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

[James R. L. <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 resid=
es
> 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 problem=
s:
> 1. As known, XORP adopts a multi-process architecture, the processes (bel=
ong
> to one XORP instance) bind to different port numbers and communicate thro=
ugh
> 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 usi=
ng
> this default loopback address I think this limitation may hinder a lot of
> applications to run on top of VRF.
>=20
> 2. The current version has a scalability limit, so we can not create more
> than 7 VRFs.
>=20
> So I wonder whether there is a new version or patch which can solve the t=
wo
> problems above. I am grateful for any of your suggestions. Thanks.
>=20
> - Yue

--=20
James R. Leu
jl...@mi...