[j-nsp] MX ping - ToS overrided

[Alex Arseniev]

You are monitoring ToS in ICMP ECHO REPLY, not request.
And that can be set/overridden anywhere by QoS policies, i.e.
- on Google DNS server 8.8.8.8 itself
- on any transit network
HTH
Thanks
Alex

On 22/01/2014 14:21, Arash Alizadeh wrote:
> Hi,
>   
> I'm experiencing issues when initating ToS ping from MX devices. The specified ToS argument just seems to be overrided to dec 192 when leaving the interface.
>   
> I verified this with the traffic monitor on the egress interface:
>   
> user at node> ping 8.8.8.8 tos 96
> 64 bytes from 8.8.8.8: icmp_seq=0 ttl=246 time=15.675 ms
> 64 bytes from 8.8.8.8: icmp_seq=1 ttl=246 time=15.385 ms
>   
> user at node> monitor traffic interface xe-0/0/0.0 extensive matching icmp
> PFE proto 2 (ipv4): (tos 0xc0, ttl 255, id 16332, offset 0, flags [none], proto: ICMP (1), length: 84) x.x.x.x > 8.8.8.8: ICMP echo reply, id 47826, seq 0, length 64
> 14:06:58.721197 Out
>   
> I've tried this on 11.4R6.6 and 12.3R4-S2 (ppc and 64-bit) boxes with the same result.
>   
> Did anyone else ran into this issue?
> Any input is appriciated.
>   
> Regards,
> Arash
>   		 	   		
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