JUNOS routed interfaces

Quick one today and a memory refresh for myself. Routed L3 links between a SRX and an EX2200-C. I have currently two up links connected between the two. I want to advertise a L3 VLAN across to the SRX. I want the interconnect to be two L3 point to point link. First lets create the routed point to point links. The SRX first.

set interfaces fe-0/0/4 unit 0 family inet address 172.16.1.1/30
set interfaces fe-0/0/5 unit 0 family inet address 172.16.1.5/30

Now time for the EX.

set interfaces ge-0/1/1 unit 0 family inet address 172.16.1.6/30
set interfaces ge-0/1/0 unit 0 family inet address 172.16.1.2/30

With the links up we will create a vlan with a layer three interface on the EX switch. Put an interface with an active interface into the VLAN.

set interfaces vlan unit 15 description "ENGINEERING L3 INT"
set interfaces vlan unit 15 family inet address 10.0.15.1/24

set vlans ENGINEERING description "Engineering Department"
set vlans ENGINEERING vlan-id 15
set vlans ENGINEERING l3-interface vlan.15

set interfaces ge-0/0/10 unit 0 family ethernet-switching vlan members ENGINEERING

Juniper doesn’t have the equivalent of the Cisco auto-state ignore feature. This removes the pre-requisite of an active port in the VLAN for SVI up status. Now, with my Advanced Features licence, I can run OSPF on my EX. The following commands will advertise the required interfaces into OSPF.

set protocols ospf area 0.0.0.0 interface ge-0/1/0.0
set protocols ospf area 0.0.0.0 interface ge-0/1/1.0
set protocols ospf area 0.0.0.0 interface vlan.15

Then put the following configuration onto the SRX to advertise the required networks to the EX.

set protocols ospf area 0.0.0.0 interface fe-0/0/4.0
set protocols ospf area 0.0.0.0 interface fe-0/0/5.0
set protocols ospf area 0.0.0.0 interface vlan.0
set protocols ospf area 0.0.0.0 interface vlan.20

Now let us check the OSPF status to confirm a relationship and a L3 routed interface.

[email protected]> show route 10.0.15 

inet.0: 13 destinations, 13 routes (13 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

10.0.15.0/24       *[OSPF/10] 00:01:28, metric 2
                      to 172.16.1.2 via fe-0/0/4.0
                    > to 172.16.1.6 via fe-0/0/5.0

[email protected]> show ospf interface 
Interface           State   Area            DR ID           BDR ID          Nbrs
fe-0/0/4.0          BDR     0.0.0.0         10.0.15.1       1.1.1.1            1
fe-0/0/5.0          BDR     0.0.0.0         10.0.15.1       1.1.1.1            1

Awesome. Note that you can access the 10.0.15.0/24 network via two routed interfaces. The > denotes that it is the selected route. You have achieved two cool things in this lab. A routed interface and advertised a VLAN Layer 3 interface.

Disclaimer

I do have a disclaimer about my blog and how I operate in the blogging world with integrity. I do declare here and with other posts that this Juniper Networks EX2200-12P switch was provided to me by Francois Prowse, on behalf of Juniper Networks. I was not asked for positive, marketed, vendor drivel. I will blog honestly about the platform and my experiences and share what I find, good or bad.

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