I'd like to see a worked example of recreating a regular common VLAN based topology using MPLS on Juniper hardware. In particular we will be using EX3xxx and EX4xxx for swicthing, though I don't think that's relevant. The router in question could be a Juniper MX.

Let's assume you have an existing network topology as follows:

               +--------------------+     Trunk     +---------+
               |      Switch 5      +---------------+ Router1 |
               |                    |               +---------+
               +--+-----------------+     VLAN2     +---------+
               |      Switch 1      +---------------+  Host5  |
               |                    |               +---------+
                  |              |                
                  |Trunk         |Trunk             
                  |              |                  
 +----------------+---+      +---+----------------+
 |      Switch 2      |      |      Switch 3      |
 |                    |      |                    |
 +---+------------+---+      +---+------------+---+
     |            |              |            |
     |VLAN2       |VLAN2         |VLAN3       |VLAN4
     |            |              |            |
+----+----+  +----+----+    +----+----+  +----+----+
|  Host1  |  |  Host2  |    |  Host3  |  |  Host4  |
+---------+  +---------+    +---------+  +---------+

All Trunk links allow all VLANs, and the router has sub interfaces in each VLAN.

  • 3
    Could you say something about what you're trying to accomplish with the change? Why do you want to deploy MPLS? In the meantime you may want to look at Juniper's This Week: Deploying MPLS book, which is free on their website. link – Craig Sirkin May 9 '13 at 13:55
  • Excellent suggestion thanks. The reason for this is more a simply proof of concept. – SimonJGreen May 9 '13 at 15:32
  • example of recreating a regular common VLAN based topology using MPLS - MPLS and VLANs are two different technologies. Do you mean you want to see an example of this using VLANs with VPLS for example, or PWE3 carried VLANs etc? You need to be more specific. – jwbensley Aug 7 '13 at 10:56

This looks like a simple layer two domain. MPLS is typically used only as backbone or distribution transit, that is, among routers. To implement MPLS, you would need to push the VLAN interfaces down to the access switches (and thus split Host5 into a new network or move it to switch 2) and run MPLS among the multilayer switches. Although, this wouldn't bring much benefit to the topology shown.


One use case of deploying MPLS would be to then deploy VPLS on top of this to emulate a regular L2 network. MPLS/VPLS will bring certain benefits like load sharing over multiple backbone routers (whereas L2 would just pick one best path) or that you could deploy other MPLS based features in parallel to your VPLS cloud.

Some Internet exchanges has moved to VPLS fairly recently, one being AMS-IX who have also posted some information on their setup; https://www.ams-ix.net/technical/ams-ix-infrastructure/the-ams-ix-mplsvpls-infrastructure

You can't build VPLS directly from your EX[34]xx boxes. EX4550 possibly does VPLS but I'm a tad uncertain. If you are running MX core you can do CCC (like EoMPLS but Juniper proprietary and only using one label) from the ports on the EX to the MX and switch it in the MX. I'm not sure what gain you would have from that though. If you only have one or two routers though, I don't see how this L2 topology will gain anything by the addition of baconMPLS/VPLS.

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