Re: [Linux-vrf-general] Loopback address and scalability problems in VRF

[Yue L. <yu...@gm...>]

Hi, James,
Thanks for your advices.
I followed your suggestions, insert the dummy module, associate the dummy
intf to VRF 1, and assign 127.0.0.1/8 to it.

But when I ping 127.0.0.1 in VRF 1, I get no response.
There is a route in VRF 1 : "127.0.0.0/8 dev dummy0 proto kernel scope link
src 127.0.0.1 vrf 1"
but it seems that the dummy intf doesn't act as a loopback intf, so the XORP
processes can not communicate through it.

So I wonder whether I need to add some policy into iptables or change the
dummy module a little bit.


2007/11/29, James R. Leu <jl...@mi...>:
>
> You can create dummy interfaces and assign them to a VRF and then
> assign it the address 127.0.0.1/8.
>
> In /etc/modprobe.conf:
>
>     alias dummy1 dummy
>     install dummy1 insmod dummy -o dummy1
>
> Then:
>
>     ip link set dev dummy1 vrf 1 up
>     ip addr add 127.0.0.1/8 dev dummy1
>
> As far as increasing the number of VRFs, you could try to raise the
> VRF_MAX value, but I heard of issue with the kernel not booting if you
> make it too big.
>
> I am currently working on reimplementing the VRF patch on a 2.6.23 kernel
> which will have a limit of 2^31 - 1 number of VRFs (signed int)
>
> It still has a long way to go, so you should probably look at different
> ways to test your scalability.
>
> On Thu, Nov 29, 2007 at 07:27:04PM -0500, Yue Li wrote:
> > Hi, James and VRF users,
> > We are doing experiment of large scale routing protocol testing using
> VRF
> > and XORP. We want to
> > run multiple XORP instances on a single machine, each XORP instance
> resides
> > in one VRF. We use VRF because it is much more light weight than virtual
> > machines. The VRF version we are using is 0.900. Now we found two
> problems:
> > 1. As known, XORP adopts a multi-process architecture, the processes
> (belong
> > to one XORP instance) bind to different port numbers and communicate
> through
> > the loopback address 127.0.0.1. But it seems that there is no loopback
> > address in VRFs (other than 0). Because many network applications are
> using
> > this default loopback address I think this limitation may hinder a lot
> of
> > applications to run on top of VRF.
> >
> > 2. The current version has a scalability limit, so we can not create
> more
> > than 7 VRFs.
> >
> > So I wonder whether there is a new version or patch which can solve the
> two
> > problems above. I am grateful for any of your suggestions. Thanks.
> >
> > - Yue
>
> --
> James R. Leu
> jl...@mi...
>
>