Network Admin Using Linux

Network Admin Using Linux

Introduction

Wireless router platforms based on Linux are becoming more and more popular in the consumers' home networks. Although Linux is not a real-time operating system, it allows to develop cheap network devices with sufficient performance for most home network scenarios. Additionally, using a Linux platform allows manufacturers to offer a rich set of functionality and services that are developed and maintained by the community. Consequently, the platforms can also be used for multimedia services which include the possibility of using such platforms as media-aware network elements (MANE) for in-network adaptation or acting as network attached storage (NAS) to share multimedia content via SMB or UPnP. Evaluations with more recent platforms showed that their performance is sufficient to adapt even multiple high-definition streams. Most of these services have in common that they are typically implemented on the application layer and run as processes in the user space. This imposes higher requirements on the wireless router platforms which were initially developed and designed for typical networking tasks like routing and bridging.

Network Admin Using Linux

Hardware Platforms

All evaluated router platforms are intended for residential and small office-home office (SOHO) markets and can be considered as representative for millions of legacy devices that are nowadays deployed in home networks. The platforms were selected in a way that both their nominal CPU speed as well as their network connectivity covers a broad range of available devices. All have in common that they ship with firmware that is not a dedicated router or real-time operating system but based on a Linux kernel. The most relevant technical specifications of the evaluated router platforms are given in Table 1.

The LinksysWRT54GL wireless router represents the lower end of the performance spectrum. The technical platform is rather old (first released in 2002) and the router is still very popular due to its flexibility and the possibility of replacing the original firmware by a Linux-based third-party firmware. The TP-Link TLWR1043ND wireless router platform was released in 2008 and also targets the residential and home network market. It is based on an Atheros AR9132 SoC and offers both a fast wired and wireless network interface. Additionally, this platform is equipped with a USB 2.0 host controller that allows attaching different USB devices like mass storage devices for network sharing.

The Ubiquity Networks Routerstation Pro marks the top end of wireless router platforms under investigation. It is based on the Atheros AR7161 SoC, which is designed as a high performance wireless network processor that enables efficient designs for triple-play services. All of the platforms are based on MIPS CPUs which are running at clock rates ranging from 200 to 720 MHz. This range of the clock rates can be considered as representative for the wireless router platforms available at the time of writing. As an aside, the same series of SoCs (AR9132 and AR7161) are also used in wireless routers of other well-known vendors like D-Link, Netgear, Mikrotik, or Buffalo.

In order to have a common software ...