Re: Cisco ASR9902 SNMP polling ... is interesting

[Mel Beckman via NANOG <nanog () lists nanog org>]

Thanks for that informative — and civil — explanation. In my experience, packets can “drop out“ of ASIC processing 
under unexpected and unusual circumstances, resulting in high CPU loads. Hopefully escalation of the case works, and 
TAC discovers yet another bug that can be addressed in a firmware update.

-mel via cell

On Aug 2, 2025, at 9:35 PM, Ryan Hamel <ryan () rkhtech org> wrote:


Mel,

The control plane receives 100% of the packets, providing the control plane policies allow it to. The control plane is 
likely connected to the ASIC via a mix of a PCI-E interface (providing the programming interface and an emulated NIC) 
and/or a specialized NIC port. If the CPU port is experiencing packet loss (my stance is very unlikely), that can be a 
separate discussion. I agree that an escalation is the appropriate response here, where TAC should try to reproduce the 
issue with Drew's config.

Kind regards,

Ryan Hamel

________________________________
From: Mel Beckman via NANOG <nanog () lists nanog org>
Sent: Saturday, August 2, 2025 4:23 PM
To: Tom Beecher <beecher () beecher cc>
Cc: nanog () lists nanog org <nanog () lists nanog org>; Mel Beckman <mel () beckman org>
Subject: Re: Cisco ASR9902 SNMP polling ... is interesting

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I’ll just let the incivility of you both stand.

-mel

On Aug 2, 2025, at 3:52 PM, Tom Beecher <beecher () beecher cc> wrote:


Mel-

Saku did not call *you* any names. He called your *incorrect statements* in this thread 'bizzard drivel'. Which he is 
absolutely correct about. While your intentions may certainly have been to help, your statements here have been frankly 
dead wrong and did not accomplish that.

Probably just want to take the L here.


On Sat, Aug 2, 2025 at 5:34 PM Mel Beckman via NANOG <nanog () lists nanog org<mailto:nanog () lists nanog org>> wrote:
Saku,

What is actually appalling is that a member of NANOG calls “bizarre drivel” the honest and sincere attempts by other 
members to help identify the possible problem. There’s no cause to be uncivil, people can disagree without stooping to 
name-calling.

 -mel

> On Aug 2, 2025, at 11:46 AM, Saku Ytti via NANOG <nanog () lists nanog org<mailto:nanog () lists nanog org>> wrote:
>
> On Sat, 2 Aug 2025 at 21:02, Tom Beecher via NANOG
> <nanog () lists nanog org<mailto:nanog () lists nanog org>> wrote:
>
> > I don't have in depth knowledge of Cisco's SNMP implementations, or even
> > the ASR platform specifically, but if Cisco TAC is telling you this is
> > 'normal', they are completely full of shit, and you should click any and
> > every 'escalate' button you can find.
> >
> > This almost sounds like a default control plane DDOS policer / LPTS ,
> > something like that.
>
> There are various complicated reasons for this, LPTS policer is
> unlikely culprit, but possible. Bug search will show various DDTS with
> poor SNMP performance outcome, most of them are unrelated to LPTS.
>
> But absolutely correct, the right solution is to escalate. In common
> case this would be SE from your account team, who would fight for you
> internally.
>
>
> It is appalling that OP came to nanog after correctly suspecting TAC
> is gaslighting them, some community member piled on with what can only
> be described as a bizarre drivel.
> --
>  ++ytti
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