[c-nsp] Traffic shaping on a GE interface

[George Manousakis]

I am facing a problem in a network and I would like some suggestions in
order to solve it (and to understand it as well)!!

 

The case is that I use GE interfaces on cisco devices as wan links but on
the other side there are elements providing EoSDH services. Those elements
do not operate as Ethernet routers and switches regarding (at least) the way
that they buffer packets, resulting drops.

 

For example, I have a wan link of 300Mpbs and at both ends the interfaces
are Optical GE on cisco routers (7200 or ASR). Because of the multiplexing
done on the wan link provider the CIR on the GE port is only 300mbps, so
whenever cisco is bursting traffic (which seems perfectly normal since the
clock rate on the interface dictates 1Gbps rate), the other side is dropping
packets. I tried using traffic shaping (300mbps with default values for
buckets Be and Bc) on the outside flow on both cisco interfaces but the
result is the same. Maybe the dropping rate is reduced, but there are still
packet drops.

 

These drops are appearing only on the provider equipment, on both ports.

 

How can I configure the MCQ in order to suppress the transmission rate on
the wan capability??? I want to transmit no more that 300mbps under any
condition! Using traffic shaping should solve that problem but because of
the unpredictable characteristics of the traffic on the wan bursts may occur
that are above 300Mbps. 

 

I have to comment that that the average traffic on the interface is less
than 200mbps. The problem is caused (I assume) by  the bursts in the
fragments of a second that GE can support but EoSDH cannot allow.

 

Thanks in advance.