[j-nsp] EX Feedback

[Chuck Anderson]

On Fri, Jul 24, 2009 at 03:05:23PM +0400, Alexandre Snarskii wrote:
> Just a note: that 128Gbps looks to me like a 'true marketing number', 
> because of what ex-series show in cli is 32Gbps: 
> 
> snar at Switch> show interfaces vcp-0    
> Physical interface: vcp-0, Enabled, Physical link is Down
>   Type: 105, Link-level type: 70, MTU: 1514, Speed: 32000mbps
> 
> Well, there are two virtual-chassis interfaces, and they have
> both input and output directions, and 32G * 2 * 2 is really 128Gbps
> of marketing... 
> 
> Or am I wrong, and virtual-chassis really can do 128Gbps full-duplex 
> on both ports ? And, anyway, 32Gbps is still better than 10Gbps
> and saves uplink ports. 

You are right.  The rear VC ports are PCI-Express 2.0 x8 ports, giving 
500 Mbytes/sec/lane * 8 lanes * 8 bits/byte = 32 Gbps per direction 
[1].

[1] http://en.wikipedia.org/wiki/PCI_Express