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Example: Configuring an MX Router as an SAEGW-U

This example shows how to configure an MX Series Router as an SAEGW-U for the Junos Multi-Access User Plane solution.


This example is also valid for configuring an MX Series Router as a UPF for 5G sessions. Junos Multi-Access User Plane can support 4G and 5G sessions simultaneously.


This example uses the following hardware and software components:

  • MX480 (can also be MX240, MX960) router with:

    • Two MPC7s to act as anchor packet forwarding engines (PFEs) to handle GTP-U processing

    • Two MPC2s (can also be MPC3, MPC5, MPC7, MPC10) to act as ingress and egress PFEs

  • Junos OS Release 21.3R1 or later

Figure 1 below shows the hardware for this example.

Figure 1: Standard setup for MX Series router as SAEGW-UStandard setup for MX Series router as SAEGW-U
  • The ingress line card (slot 0) provides the S1-U interface, connecting to the radio access network (RAN), and the combined Sxa/Sxb interface, connecting to the SAEGW-C.

  • The anchor PFE line cards (slots 1 and 2) provide the core processing of data traffic through internal pfe- interfaces. At least one anchor PFE card is required, but two are recommended to provide redundancy.

  • The egress line card (slot 3) provides the SGi interface, connecting to the core Internet.

Before you configure the MX Series Router as an SAEGW-U for the Junos Multi-Access User Plane solution, be sure you have:

  • At least one configured SAEGW-C that you provide

  • At lease one eNodeB

  • Access to a packet data network (PDN)



In this example (see Figure 2):

  • An MPC2 is in slot 0 with ge-0/0/0.1 providing the combined Sxa/Sxb interface and ge-0/0/0.2 providing the S1-U interface.

  • MPC7s are in slots 1 and 2 to provide the anchor PFE interfaces.

  • And MPC2 is in slot 3 with ge-3/0/0.1 and ge-3/0/0.2 providing SGi interfaces.

Figure 2: Configuring an MX Router as an SAEGW-UConfiguring an MX Router as an SAEGW-U


CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, and then copy and paste the commands into the CLI at the [edit] hierarchy level.


Step-by-Step Procedure

The following example requires you to navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode.

To configure the MX Router as an SAEGW-U:

  1. Enable DDoS attack protection for PFCP protocol traffic.

  2. Configure Graceful Restart (GRES).

  3. Configure slot 1 & slot 2 for anchor PFE processing.

  4. Enable enhanced IP network services.

  5. Configure the ingress logical interfaces using vlans.

  6. Configure the egress PFE for routing to core/ Internet for subscriber in VRF default (apn1).

  7. Configure the loopback address and the mobile interface for subscriber VRFs.

  8. Define the redundancy anchor PFE interfaces.

  9. Name the SAEGW-U gateway juniper-upf1 and configure the address where PFCP peers will connect to the SAEGW-U. Also, configure two APNs for SAEGW-U (apn-default to place sessions in the default routing instance and apn-vrf1 for sessions into VRF1).

  10. Configure the address where GTP-U peers will connect to the SAEGW-U.


    This is done at a different command hierarchy from the previous step.

  11. Configure aggregate interface apfe0 for PFCP processing.

  12. Configure the egress PFE for routing to core/ Internet for subscriber in VRF vrf1 (apn2).


From configuration mode, confirm your configuration by entering the show chassis, show interfaces, show services, show routing-instances, and show unified-edge commands. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.

If you are done configuring the device, enter commit from configuration mode.


Use various show commands to verify the SAEGW-U is functioning properly.

Verify SAEGW-U State


Verify the SAEGW-U is running and that GRES is enabled.


Verify SAEGW-U Peers


Verify the SAEGW-U has connected and is communicating with the SAEGW-Cs (control peers) and eNodeBs (access peers).


Verify SAEGW-U Sessions


Verify the SAEGW-U has active data sessions.


Release History Table
Starting in Junos OS Release 21.3R1, Junos Multi-Access User Plane provides a long-route implementation as a replacement for a filter-based implementation to steer traffic to the anchor Packet Forwarding Engine removing the need for a firewall filter to route GTP packets.