Congestion control/QoS

Sat May 24 03:31:52 UTC 1997

Dirk Harms-Merbitz <dirk at orlando.power.net> wrote:

>Seems to me that a good way of limiting damage from runaway
>networks/hosts would be a modifaction of RED (Random Early
>Drop).

>Controlled Early Drop (CED? I just made this up, suggestions?)
>would allow a router to give a preference to connected
>networks/hosts. Packets from certain networks would have a higher
>chance of being dropped from a router queue then packets from
>other networks.

This is a packet classification problem.

Here's a fragment from a test configuration file for my
boxes-as-being-developed:

-------------------------------------------------------------
ip-classifier FILTER1 {

	if( srcaddr = [192.40.77.20 : 192.40.77.90] and
	    ((proto = tcp and srcport <> [smtp, telnet, 512]) or
	     (proto = udp and dstport = domain)) ) {
		priority-select {
		0:      class PRIORITY
		1,2: {
			if( tos = bulk ) blackhole
			goto l1
		     }
		}
		reject
	}

	if( tos = [interactive, bulk, 017] ) class INTERACTIVE

l1:     if( dstaddr = 199.0.55.1 and tcp-syn ) reject

	class ROUTINE
}

ip-classifier DEFAULT {

	priority-select {
	    0:  class ROUTINE
	    1:  class PRIORITY
	}
	class INTERACTIVE
}

interface E1021-0 {
	description  "PL126612 to Joppa, MD"
	bandwidth    0.1G
	ip-address   144.227.0.11/24
	ip-secondary 199.0.88.11/24
	keepalive    no

	out-ip-classifier FILTER1

	out-class ROUTINE     { bandwidth 0.5% ; priority 4 }
	out-class PRIORITY    { bandwidth 20%  ; priority 5 }
	out-class INTERACTIVE { bandwidth 1M   ; priority 7 }

	ip-peer 144.227.0.12 {
		out-ip-classifier DEFAULT
	}

	ip-peer 144.227.0.50 {
		mac-address  01.29.00.11.91.21
	}
}

interface X123 {
	load-share [E1021-0, E1021-1, E777-0]
}
-------------------------------------------------------------

Are you netgeeks salivating yet? :)

--vadim