Martin,
If I understand whay you are suggesting, there is a problem in your
design: It will only work if you use Hide NAT. The problem is that the
ip_src == IP0 rule is wrong: The ip_src is not changed by the router and
it is not equal to the IP of any of the machine interfaces.
Can you think of a solution that will work in the following reasonabl
scenario:
Lets say I have two T1 internet connections connected to one ethernet
interface. I do not use Hide-NAT.
I want to guarantee at least 512kbps to HTTP traffic on each line
(seperately) in the 'virtual circuit' method that you mentioned.
I see no way do do this unless I can attach a qdisc to a specific
virtual interface.
Aron
> Message: 3
> Date: Wed, 28 Jan 2004 00:54:39 -0600 (CST)
> From: "Martin A. Brown" <mabrown-lartc@xxxxxxxxxxxxxx>
> To: Gordan Bobic <lartc@xxxxxxxxxx>
> Cc: lartc@xxxxxxxxxxxxxxx
> Subject: Re: Shaping Device Aliases
>
> Gordan,
>
> I've noticed that you are trying to use aliased IP addresses and
> traffic control together, and you are a bit frustrated that tc doesn't
> handle aliased interface names.
>
> : > > I understand that device aliases (e.g. eth2:3) are not
shapeable.
> : > > Does anybody know if this functionality is planned in the
future?
> : >
> : > None of the new(er) networking tools recognise device aliases,
> : > because on all recent linux releases, aliases don't exist.
> : > the ethX:X notation is a legacy notation used only by the
> ifconfig
> : > program. everything else just sees a ethX with more than one IP
> : > address.
> : >
> : > So you just run your shaping rules on the real interfaces, and
> : > restrict it's operation with IP address filtering.
> :
> : Yes, I am aware of that. However, that makes shaping multiple
> : independent "streams" going through one interface much more
difficult.
>
> I don't understand why this becomes much more difficult--it just
> becomes a little more difficult, depending on the number of IP
> addresses you have active on a given interface. If you can handle
> multiple addresses on an interface, then shaping traffic on these
> (known) addresses shouldn't be much more difficult than managing each
address.
>
> : The only other thing I can think of is setting up a dummy network
> : device and giving it the IP addresses on all the non-primary
> subnets
> : (e.g. multiple DSL lines), and setting up the arp and routing to
> make
> : the packet actually go via the primary interface.
>
> This sounds like a very confused idea. I'm not sure it's worth the
> hassle--as I hope I can convince you below.
>
> [ more stuff snipped ]
>
> : Has anybody got any thoughts on this?
>
> I have some thoughts, which I hope can help you understand why you
> will be able to use the traffic control tools to accomplish your
> filtering. For posterity, I'll reiterate some of what has come
before.
>
> IP aliases don't exist. This is a convention for ifconfig. "ip addr
> show" will display all IP addresses active on a given interface.
>
> Traffic control is the last thing performed before turning the packet
> over to the device driver and hardware. Similarly, it is the first
> thing called on receipt of a packet. See diagrams KPTD [0] and
> ebtables packet flow [1].
>
> In this case, you can use any number of techniques to identify the
> packets with tc tools based on their IP addresses--the convenience of
> the aliased interface naming is simply an obstruction of the real path
> the packet takes.
>
> : If this would work, maybe it should be documented in the advanced
> : routing howto, as I can see how there might be a lot of people out
> : there who would find it useful.
>
> Let me suggest a possibility, if we assume a nested configuration.
> Let's say you have IP0 and IP1 active on interface eth3 and you want
> to make sure that bandwidth is split 75/25 between these two and you
> want them to share bandwidth. Classic bandwidth-sharing
> situation....in the tcng config below, you'd need to #define IP0 and
> IP1, but then you'd have a simple configuration. If you needed to
> further subdivide traffic within each of the IP0 and IP1 classes,
you'd have an easy way to do so.
>
> dev eth0 {
> egress {
> class ( <$ip0> ) if ip_src == IP0 ;
> class ( <$ip1> ) if ip_src == IP1 ;
> htb () {
> class ( rate 1544kbps, ceil 1544kbps ) { /* T1 speed
*/
> $ip0 = class ( rate 1024kbps, ceil 1544kbps ) ;
> $ip1 = class ( rate 384kbps, ceil 1544kbps ) ;
> }
> }
> }
> }
>
> Alternately, you may wish to simulate virtual circuits with each of
> the IP addresses on a machine. In this case, you could use separate
> root classes attached to the HTB qdisc, or another class. You can
> prevent the two classes from competing with each other by setting the
> rate and ceil to the same value. Here's a very simple permutation of
the above.
>
> dev eth0 {
> egress {
> class ( <$ip0> ) if ip_src == IP0 ;
> class ( <$ip1> ) if ip_src == IP1 ;
> htb () {
> class ( rate 1544kbps, ceil 1544kbps ) { /* T1 speed
*/
> $ip0 = class ( rate 1024kbps, ceil 1024kbps ) ;
> $ip1 = class ( rate 384kbps, ceil 384kbps ) ;
> }
> }
> }
> }
>
>
> Best of luck, Gordan!
>
> -Martin
>
> [0] http://www.docum.org/stef.coene/qos/kptd/
> [1] http://ebtables.sourceforge.net/br_fw_ia/PacketFlow.png
>
> --
> Martin A. Brown --- SecurePipe, Inc. --- mabrown@xxxxxxxxxxxxxx
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