[Xorp-hackers] VLANs

[Kristian Larsson]

On Tue, May 09, 2006 at 12:58:20AM -0700, Pavlin Radoslavov wrote:
> > Vyatta have had working VLAN support for some
> > time                                                                                                                                                           
> > now. Is there anyone having any objections                                                                                                                                                                   
> > backporting this into XORP?                                                                                                                                                                                  
> > I know the support is only for Linux, but by                                                                                                                                                                 
> > starting with the Vyatta code we can work our
> > way                                                                                                                                                            
> > from there.                                                                                                                                                                                                  
>                                                                                                                                                                                                                
> In general, we would like to port-back (as time
> allows us) many of                                                                                                                                             
> the good things the Vyatta folks have added to
> their code.                                                                                                                                                     
>                                                                                                                                                                                                                
> However, in case of VLAN specifically, the
> Vyatta solution won't                                                                                                                                               
> work for us, because it is not portable. E.g.,
> the interfaces.tp                                                                                                                                               
> rtrmgr template file contains the following
> %create commands which                                                                                                                                             
> deal with creating VLAN vifs:                                                                                                                                                                                  
>                                                                                                                                                                                                                
>         %create:  program "modprobe 8021q";                                                                                                                                                                    
This makes sure the 802.1q module is loaded in the
kernel. I don't really think it is the job of XORP
to make sure the underlying operating system has
support for .1q, it is the responsibility of the
administrator. I for one would not use a module
but rather compile the support into the kernel.
>         %create:  program "vconfig add
>         $(ethernet.@) $(@)";                                                                                                                                                    
This is certainly not an elegant solution.
However there is no problem doing this from within
the fea. I've provided a very simple code example
of adding vlans on a Linux system, it's available
at
http://www.xorp.org/bugzilla/attachment.cgi?id=79&action=view

> Those external commands are Linux specific and
> we cannot use them in                                                                                                                                           
> XORP. Implementing it portably eventually means
> that we need to add                                                                                                                                            
> the appropriate support to the FEA, and this is
> not a trivial task.                                                                                                                                            
Yes I am aware of this. But I feel that we should
try to move in the "right" direction, whichever
direction that is.

And to be honest I don't really see the "non
trivial" parts of this as long as you're confident
with C it shouldn't be a problem, right ;)

   Kristian.