[j-nsp] Different media in an AE cause framing issues?

[Ben Boyd]

On Apr 1, 2013, at 15:52, Morgan McLean <wrx230 at gmail.com> wrote:

> Hey guys...
> 
> So I just bought a bunch of avago SFP+'s from a local distributor, about
> 250 of them, so I'm in relatively deep here.
> 
> I'm wondering if I just made a general mistake by adding another 20gbit of
> MM OM3 with these new modules to an existing 20gbit AE which is using DAC.
> I started noticing framing errors mostly on the two additional links I had
> added. It was around 100-300 per second per interface..the DAC interfaces
> were fine. The AE was only pushing around 1-2gbit duplex at the time when I
> noticed it (packet loss), and I shut down those interfaces.
> 
> I'm using these modules to convert existing top of rack connections from
> twinax/DAC to fiber, which I haven't started, but I DID just roll out
> another 8 cabinets using these modules, and so far I haven't seen any
> framing errors...but then again I'm not pushing much traffic. I also didn't
> see these issues when I tested a couple modules before we bought them...
> 
> The core AE is between two EX8208's, and the TOR connections are going out
> from the core to EX3300's.
> 
> Here are the stats for one of the cabinet AE's from the core switch side,
> which looks clean:
> 
> Interface: ae5, Enabled, Link is Up
> Encapsulation: Ethernet, Speed: 20000mbps
> Traffic statistics:                                           Current delta
>  Input bytes:                 264708836 (2040 bps)                  [1928]
>  Output bytes:               5520922123 (23832 bps)                [25257]
>  Input packets:                 2013442 (1 pps)                       [16]
>  Output packets:               35600334 (22 pps)                     [256]
> Error statistics:
>  Input errors:                        0                                [0]
>  Input drops:                         0                                [0]
>  Input framing errors:                0                                [0]
>  Carrier transitions:                18                                [0]
>  Output errors:                       0                                [0]
>  Output drops:                        0                                [0]
> 
> The EX3300 side looks good, as well as the AE for the VC between the
> 3300's, which also use these modules...
> 
> So at this point I'm wondering if mixing the fiber and DAC connections is a
> nono? Due to timing issues? Not sure how that would screw up the frame, but
> maybe somebody has more insight.
> 
> -- 
> Thanks,
> Morgan
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Although I've actually never done it, I've always assumed you could mix and match media types in an AE. I think you may be right, either mixing them is a no-no, or one/both of them are bad. 

Try replacing the DAC connections with SFP+ connections or turn up a new AE with only the new SFPs.