[j-nsp] MX80 L2TP Functions

[Richard A Steenbergen]

On Fri, Jun 11, 2010 at 04:25:54PM +1000, Julien Goodwin wrote:
> Have a look at the hardware guide, it's out now (finally...).
> 
> The MX80 is four XFP slots (30Gbit bandwidth), plus two MIC slots for
> interfaces, all "Trio 3D" based. Alternately the two MIC slots can be
> replaced by 48 10/100/1g copper ethernet ports (40Gbit bandwidth)

The way it was explained to me is like this: The Trio PFE can normally
do 30Gbps of "forward facing capacity" and 30Gbps of "fabric facing
capacity", which is how the PFE works on the MPC cards. On the MX80
there is only a single PFE, and thus no fabric to interconnect multiple
PFEs together, so what they've done is remap it into 60Gbps of forward
facing capacity. I don't *think* there are any components which apply
any bandwidth restrictions to any group of ports (i.e. 30Gbps across the
4xXFP ports), just the overall Trio bandwidth limit, but the last time I
asked even Juniper didn't know exactly how much bandwidth the Trio chips
would do. :)

Even on the MPC cards Trio can do some local switching which doesn't
count towards the fabric utilization, but from what I've heard it seems
like there may be a lot of "gotchas" (for example, supposedly doing
egress filtering breaks local switching, etc). If all the Trio cards 
weren't so damn backordered I would have a much better idea of the 
performance by now. :)

> Bad news from the hardware guide is that the RE is poor. 1.2Ghz CPU
> and 2Gb of ram (not 100% if it can be expanded, looks so), but in a
> nod to the EX4200 two 4GB *fixed* storage drives on the board. The RE
> is also not a separate board from the base.

Not "that" poor, it's a 1.2GHz PowerPC, which is roughly the performance
of a p4 3GHz. I haven't looked at it in detail yet, but I'd say odds are
good its the exact same integrated CPU/RE that is used on the EX8200 RE
(which is also the same cpu that is used on the original MX DPCs). On
the EX RE the ram and flash are not expandable, so you may be SOL there. 

I REALLY don't know what Juniper is thinking by shipping boxes with such
limited storage, but at least 4GB flash on MX80 isn't as disastrous as
the 2GB flash on EX8200 (where there is so little storage you can't
write a core dump from a large rpd process). 

-- 
Richard A Steenbergen <ras at e-gerbil.net>       http://www.e-gerbil.net/ras
GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)