Tip

This is the documentation for the 25.06 version. Looking for the documentation of the latest version? Have a look here.

IS-IS over TEB GRE Interface¶

In this example R1 and R2 are connected with a GRE tunnel configured for Transparent Ethernet Bridging (TEB).

Note

This GRE tunnel could also be encapsulated inside a VPN (with a reduced MTU), however, this example uses an unencrypted connection to reduce the complexity of the example.

This example configures R1 first, followed by R2.

Note

This example assumes other configuration not mentioned is already present in TNSR as described in Required Information.

Configure R1¶

The first item to configure is the GRE instance between R1 and R2.

Define the instance with the source and destination as the WAN interface addresses on R1 and R2.

r1 tnsr(config)# gre toremote
r1 tnsr(config-gre)# instance 0
r1 tnsr(config-gre)# source 203.0.113.2
r1 tnsr(config-gre)# destination 203.0.113.30
r1 tnsr(config-gre)# exit

Enable and configure the GRE interface on R1 with a custom private MAC address and IP address:

r1 tnsr(config)# interface gre0
r1 tnsr(config-interface)# mac-address 66:f8:04:df:01:01
r1 tnsr(config-interface)# ip address 10.127.0.5/30
r1 tnsr(config-interface)# enable
r1 tnsr(config-interface)# exit

Warning

Each side must have a unique MAC address configured manually! TNSR will use the same default MAC address on each GRE interface by default, which causes a conflict.

Now define and configure the IS-IS server using the NET for R1 which is formed by combining the AFI, Area ID, System ID, and NSEL:

r1 tnsr(config)# route dynamic isis
r1 tnsr(config-frr-isis)# server vrf default
r1 tnsr(config-isis)# area-tag exco
r1 tnsr(config-isis)# net 49.0001.0100.0200.0001.00
r1 tnsr(config-isis)# is-type level-1
r1 tnsr(config-isis)# exit

Configure the GRE interface connected to R2 for IS-IS with the same ID as the server and enable IPv4. This interface must be configured as a point-to-point interface and hello padding must be disabled.

r1 tnsr(config-frr-isis)# interface gre0
r1 tnsr(config-isis-if)# area-tag exco
r1 tnsr(config-isis-if)# ipv4
r1 tnsr(config-isis-if)# point-to-point
r1 tnsr(config-isis-if)# hello padding disabled
r1 tnsr(config-isis-if)# exit

Configure the LAN interface for IS-IS with the same ID as the server and for IPv4, but mark the LAN as passive as there are no routers connected to the LAN:

r1 tnsr(config-frr-isis)# interface LAN
r1 tnsr(config-isis-if)# area-tag exco
r1 tnsr(config-isis-if)# passive
r1 tnsr(config-isis-if)# ipv4
r1 tnsr(config-isis-if)# exit

Lastly, enable IS-IS and exit:

r1 tnsr(config-frr-isis)# enable
r1 tnsr(config-frr-isis)# exit

Configure R2¶

The first item to configure is the GRE instance between R2 and R1.

Define the instance with the source and destination as the WAN interface addresses on R2 and R1.

r2 tnsr(config)# gre tohq
r2 tnsr(config-gre)# instance 0
r2 tnsr(config-gre)# source 203.0.113.30
r2 tnsr(config-gre)# destination 203.0.113.2
r2 tnsr(config-gre)# exit

Enable and configure the GRE interface on R2 with a custom private MAC address and IP address:

r2 tnsr(config)# interface gre0
r2 tnsr(config-interface)# 66:f8:04:df:02:02
r2 tnsr(config-interface)# 10.127.0.6/30
r2 tnsr(config-interface)# enable
r2 tnsr(config-interface)# exit

Warning

Each side must have a unique MAC address configured manually! TNSR will use the same default MAC address on each GRE interface by default, which causes a conflict.

Now define and configure the IS-IS server using the NET for R2 which is formed by combining the AFI, Area ID, System ID, and NSEL:

r2 tnsr(config)# route dynamic isis
r2 tnsr(config-frr-isis)# server vrf default
r2 tnsr(config-isis)# area-tag exco
r2 tnsr(config-isis)# net 49.0001.0100.3000.0001.00
r2 tnsr(config-isis)# is-type level-1
r2 tnsr(config-isis)# exit

Configure the GRE interface connected to R1 for IS-IS with the same ID as the server and enable IPv4. This interface must be configured as a point-to-point interface and hello padding must be disabled.

r2 tnsr(config-frr-isis)# interface gre0
r2 tnsr(config-isis-if)# area-tag exco
r2 tnsr(config-isis-if)# ipv4
r2 tnsr(config-isis-if)# point-to-point
r2 tnsr(config-isis-if)# hello padding disabled
r2 tnsr(config-isis-if)# exit

Configure the LAN interface for IS-IS with the same ID as the server and for IPv4, but mark the LAN as passive as there are no routers connected to the LAN:

r2 tnsr(config-frr-isis)# interface LAN
r2 tnsr(config-isis-if)# area-tag exco
r2 tnsr(config-isis-if)# passive
r2 tnsr(config-isis-if)# ipv4
r2 tnsr(config-isis-if)# exit

Lastly, enable IS-IS and exit:

r2 tnsr(config-frr-isis)# enable
r2 tnsr(config-frr-isis)# exit

Next Steps¶

The configuration is now complete. Proceed to Finish Up for information on testing.