Report: Cisco Router Boot Process, PPP vs. PPPoE Protocols Analysis

This report delves into the boot process of a Cisco router, detailing the three key steps: Power-On Self-Test (POST), finding and loading the IOS, and detecting and running the device's configuration file. It explains how the router initializes hardware, loads the bootstrap program, and subsequently the IOS from ROM into RAM. The report then contrasts two crucial network protocols: Point-to-Point Protocol (PPP) and Point-to-Point over Ethernet (PPPoE). It highlights that PPP establishes direct connections between two endpoints in the data link layer, while PPPoE encapsulates PPP frames within Ethernet frames. PPP is typically used for dial-up networking, whereas PPPoE is commonly used with broadband modems and DSL connections, enabling multiple connections to an ISP's gateway servers, and providing user authentication through usernames and passwords. The report emphasizes PPPoE's role in controlling access and providing encrypted data transmission for enhanced security.

Contents
Boot process of cisco router...................................................................................................1
Difference between PPP (point-to-point) and PPPoE (point-to-point over ethernet) and
their usage...............................................................................................................................3

Boot process of Cisco router
A router is a device in networking that forwards packets from one computer to another and
are connected together in a network. For a router to perform its function it has to be in power
mode which means booting process has to take place. The booting process of Cisco router
takes three steps; Power on self-test (POST), Find and load IOS, detect and run configuration
file of the device (Muniz & Ortega, 2011).
When the Cisco router is powered on, a software located in ROM chip performs POST
process checking various hardware elements which include the device CPU, RAM and the
NVRAM including its interfaces.
After the POST process is completed the bootstrap program is loaded from ROM into RAM
for execution. The bootstrap then reads the register value for configuration in order to find
out the boot up process of the router then locate Cisco IOS and loads it into RAM. If it does
not load the IOS in all areas the boot sequence will be dropped in ROMMON state and
troubleshooting to take place.
Upon loading of IOS it locates and loads device startup configurations files in NVRAM to
RAM as running configurations. When the startup configurations cannot be found, the
configuration dialog of the system will be initiated and if it is found, it will, therefore, be
ready for the user to carry out the configurations. The diagram below shows the process
involved in the boot process.

Difference between PPP (point-to-point) and PPPoE (point-to-point over ethernet) and their
usage.
Point to point and Point to point over Ethernet are networking protocols that facilitate
communication between two endpoints of a network.
The main difference between the two network protocols is that PPP protocols are found in
data link layer that sets a connection between two endpoints directly without any networking
device between it while PPPoE protocols are network protocols that encapsulate point to
point frames within Ethernet frames (Berry, Ratliff, Paradise, Kaiser and Adams, 2010.).
The PPP protocols provide reliable TCP connection majorly used between modems for dial-
up networking. It is also used for mobile phone systems and phone lines and enables the users
to have access to their internet service provider.
The PPPoE protocols were designed to be used together with broadband modems and digitals
subscriber line (DSL) line internet service. The DSL line enables the physical connection
between home, offices, school computers and routers or modems to the ISP. The PPPoE
enables several connections to the ISP’s internet gateway servers (Turnbull, 2012). Also,
through PPPoE, ISP can control access to various accounts through the passwords and
usernames. It also provides a direct connection between the users and the internet service
providers’ (ISP) . Gateway servers thereby enable ISP not to deal with switching or DHCP
connections. Also, in PPPoE, the data that is being transmitted is encrypted and compressed,
therefore, providing a higher state of authentication in the network connection.

References
Berry, B., Ratliff, S., Paradise, E., Kaiser, T. and Adams, M., 2010. PPP over Ethernet
(PPPoE) extensions for credit flow and link metrics (No. RFC 5578).
McQuerry, S., Jansen, D., & Hucaby, D. (2009). Cisco LAN Switching Configuration
Handbook: Cisc Cata Swit Conf Hand_2. Cisco Press.
Muniz, S., & Ortega, A. (2011). Fuzzing and debugging Cisco IOS. BlackHat Europe.
Turnbull, J.G., 2012. Introducing home area networks. BT technology journal, 20(2), pp.30-
38.