Reth interface or redundant Ethernet interface is a special type of interface that has the characteristics of aggregated Ethernet interface. To configure Reth Interface in Junos (SRX), you have to first understand the basics of SRX HA basics. Reth interfaces are configured when SRX device is in HA (High Availability) mode. In JunOS there are two types of interfaces, redundant Ethernet interface (e.g. Reth1, Reth2) and local interface (e.g. ge-0/0/0, ge-0/0/1). The Reth interface is similar to ether channel or bundle where there is more and one member interfaces. Similarly, local interface is an interface that is independent on its own and is not a member of Reth interface. Here, I will show you how to configure Reth interfaces in a cluster environment.
Configure Reth Interface in Junos (SRX)
We will create Reth interfaces, based on above scenario. We will create two Reth interfaces, one for redundant internet link and on for internal network. The HA is already configured. This is Active/Passive HA where, Node 0 is active and Node 1 is passive. Now I will show you how to configure Reth interface in JunOS.
Before creating Reth interfaces, you have to set the number of Reth interfaces under [edit chassis cluster] hierarchy. This is similar to configuring Bundle where you have to specify number of bundle interfaces before actually assigning local interfaces to bundle interfaces.
Step 1
Define number of Reth Interface for the cluster.
{primary:node0} [edit chassis cluster] root@SRX240# set reth-count 2The above command will create 2 Reth interfaces. You can see the two Reth interface by issuing following commands.
{primary:node0} [edit chassis cluster] root@SRX240> show interfaces terse | match reth reth0 up upreth1 up up
Step 2
As we have already created 2 Reth interfaces. Now, let’s assign local interfaces to the Reth interfaces. To do so, hit the following command.
{Primary:node0} [edit interfaces] root@SRX240# set ge-0/0/2 gigether-options redundant-parent reth0 {Primary:node0} [edit interfaces] root@SRX240# set ge-5/0/2 gigether-options redundant-parent reth0 {Primary:node0} [edit interfaces] root@SRX240# set ge-0/0/4 gigether-options redundant-parent reth1 {Primary:node0} [edit interfaces] root@SRX240# set ge-5/0/4 gigether-options redundant-parent reth1Step 3
Now configure Redundant Group for the Reth interfaces.
{Primary:node0} [edit ] root@SRX240# set interfaces reth0 redundant-ether-options redundancy-group 1 {Primary:node0} [edit ] root@SRX240# set interfaces reth1 redundant-ether-options redundancy-group 1Step 4
You have successfully configured Reth interfaces. Now you can configure IP address or other configuration in Reth interfaces just like you do in local interfaces.
{Primary:node0} [edit ] root@SRX240# set interfaces reth0 unit0 family inet address 192.168.1.1/30 {Primary:node0} [edit ] root@SRX240# set interfaces reth1 unit0 family inet address 192.168.2.1/24In this way you can configure Reth interface in Juniper SRX HA mode. For more information about Reth interfaces visit Juniper.net.
