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Contributor
Posts: 90
Registered: ‎10-19-2013
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Accepted Solution

Bridge-domain,multiple vlans and flooding domains

[ Edited ]

 Hello everyone.

 

Please consider the following example:

 

MX4 R1:

 

EXAMPLE {
domain-type bridge;
interface x0-0/0/0.0  (  Trunk port carring vlans 4)
Interface x0-2/2/2.0  ( trunk port carrying vlan 5)
interface x0-1/1/1.0  ( access port in vlan 4)
vlan-id 4,5
 

 

 

Let say R1 receives a frame on xo-1/1/1.0 which is an access port in vlan 4,  with destination ffff.ffff.ffff

 

Will R1 flood that frame out of trunk port x0-2/2/2.0 too because vlan 5 is a part of same  bridge domain" EXAMPLE" ?

 

Thanks and have a nice day!!

 

 

 

 

 

Super Contributor
Posts: 102
Registered: ‎03-11-2012

Re: Bridge-domain,multiple vlans and flooding domains

Packets received on a trunk interface are forwarded within a bridge domain that has the same VLAN identifier

https://www.juniper.net/documentation/en_US/junos/topics/concept/layer-2-services-bridging-overview....

Distinguished Expert
Posts: 575
Registered: ‎08-15-2012

Re: Bridge-domain,multiple vlans and flooding domains

Hi,

 

I was wondering whether the config is a valid working one as I am not sure more than one vlan-id [vlan-id 4,5] can be configured under bridge-domains.

 

For multiple vlan-ids in bridge-domain, vlan-id-list needs to be configured. Example:

# show bridge-domains
test {
    vlan-id-list 4-5;
}

# show interfaces
ge-0/0/1 {
    unit 0 {
        family bridge {
            interface-mode access;
            vlan-id 4;
        }
    }
}
ge-0/0/2 {
    unit 0 {
        family bridge {
            interface-mode trunk;
            vlan-id-list [ 4 5 ];
        }
    }
}
ge-0/0/4 {
    unit 0 {
        family bridge {
            interface-mode trunk;
            vlan-id-list 5;
        }
    }
}

# run show bridge domain brief

Routing instance        Bridge domain            VLAN ID     Interfaces
default-switch          test-vlan-0004           4
                                                     ge-0/0/1.0
                                                     ge-0/0/2.0
default-switch          test-vlan-0005           5
                                                     ge-0/0/2.0
                                                     ge-0/0/4.0


BUM traffic from an access port gets flooded to member interfaces of that vlan only.

 

In the example, BUM from ge-0/0/1 [access vlan4] will be flooded to ge-0/0/2 [trunk vlan4,5] but not flooded to ge-0/0/5 [trunk vlan5].

 

Cheers,

Ashvin

Contributor
Posts: 90
Registered: ‎10-19-2013
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Re: Bridge-domain,multiple vlans and flooding domains

[ Edited ]

Hi Ashvin,

 

Thanks for your response, yes it was a typo, vlan-id list shuld be there.

 

I have some questions ( unfortuantely I do not have access to real gear so can not check myself):

 

This is I noticed in your config:

 

You defined single  bridge-domain " test" with vlan 4,5

 

 

But your command below shown separte bridge domains were created for each vlan even though you defined single bridge domain  " test":

 

So is it correct if I define single bridge domain X with two vlans 1,2 , we will end up with two bridge domains X-vlan 1, X vlan-2?

 

Apprecaited!!

 

 run show bridge domain brief

Routing instance        Bridge domain            VLAN ID     Interfaces
default-switch          test-vlan-0004           4
                                                     ge-0/0/1.0
                                                     ge-0/0/2.0
default-switch          test-vlan-0005           5
                                                     ge-0/0/2.0
                                                     ge-0/0/4.0

 

 

Highlighted
Distinguished Expert
Posts: 575
Registered: ‎08-15-2012

Re: Bridge-domain,multiple vlans and flooding domains

Hi, 

 

This is correct. I guess it is single vlan per bridge-domain, however still a under single virtual-switch instance [default-switch].

If I add another vlan to the list, another bridge-domain gets created:

root@Bridge# set bridge-domains test vlan-id-list 10 

[edit]
root@Bridge# show bridge-domains 
test {
    vlan-id-list [ 4-5 10 ];
}

[edit]
root@Bridge# commit and-quit 
commit complete
Exiting configuration mode

root@Bridge> show bridge domain brief 

Routing instance        Bridge domain            VLAN ID     Interfaces
default-switch          test-vlan-0004           4        
                                                     ge-0/0/1.0
                                                     ge-0/0/2.0
default-switch          test-vlan-0005           5        
                                                     ge-0/0/2.0
                                                     ge-0/0/4.0
default-switch          test-vlan-0010           10 

Cheers,

Ashvin

Contributor
Posts: 90
Registered: ‎10-19-2013
0 Kudos

Re: Bridge-domain,multiple vlans and flooding domains

Awesome!!

 

Thanks and have a great weekend!!!