I thought a good way of refreshing my JunOS routing knowledge was to setup a fairly complex lab from scratch. Though I believe that sometimes, diagrams should be matched to a scenario – just to give it a sense of reality.

In the next few blogs, I’ll go through the entire process of joining three networks and achieving full connectivity between them from setting the network up, to getting the redistribution done.

I decided to split this process into additional blogs as below:

  1. The Lab scenario (this blog)
  2. Configuring the ISPs Network (Internet)
  3. Configuring Company A
  4. Configuring Company B
  5. Achieving Full Connectivity

I will also provide full JunOS configuration.

Just in case you want to replicate this topology and get the configuration done yourself…

  1. Virtual devices based on vMX (w/ trial license)
  2. The virtual machines are hosted on ESXi (vSphere v6.2); I’ve added maximum number of vNICs
  3. Download topology configuration – though keep in mind the following:
    1. no routing is configured
    2. only ip addresses are configured as well as iso addresses for loopbacks
    3. links connecting customer-A and customer-B are not configured at all (assuming the networks have not been joined yet)
    4. neither customer is yet connected to the Internet

Make sure you replace the string encrypted-password to plain-text-passwordfollowed by your own password.


The entire network topology comprises of two networks representing two different businesses, as well as the Internet cloud. Eventually, these two networks will be joined (Part 5) and full connectivity achieved throughout.

The process will indeed imply making design decisions and configuration changes.


Both companies connect to the Internet via the same ISP; the links have been highlighted in red.

Internet/ISP (AS 250) – see part 2 for more details

Provides Internet access to both companies. Furthermore, the following applies:

  1. Internal connectivity achieved via IS-IS
  2. It provides Company A and Company B with the ranges and respectively
  3. Internal ranges:
    1. Loopbacks:
    2. WAN Internet Links:
  4. Other ranges are known from upstream providers – each router injects a 200.100.x.0/24 range (x is the router number)

Company A (AS 10) – see part 3 for more details

  1. Network running RIP and multi area OSPF
  2. Internet access is achieved by means two links connected to the same ISP (AS 250):
    1. through the remote office (R-08 to R-11)
    2. through main office (R-09 to R-11)
    3. Local AS 10
  3. Internal ranges:
    1. Loopbacks:
    2. WAN Internet Links:

Company B – see part 4 for more details

  1. IS-IS network
  2. Internet access occurs over one single link between R-01 and R-12 using a static default route
  3. No AS# needed since this is (at this stage) a single homed network
  4. Internal ranges:
    1. Loopbacks:
    2. WAN Internet Links:

Thank you,
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