Transitioning to Mimosa Access

By David Stiff

Once the exclusive domain of cable and copper providers, the suburban, urban, and enterprise markets now represent an incredible opportunity for competitive broadband delivery via fixed wireless technology. With Mimosa’s introduction of the A5 access point and C5 client radio product lines, for the first time, fixed wireless technology has become significantly competitive with traditional wired modes of broadband delivery in increasingly high density environments.

Looking at the basic building blocks of Mimosa’s current network design architecture, and thanks to the very high 866 Mbps PHY rates on the C5 client radio, we designed it to act as a pure Layer 2 MAC bridge that coordinates directly with the A5 access point for advanced Layer 2 network isolation and VLAN functions. Subscriber Layer 3 termination, routing and NAT are recommended to be performed by an external subscriber router/gateway such as the Mimosa G2 Wi-Fi gateway or a 3rd party router.

In this respect, there are a number of software features Mimosa is developing for our ISP partners to integrate and automate critical subscriber management functions in the access ecosystem. Here is a glimpse into some of the features we plan to add over the next year to streamline the integration of a Mimosa Access solution into your existing network.

Using VLANs for Segmentation

VLANs are typically used to segment network traffic for security and network privacy reasons, providing discrete network segments used by routers for rate shaping, subscriber and billing management, and separating network management traffic out from subscriber internet data traffic. Mimosa’s current VLAN architecture supports VLAN per SSID, VLAN Pass-through, and Management VLANs. To make our system easier to integrate into customer networks that use a router or billing appliance to manage subscriber networks using 802.1Q VLAN tags, we are adding the ability to assign a unique VLAN per C5 client radio to allow per subscriber network segmentation.

PPPoE Transitioning

A widely implemented carryover from dialup and DSL days, Point-to-Point over Ethernet (PPPoE or RFC 2516) is a convenient approach that encapsulates PPP frames inside of Ethernet packets and tunnels them to an authentication and enforcement server. While popular for its ease in setting up subscriber accounts with simple rate limits, basic accounting, and Layer 3 termination, the technique also has its downsides which until now had limited impact to overall network performance and health.

First, the traffic encapsulation does add unnecessary overhead to each packet. More importantly though, encapsulation of subscriber traffic from the client all the way to the core of the ISP network leaves the remaining infrastructure of access points and backhaul radios blind to network trends other than basic QoS. This lack of visibility makes it difficult to manage heavy congestion or potential subscriber air, or traffic abuse impacting airtime health.

For this reason, Mimosa has added significant capabilities in the A5 access point to handle subscriber provisioning and enforce traffic management across all the clients connected to it. In this fashion, moving controls to the congestion point rather than the end client, you not only get basic rate limiting per client, but expanded traffic controls and air-time fairness management that offer far more sophisticated handling of air-time and traffic hogs.

Most PPPoE authentication servers utilize a radius server to authenticate and derive enforcement for bandwidth limits and VLAN controls. In addition to Mimosa’s current 802.1x/radius implementation for authentication, we are building support for vendor specific attributes (VSA) for subscriber policy enforcement, VLAN management and change of authorization (COA) using the radius protocol. These new features will allow service providers to automate the connection between subscriber management, network enforcement and redirecting new or unpaid customers to external remediation system. Customers requiring PPPoE support now can use Mimosa’s G2 Wi-Fi gateway as the PPPoE endpoint.

Managing Subscriber Routers

While many ISPs are now providing a managed home network solution to improve the in-home Wi-Fi experience, some ISPs prefer to allow subscribers to bring their own home router. Because these are unknown or untrusted devices, it can be challenging to properly assign a desired IP address to the subscriber, limit assigned IP addresses to a ‘paid for’ count, and protect the network against accidental or malicious DHCP IP starvation.

Taking a queue from technology used in larger metropolitan-area Ethernet deployments, often referred to as simply metro Ethernet, Mimosa is implementing the ability to insert Option 82 information into the DHCP request coming from the untrusted router at the subscribers site. This allows the DHCP server to make intelligent decisions on IP address assignment based on subscriber or network level information. For example, the number of IP addresses handed out per C5 client radio can be limited or an IP address can be locked to a specific router’s MAC address. If more than the specified number of devices are connected to a C5 client radio via a switch or a hub, they will not be able to connect, preventing DHCP IP starvation.

Provisioning Automation and Billing System Integration

New subscriber setup can be a time consuming task that slows down the ability to onboard new paying customers. Furthermore, if the setup requirements are complicated they require installation technicians with more advanced networking skills. To make installations simpler and more cookie-cutter like, Mimosa is working with billing system vendors and automation tools and templates to greatly simplify and speed up the time it takes to install a new customer. More to come on this one when we are ready to unveil it!

I hope you enjoy this insight into what Mimosa is working on under the covers. As always, our product teams at Mimosa really want to hear from you about ways to make our products integrate into your access ecosytems.

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