Switching

Hello , people as title says:

I m currently receiving tagged traffic over a trunk interface as shown in picture:

This lan segment is tagged with vlan4 and using my irb.4 interface as gw.

Now I need to receive other vlan segment but this time tagged with vlan5 and re-use the existing irb.4 gw

Is that possible ?

How can I declare vlan 4 , vlan5 and irb.4 on the same bridge-domain?

When I tryed to add the statement "vlan-id 5" it replaces the "vlan-id 4" previously setted.

Sumarizing:

My goal is to reach same irb.4 gw (172.26.1.254) from two different incomming vlans.

thanks.

Leandro.

Why?  What is your real reason or requirment.  If using the same GW then this is the same subnet, which therefore [generally] means the same VLAN.  No idea what the real requirment need is, which might be solved some other way, like private VLAN maybe?

Yes, this is possible, but you need to configure your interface in MX-style, not EX-style, and it's called VLAN normalization:

interfaces {
    ge-0/0/0 {
        flexible-vlan-tagging;
        encapsulation flexible-ethernet-services;
        unit 4 {
            vlan-id 4;
        }
        unit 5 {
            vlan-id 5;
        }
    }
}
bridge-domains {
    normalize-vlans {
        domain-type bridge;
        vlan-id 4;
        interface ge-0/0/0.4;
        interface ge-0/0/0.5;
        routing-interface irb.4;
    }
}

This is what we do for a connection to a transport provider that feeds us ADSL users over separate VLANs, but we want them to all be bridged onto the same broadcast domain (bridge-domain).  I haven't tested out the above configuration and if for some reason you cannot use vlan-id 4 on the bridge-domain if it's already in use on the interface, just change your vlan-id on the bridge domain to something that's not in use already.

It is an interesting idea;

Did you tested it ? Im currently  testing some work-around for it.

It will come to yo if I can test your lines.

Thanks!

LEo.

Let me be clear - the part I did not "test" was the assignment of the bridge-domain VLAN as 'vlan-id 4' with a logical unit that has the same vlan-id.  This is why I said if it does not work, just configure an unused vlan-id on the bridge-domain.  The concept as a whole does work - we use it in production for bridged ADSL customers who are transported across a provider's network and connect to us on separate VLANs.  All the ADSL users share a common broadcast domain and subsequently, a common IP subnet.

Hello , evt: What do you mean with "MX-style, not EX-style" , how do I change it ?

Regards,

Leandro.

I believe the real terms that Juniper has used in the past are 'Enterprise style' and 'Service Provider style'.  'EX-style', or 'Enterprise style', means that trunk configuration is done the way you currently have it - a port is configured as 'interface-mode trunk' and 'vlan members' are configured on it. 

'MX-style', or 'Service Provider style' is configured the way I've specified - each VLAN is configured on its own separate logical-unit.

There are just more options available for VLAN manipulation when using SP-style, as well as other functionality that you don't get when using Enterprise configuration style.

It is the question I was waitting for.
The problem is that I facing a Cheenese non administrable (for me) switch that is already configured. I can not change that it sends tagged frames over a trunking interface.
Thanks for your help.

Leandro.