[Xorp-users] VLAN support in XORP

[Kristian Larsson]

On Wed, Sep 26, 2007 at 02:01:07AM -0700, Pavlin Radoslavov wrote:
> All,
> 
> The first-cut VLAN support is now committed in the CVS tree.
> 
> Below is some high-level information about the current configuration
> mechanism. Nothing is final so here is your chance to suggest
> improvements or alternative solutions.
> 
> Currently, the configuration looks like:
> 
> interfaces {
>     interface fxp0 {
>         vif vlan10 {
>             vlan {
>                 vlan-id: 10
>             }
>             address 10.10.10.10 {
>                 ...
>             }
>             ...
>         }
>     }
> }


What do the actual interface look like if I check
with `ifconfig` ?
Do I manually have to make sure that the "vif
vlan10" section doesn't collide with other
interfaces, ie do vlan 10 have to be unique and
will XORP or the user keep track of that?


> I.e., the "vlan {}" block inside the "vif {}" block is used to
> identify the vif as a VLAN and to apply the VLAN-specific
> configuration. For now the VLAN-specific configuration is only the
> VLAN ID.

Can't you put this thing under the main interface,
like adding "vlan-tagging" or something?
I don't want another two lines of configuration
per sub-interface.



> To add yet another possible solution, my personal preference and
> my original intention was to use configuration like the following:
> 
> interfaces {
>     interface fxp0 {
>         vlan vlan10 {
>             vlan-id: 10
>             address 10.10.10.10 {
>                 ...
>             }
>             ...
>         }
>     }
> }

I support this one.
Having an extra vlan { branch just adds more lines
and doesn't really bring anything useful, imho.


> In term of VLAN naming, the situation is the following.
> In FreeBSD (and I believe in other BSDs as well, but I haven't
> double-checked it yet), the vlan name has to be "vlan%d". However,
> the integer after "vlan" doesn't need to match the VLAN ID. E.g.,
> vlan10 could have VLAN ID of, say, 20.

I don't think so. I think you can rename the
interface to whatever you wish.


> In Linux the naming scheme can be programmed in advance using
> ioctl(SET_VLAN_NAME_TYPE_CMD). The choices are names like:
>  (a) vlan0005
>  (b) eth1.0005
>  (c) vlan5
>  (d) eth0.5
> 
> Unlike FreeBSD, in Linux the integer value at the end of the name
> must match the VLAN ID.

Are you sure?
I'm pretty sure you can rename the interfaces in
Linux as well. Let me get back on this.


> I believe (d) is the default naming scheme (where eth0 is the parent
> interface).
> However, for consistency with BSD and for naming clarity, currently
> the FEA explicitly selects (c) as the naming scheme. Therefore the
> sample configuration in the beginning of this email should work for
> both BSD and Linux (except that in Linux "fxp0" needs to be replaced
> with the parent interface name, say, "eth0").


  Kristian.

-- 
Kristian Larsson                                        KLL-RIPE
Network Engineer & Peering Coordinator      SpriteLink [AS39525]
+46 704 910401			              kll at spritelink.net