RE: UDP packet handling weird behaviour of various operating systems

[Boyan Krosnov <bkrosnov () yahoo com>]

> From: Stefan
Laudat[mailto:stefan () mail allianztiriac ro]
> 7. Cisco IOS
>       - tested on Cisco 7513 (12.1(4)E, DCEF enabled),
Cisco 
> 2621 (12.2.1),
> Cisco Catalyst 35xxXL (12.0.5.2.XU and 12.0.5.1.XP).
I'm 
> walking here on Linux-behaviour
> land. The CPU is burning at high load averages from
the start 
> and I get no control
> over it. I can get the result either directly
attacking the 
> router, either forwarding 
> for a host behind it. IOS plays the brave guy and
gets it for 
> anyone else too.

A single 100Mbps half duplex ethernet link may reach
as much as 150000 pps with tiny datagrams, 
which is far beyond 2621's forwarding perfomance and
comparable to 7513's with VIP4-80, RSP8.
Not to mention packets addressed to the routers, which
will probably get handled by the RSP IOS on 75xx.
This may be the reason for those routers dying.

Of course, opinions expressed are my own and not of my
company, nor Cisco Systems. I can easily be wrong on
this. I'm just reading the docs.

BR,
---
CCNP Boyan Krosnov
Networking Consultant
Lirex BG Ltd.


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