[j-nsp] Massive ICMP test. Could it generate problems?

[Gary Tate]

The B-Chip is an ASIC which has channels which have bandwidth. Each 
channel has queues that will limit bases on you CoS configuration.

As far as fragmentation goes the b-chip does not need protection from 
the RE as you cannot ping enough traffic from the RE to cause the 
b-chip any problems.

I am not an expert on the inner workings of the b-chip so you should 
contact the JTAC if you have any further queries.

Gary

On Dec 10, 2003, at 6:56 AM, mark at glassbil.net wrote:

> Almost done here ;-)
>
> I think i have it figured out but still one question remains.
> How will the b-chip handle the fragmentation during high load?
>
> If you don´t ping with a size bigger then the MTU the packet
> will only be proccesed by the CPU - re to linecard. But if you as i 
> said
> before add a paket size the b-chip will be used. Is the resources of 
> the
> b-chip also protected?
>
> Best Regards
> Mark
>
>> To be clear on this point:
>>
>> Sourced from the RE pings are limited via queuing mechanisms on the
>> fxp1 connetion to the PFE
>> These packets have a lower priority than other control traffic and 
>> will
>> be dropped when necessary. It is advisable to limit them as per the
>> document I posted:
>>
>>>>> http://www.juniper.net/solutions/literature/app_note/350013.pdf
>>
>> As this will guard against incoming DOS attacks.
>>
>> show pfe statistics ip icmp
>>
>> This shows all icmp packet statistics for the PFE.
>>
>> The pfe cpu complex limits icmp to 50pps per ifl and 500pps box wide
>>
>> I hope this clears up any confusion
>>
>> Gary
>>
>>
>