[c-nsp] Cisco Selective Packet Discard and ISR 3825 Routerrunning IOS 12.4 mainline

[hjan]

----- Original Message ----- 
From: "William Chu" <william_w_chu at hotmail.com>
To: <bep at whack.org>
Cc: <cisco-nsp at puck.nether.net>
Sent: Wednesday, October 11, 2006 1:45 AM
Subject: Re: [c-nsp] Cisco Selective Packet Discard and ISR 3825 
Routerrunning IOS 12.4 mainline


> Thanks, Bruce.
>
> Yes, I have read it before but I would like to know how SPD performs 
> random
> drops. This doc talks about dropping low priority packets, but exactly 
> what
> are low priority packets the document didn't really say it.  For example,
> does SPD look at ip precedence and perform drops like WRED?

SPQ use two queue : a general queue and a priority queue.
Packets put in the priority queue include routing protocol packets or those 
with ip precedence set to 6.
General queue is for holding packets from some other application that also 
need cpu's attention.
When queue size of the general queue is between a min and max threshold, 
packets are dropped randomly.

Regards,
Gianluca