Brian HixenbaughNetwork Managment

My Home Network

My Plan…N.A.S. (1 TB External Hard Drive)

Connects to Router via Ethernet (Has IP Address)

Stores movies, television shows, etc.Laptop Connected to TV (Downstairs)

Wirelessly stream content from N.A.S. or Internet

Display on televisionRoommate’s Laptop (iPhone, etc.)

Independently use Internet or N.A.S. as well

It Works! (Almost)Need to Implement QoS (Quality of Service)

Router Inspects Packets – Prioritizes Video, VoIP

Low Priority – P2PImprove Radio Performance

Increase TX power, Increase Beacon IntervalExpensive Commercial Routers Offer These

FeaturesCheap home routers can offer these features as

well with replacement software!

Embedded SystemsA Router is a “Mini” Computer with:

CPURAMHard Drive (Flash Chip)

Open Source Software Can Replace Factory Software to Provide More FeaturesOpenWRTTomatoDD-WRT

Netgear WGR614

DD-WRT

“Flashing” New SoftwareSimilar to a PC

Boot program (CFE)Kernal (linux!)Software (dd-wrt)

Upload via Router’s Web GUI (Ethernet)Software not always compatible with all makes

& models of routersFlash memory locations can be differentThere can be problems!

Bricked

Fix a Brick with JTAGJoint Test Action Group or Boundary-Scan

IEEE Standard for communicating with embedded systems

Allows issuing commands directly to ProcessorAllows directly programming Flash Memory

Allows a PC to Communicate for DebuggingRequires parallel port on PC, special interface

device, and communication software

Common Firmware EnvironmentCFE contains information for Ethernet (MAC

addr.)Also contains information to boot Kernal

If damaged, must be replaced by JTAGCFE is small (~128k) but JTAG is slow – can take

5-10 minutes to uploadKernal & software are much larger (2-3MB) not

practical to send via JTAGOnce CFE is uploaded and running, remaining

software can be quickly flashed via Ethernet using TFTP (Trivial File Transfer Protocol)

No Happy EndingCould not

successfully reload factory softwarePossible hardware

problems (bad flash chip, CPU)

Still a Brick!