Switching

Hi ,

Not sure what is IRB ? what is it for ? could anyone tell me the concept of IRB, its configuration and some command to monitor ?

IRB is a logical Layer 3 interface - much like the vlan.x interface used in EX switches.  It is used a lot on the MX-series, and on the SRX-series in transparent mode.

It is configured just like an interface would be:

set interfaces irb unit 10 family inet address 10.0.0.1/24

Hope this helps

thanks, but what is it for ? what goal to accomplish with IRB ?

Hello Sam

As per my understading IRB interface is mostly required in bridged networks.

A bridge domain is a collection of tagged and untagged ports.So to route traffic out of the bridge domain and communicate between bridge domains you need the IRB interface.Check the example below

                                                   |nternet Cloud

                                                               |

                                                               |

DSLAM(Multiple Vlans)<---->MX Router(IRB)------->BRAS

This exmple is classic scenario where the IRB can be utilized.The traffic between the DSLAM and BRAS is bridged

and to route this traffic towards the internet you need IRB .

To further understand the bridge you better read about the classic fallback bridging scenario.

You may also like to check the BVI interface as reffered to by Cisco and is equivalent to IRB interface.

A good explanation for BVI is as follows

http://serverfault.com/questions/254347/what-is-a-cisco-bvi-interface-what-is-it-used-for

Note:This all is as per my understanding.If you and some one else finds something else then please do correct it.

Thanks & Regards

Malik

thanks, now i've some concept and trying to find some configuration as example ...

Hello Sam

Since, i did not find some good IRB example in Juniper.

I manged to see this great article which should clear the concept. It includes an example as well.

http://www.cisco.com/en/US/tech/tk389/tk815/technologies_tech_note09186a0080094663.shtml

Also, there is some slight differnce between IRB and BVI.I am sorry for explaining both the same.

Overall, dont forget to mark this as "Accepted Solution" ;-).

Regards

Malik

thank so much, Malik !