Wi-Fi Access Gateways

Wi-Fi access gateway (WAG) provides the public with Wi-Fi access from a residential Wi-Fi network or from a business Wi-Fi network. At home, subscribers have their existing Wi-Fi network; however, a part of their network is available for the general public to use. Members of the public who have an account with the same Internet service provider as the subscriber has at home can access the Internet and mobile network through the public part of the subscriber’s Wi-Fi connection when they are in close proximity to the subscriber’s home. WAG authenticates and connects subscribers regardless of their physical location.

Starting in Junos OS Release 17.2R1, service providers can deploy the MX Series router as a broadband network gateway (BNG) within their network, and then deploy the BNG as a WAG. Figure 1 shows a sample topology.

Figure 1: MX Series Router Deployed as a WAG

After a WAG has been deployed, service providers can configure the WAG to create secure wireless home network connections for computers, laptops, and other Wi-Fi electronic products (such as game systems, tablets, or mobile phones). WAG offers wireline and mobile service providers the following deployments and business value opportunities:

• Wireline service providers–The WAG deployment is based on an in-home division of access points or public access points, and works with any Wi-Fi access point that creates a generic routing encapsulation (GRE) tunnel to the MX Series router. This deployment protects subscribers and reduces churn by including free Wi-Fi with a paid wireline subscription. For added value, service providers can also sell ad hoc access or mode, such as airport, public safety, search-and-rescue, and café access.

• Mobile service providers–The WAG deployment is based on the mobile service provider’s own access points, or wholesale and retail with the wireline service provider. Service providers that offer quadruple play, where TV, Internet, wireless, and landline phone services are combined, can leverage both wireline and wireless assets. This deployment offsets costs in mobile packet core and radio access network infrastructures with the ability to offload mobile data. For added value, service providers can offer Wi-Fi for all devices with a mobile data place as a competitive differentiator.

Customers who purchase broadband can also receive Wi-Fi on any community Wi-Fi access point. Subscribers have a private and secure home connection, and can also access a public connection that is shared by other subscribers. To maintain a level of security and protect the private home connection, the two networks are separated. This separation ensures a strong level of bandwidth on the subscribers’ personal connections.

Subscriber services such as authentication, authorization, and accounting (AAA); address assignment; hierarchical quality of service (QoS); lawful intercept; and class of service (CoS) are supported for individual Dynamic Host Configuration Protocol (DHCP) subscribers within the GRE tunnels. Using GRE tunnels for Wi-Fi provides the following benefits:

• Wi-Fi users who are not directly connected through Layer 2 to WAG are authenticated because GRE tunnels transmit Layer 2 information across any IP network.

• Services based on user equipment-specific information are applied using the media access control (MAC) address or Subscriber Identity Module (SIM) card.

• Services are applied in the network, not just at the Wi-Fi access point.

• The soft GRE or Ethernet-over-GRE standard is supported on most Wi-Fi access points. For services using the Ethernet over GRE standard, only one side of the tunnel needs to be configured; the other end learns the remote IP addresses of all remote tunnel endpoints by examining the incoming GRE packets.

• The soft GRE feature enhances network scalability by enabling seamless integration of WAGs and supporting Layer 3 termination for UE.

• Anchoring on RLT improves fault tolerance and service availability, ensuring continuous connectivity even in the event of a failure. Active-active mode supports expanded processing bandwidth.

• Streamlines subscriber management and service delivery on network service models including PPPoE dual stack models that simplifies configuration and operational procedures.

• Facilitates efficient handling of both VLAN-tagged and untagged Ethernet frames, providing greater flexibility in network design and deployment scenarios.

• Supports high availability and redundancy in Wi-Fi offload scenarios, allowing for reliable network performance under various operational conditions.

Figure 2: MX Series as Wi-Fi Access Gateway Deployment Model

To support the MX Series BNG deployed as a WAG, dynamic-bridged generic routing encapsulation (GRE) tunnels are created and terminated at the BNG when it receives GRE traffic from the wireless access point (WAP). Dynamic Host Configuration Protocol (DHCP) or PPPoE subscribers are transported through GRE tunnels as either VLAN-tagged per service set identifier (SSID) or untagged. When the user equipment device connects to the SSID and begins to send traffic, the access point initiates a Layer 2 soft GRE or Ethernet-over-GRE connection to the MX Series BNG and the BNG dynamically builds the GRE tunnel. The softGRE tunnel configuration of source IP address, destination IP network, and associated PS interface is used to enable dynamic GRE tunnel creation service. The PS interface is anchored over logical tunnel interfaces. GRE tunnels are cleared after all of the subscribers within a GRE tunnel have logged out and a configurable timer has expired. Fault tolerance and service availability is supported through the use of Layer 2 softGRE tunnel anchored on redundant GRE tunnels, ensuring continuous connectivity even in the event of a failure.

This deployment model supports a full set of services per user equipment device and per access point. Subscriber services such as authentication, authorization, and accounting (AAA); address assignment; hierarchical quality of service (QoS); lawful intercept; and class of service (CoS) are supported for individual DHCP subscribers within the GRE tunnels. No additional service cards are required for GRE or QoS because all features run inline on MPCs.

External RADIUS proxy supports Extensible Authentication Protocol (EAP) Subscriber Identity Module (SIM), Tunneled Transport Layer Security (TTLS), and Authentication and Key Agreement (AKA) protocols. The External RADIUS proxy also integrates with HTTP redirect to the Web portal.

The MX Series as WAG deployment model also supports the wholesale of access point access to multiple retail service providers. This wholesaling allows the local breakout of traffic or Layer 3 handoff to retail service providers.

DHCP and PPPoE subscriber access modules are supported for packets carried over dynamic-bridged generic routing encapsulation (GRE) tunnels. Dynamic-bridged generic routing encapsulation (GRE) tunnels and the Wi-Fi access gateway support interface stacks for VLAN-tagged and untagged subscribers. Subscriber features such as authentication, address assignment, Class of service (CoS), dynamic and service profiles for DHCP subscribers, lawful intercept, firewall filters, and change of authorization (CoA) are supported.

Scaling limitations of pseudowire subscriber interface devices (psn IFDs) require that multiple tunnels share the same PS n IFD. The pseudowire is a virtual device that is stacked above the logical tunnel anchor point on the physical interface (the IFD).

The PS n IFD used to service dynamic GRE tunnel terminations cannot be simultaneously used to service MPLS pseudowire terminations. Subscriber services and lawful intercept are supported only at the IP demultiplexing (demux) interface level.

The tagged model and the untagged model are described in the following sections:

• Dynamic VLAN-Tagged Subscribers
• Untagged Subscribers