Technology

Proxim’s Wireless
Outdoor Router Protocol

WORP is a protocol designed by Proxim to optimize the performance of outdoor wireless point-to-point and point-to-multipoint links.

  • WORP® utilizes a star architecture and a token-passing access methodology. Base stations dynamically manage all client access and bandwidth requirements.
  • WORP® maximizes the performance of multi-stream voice, video, and data over wireless networks.
  • WORP® provides the foundation for the exceptional efficiency and security inherent in every Proxim Point-to-Point and Point-to-Multipoint system.

Efficiency

WORP® is a dynamic, asynchronous protocol designed to optimize bandwidth usage. WORP’s asynchronous nature allows the uplink and downlink to adapt to network traffic demands dynamically.

In a WORP®-powered network, each base station independently manages on-demand bandwidth allocation and QoS configurations according to the needs of each client in the network. This approach dramatically increases overall network throughput compared to synchronized radio network systems.

By contrast, synchronized radio network systems use a fixed uplink/downlink ratio that must be common to all base stations in the network. In this case, a network configured to deliver 25% upstream and 75% downstream bandwidth cannot adapt to the dynamic bandwidth needs of the client. For example, a client needing mostly uplink traffic can only access 25% of the resource, and most of the remaining 75% is wasted because it is not available for upstream transmission.

WORP is typically >25% more efficient than synchronized systems.

Scalability

Proxim WORP® overcomes the limitations of many point-to-multipoint solutions based on the WiFi 802.11 MAC protocol. In 802.11-based systems, dense multi-node deployments suffer from packet collisions and subsequent re-transmission, dragging down network performance. Even in systems with as few as two or three remote nodes, network performance can be affected by excess packet collisions.

As a genuinely scalable system, Proxim WORP® adapts to higher traffic loads and number of subscribers while ensuring the total aggregate data available remains constant. In a WORP® enabled network, the deterministic management of network access ensures bandwidth is not wasted on overhead and that each Subscriber Unit (SU) can take advantage of the total network bandwidth for reception and transmission.

For example, A 100Mbps 802.11-based network with only five Clients has an expected aggregate data rate near 50Mbps. The same network with 50 Clients would degrade to around 25Mbps due to the CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) access protocol.

Given the same 100 Mbps network, Proxim WORP® would maintain a total bandwidth of 75 Mbps.

Security

Proxim WORP® offers multiple layers of security to protect valuable and private data during transmission.

The proprietary encapsulation protocol in WORP® ensures that any device used to capture data must first be able to decode WORP®. Other security measures ensure against using a WORP® enabled device for decoding.

  • WORP® requires a Subscriber unit (SU) to register with the Base Station unit (BSU), using an MD-5 secret string in the authentication process. Without the appropriate MD-5 key, rogue Subscriber Units cannot join the network.
  • WORP® implements up to 256-bit AES encryption on all over-the-air data transmissions.
  • All remote management methods use secure password-protected or certificate-based SSH, SSL/TLS, and SNMP v3 connections for remote management and access.
  • WORP can be configured to limit the maximum number of clients that can associate with each BSU. When that number is reached, the BSU will stop announcing itself. This limits the opportunity for a rogue client to attempt to join a BSU sector.

Quality-of-Service (QoS)

Just one of the many reasons why WORP® is better than WiFi for MultiPoint and backhaul networks.

Proxim WORP® enables sophisticated QoS management for efficient use of network bandwidth. WORP®’s QoS offers minimum and maximum data rates with programmable jitter and latency limits. It is configurable to operate within defined parameters for packet loss and data error rates.

Proxim WORP® based QoS includes three primary components:

  • Deep Packet Inspection (DPI) and the application of Packet Identification Rules (PIRs) provide precise classification of traffic
  • Service Flow Classes (SFC) to assign priority, bandwidth, latency, and jitter classification rules for different traffic types
  • Quality-of-Service Classes (QoSCs) to define which SFC or PIR is employed for each traffic class. A per-subscriber allocation

WiFi Hidden Node Problem

Another reason why WORP® is better than WiFi for MultiPoint and backhaul networks.

WiFi was explicitly intended for short-range indoor applications – the assumption that all clients can “hear” each other is evident in the WiFi MAC protocol. WiFi operates on a Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) access methodology, where each client de-vice listens to the network and if it does not hear another device communicating, assumes the channel is clear to begin transmission.

The assumption that all Subscriber units can hear each other is not valid for outdoor networks. Often, a Subscriber unit with a directional antenna obscured by buildings or trees will not “hear” the other subscriber units. As a result, multiple Subscriber Units would attempt to access the wireless medium simultaneously. This results in many re-transmissions which has a massive impact on network performance.

The Proxim WORP® protocol avoids the re-transmission problem by using the Base Station as an access control manager. A Subscriber unit cannot transmit data unless the BSU permits it, resulting in no collisions and no re-transmissions.