and
appliances, though neither the Linux kernel's data plane or
DPDK-derived code are yet able to take advantage of the specificities
of Tilera's architecture.

Nevertheless, if you want do get deeper and have enough motivation to
get past the technical difficulties, I'd gladly try to help into
bringing an alternative OS to these box.

Best regards,

- -- 
Jérôme Nicolle
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