[j-nsp] Ping RTD behaviour

[Gary Tate]

Just to add to this - echo requests are given the lowest priority so 
that any routing updates packets, management packets etc are processed 
first and are placed in a higher priority Q than echo replies.

Gary

Gary Tate wrote:
> When you ping the router R2 you are sending packets to the Routing 
> Engine.  R2 has queues from the forwarding plane (PFE) to the control 
> plane (RE).  Then the reply needs to be processed by the  RE and then 
> sent back to the PFE (Queued again).  The link between the RE and the 
> PFE is FastEther.  This is where the extra delay is probably introduced
> 
> The server/switch is probably a faster path than the PFE-RE one.
> 
> Gary
> 
> Abdelhamid TIBERDANI wrote:
> 
>> Hi all
>>
>> Can someone help understanding the following ping RTD behaviour, the 
>> RTD is
>> always better beween R1 and the SERVER than between R1 and R2 (directly
>> connected)
>>
>> R1
>> -------------------------------R2--------------------Switch-----------------
>> ----SERVER
>> 10.0.0.1            10.0.0.2
>> 20.0.0.2
>>
>> When I perform a ping test between R1 ip@10.0.0.1  to R2 ip@10.0.0.2 the
>> RTD is :round-trip min/avg/max/stddev = 0.818/0.865/0.968/0.043 ms
>>
>> When I perform a ping test between R1 ip@10.0.0.1  and the SERVER
>> Ip@20.0.0.2 the RTD  is always better , round-trip min/avg/max/stddev =
>> 0.533/0.578/0.679/0.052 ms
>>
>> Regards
>> Abdel
>>
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> 
>