Re: [tsvwg] Switch testing at 25G with ECN --SCE Draft

[Greg White <[e-mail]>]

Right.  Per the SCE method, the switch would mark ECT(1) using a ramp, and then when the ramp would exceed 100% marking, it would change to using CE.  

The implementation discussed here marks CE using a ramp, and when the ramp would exceed 100% marking, it changes to packet drop.  This, as you said, is simply RFC3168 ECN marking, not SCE ECN marking.

I was just trying to set the record straight.  There was a claim made that a switch vendor had implemented SCE-style packet marking in hardware at 25Gbps, which wasn't accurate.

-Greg



On 8/9/19, 2:58 PM, "Jonathan Morton" <[e-mail]> wrote:

    > On 9 Aug, 2019, at 11:44 pm, Scaglione, Giuseppe <[e-mail]> wrote:
    > 
    >>> Just to be super clear, this isn't a hardware implementation of SCE running at 25Gbps.
    > 
    > I am not sure I follow. The Test setup section of the paper clearly describes the hardware used -- severs, switch, cables. 
    > What I cannot disclose at this point is the exact model and characteristics of the HPE Aruba Switch used. Yet, it is a "real" Ethernet Switch, providing 25Gbps connectivity, configured to do bridging across the four ports and implementing RFC3168 with the ECN remarking configuration described in my previous email and on the paper.
    
    I think the issue is with the way the switch itself marks with CE, not ECT(1).  It's a limitation I think is worth acknowledging and, hopefully, finding a way to remove.
    
     - Jonathan Morton