Essential Networking Protocols and Design Principles

Cabling and Network Design

Coax Cable: Less widely used than twisted-pair, expensive, harder to manage, and slower to connect.

Secure Design Modularity (Belt and Suspenders):

• Network security should be multilayered.
• Securing all components of a modular design: internet connections, e-commerce.

Hierarchy Network Design Strategy:

• A useful high-level tool for designing a reliable network.
• Used to group devices into multiple networks.
• Consists of Access, Core, and Distribution layers.

Network Performance and Errors

Runt: A packet that is below the minimum size for a given protocol.

Jabber: A packet that is greater than the maximum size for a given protocol.

Authentication Protocols

EAP (Extensible Authentication Protocol): Involves a supplicant, an authenticator, and an authentication server.

PEAP (Protected Extensible Authentication Protocol): Most widely used in WLAN; creates an outer TLS tunnel and uses a server-side certificate.

EAP-FAST: Flexible authentication protocol via secure tunneling.

WEP (Wired Equivalent Privacy): Defined by IEEE 802.11; encrypts data using the RC4 stream cipher.

Network Services and Connectivity

DHCP (Dynamic Host Configuration Protocol): Provides IP network addresses to clients using a client/server model. Supports three methods: Automatic, Dynamic, and Manual.

VPN (Virtual Private Network): Uses tunneling techniques to allow server connections between endpoints over public networks.

SONET (Synchronous Optical Network):

• A standard used for connecting fiber optics.
• Defines a hierarchy of interface rates that allow data streams at different rates to be multiplexed.
• Uses ring topologies; if a link fails, traffic is rerouted the other way around the link.

VLAN (Virtual LAN): Used when more than one device on the same LAN is configured for logical segmentation.

DMZ (Demilitarized Zone): A public LAN that hosts web, FTP, DNS, and SMTP servers.

ISDN (Integrated Services Digital Network): A standard for simultaneous digital transmission; a circuit-switched service.

PPP (Point-to-Point Protocol): A standard data link layer protocol used to establish a direct connection between two nodes; provides connection authentication.

MPPP (Multilink PPP): Used for load sharing; adds support for channel aggregation to PPP and ensures that packets arrive in order at the receiving device.

Routing and Management

IGMP (Internet Group Management Protocol): Allows a host to join a multicast group; the host transmits a membership-report message.

PAT (Port Address Translation): Used to conserve IP addresses.

IEEE 802.1Q: The IEEE standard for frame tagging.

OSPF (Open Shortest Path First): Adjusts to changes quickly, supports very large internetworks, does not use a lot of bandwidth, and authenticates protocol exchanges.

IS-IS (Intermediate System-to-Intermediate System): A link-state routing protocol designed by the ISO for OSI protocols; Integrated IS-IS handles IP as well.

Network Metrics

Adaptability: The ease with which a network design and implementation can adapt to new business goals.

Usability: The ease with which network users can access the network and its services.

Bandwidth: The data-carrying capacity of a circuit.