[j-nsp] MX and microbursting...

[Derick Winkworth]

I was thinking of just applying a shaping-rate at the port level.  As it stands 
not more than 300m or so could ever pass through this interface (based 
ultimately on the sum of the interfaces the traffic is routing to at the WAN 
edge).  


It turns out actually there is an EX-4200 between the MX and the 7200.  So I'm 
thinking of just applying a port-level shaper on the EX at 400m or 500m.  
Flow-control is a no go.





________________________________
From: "sthaug at nethelp.no" <sthaug at nethelp.no>
To: dwinkworth at att.net
Cc: juniper-nsp at puck.nether.net
Sent: Mon, April 11, 2011 1:13:08 PM
Subject: Re: [j-nsp] MX and microbursting...

> I have tuned up buffers and hold-queues on the 7200 and this has drastically 
> reduced the number of dropped packets, but still there is this rx-ring 
> limitation.  This is actually a fairly well known issue as I understand it.
> 
> Is there anything I could do on the MX to control the microbursting outbound 
> towards the 7200? 

You might be able to do something with Ethernet flow control - I don't 
remember if the NPE-G2 can send pause frames. However, most likely you
have to do shaping on the MX. Shaping can buffer and smooth out bursts.
Obviously, to do this it has to *delay* some packets.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no