User:Itpastorn/dko/ccna1-3.1-10

Module 10 Routing Fundamentals and Subnets

Overview CCNA 1 - Module 10 (3.1)
 * Routed vz routing vz unrouted Protocols
 * Data encapsulation, as data is routed
 * Connectionless and connection-oriented
 * The IP packet fields
 * How data is routed, routing metrics
 * Compare and contrast different types of routing protocols
 * Metrics used by routing protocols
 * Uses for subnetting
 * Calculate subnet masks
 * Calculate subnet ID

Routable and routed protocols
Examples of routable protocols
 * IP
 * IPX
 * AppleTalk
 * DECnet
 * Banyan VINES
 * Xerox Network Systems (XNS).

Connectionless and connection-oriented delivery

 * Packet propagation within a router

Anatomy of an IP packet

 * Anatomy of an IPv4 packet
 * Anatomy of an IPv6 packet

Routing Protocols

 * Provides processes used to share route information
 * Allows routers to communicate with other routers to update and maintain the routing tables

Routing overview
"A router is a network layer device that uses one or more routing metrics to determine the optimal path along which network traffic should be forwarded."

Non-routable protocols have no layer 3 functionality. E.g. NetBEUI.

Routing vz Switching
Layer 3 vz. layer 2 (long distance vz. local calls)

Both have: The switch: The router:
 * ARP-tables
 * Uses MAC-addresses
 * Has CAM-tables
 * Forwards broadcasts
 * Uses IP-addresses
 * Has routing tables
 * Blocks broadcasts

Path determination

 * Compares the IP address of the packet to the IP tables
 * Obtained destination address from the packet.
 * Apply mask of first entry and compare
 * Forward if its a match
 * Otherwise repeat process for next entry in the table
 * No match at all?
 * Default route?
 * Yes. Use it!
 * No default route? The packet is discarded. (Perhaps) tell sender that destination is unreachable.

Routing tables
"A hierarchical address scheme is required for data transfers."
 * Protocol type
 * Next-hop associations
 * Routing metric
 * Outbound interfaces

Routing algorithms and metrics
Design goals: routing metrics
 * Optimization – "Select the best route" based on metrics.
 * Simplicity and low overhead – Simple algorithm = easy to process
 * Robustness and stability – can handle unusual or unforeseen circumstances
 * Flexibility – Adapt quickly to a changes
 * Rapid convergence - all routers should "agree" quickly
 * Bandwidth
 * Delay
 * Load
 * Reliability
 * Hop count
 * Ticks (Approximately 1/18 second)
 * Cost

IGP and EGP

 * IGP:
 * RIP
 * RIPv2
 * IGRP
 * EIGRP
 * OSPF
 * Intermediate System-to-Intermediate System (IS-IS) protocol
 * EGP:
 * BGP

Link state and distance vector

 * Distance-vector routing protocol
 * Path vector protocol
 * Link-state routing protocol

Introduction to and reason for subnetting
Subnets are not seen from outside. Traffic to all subnets may be directed to the net as a whole.
 * Manageability
 * Broadcast containment
 * Low-level security (routers as firewalls between subnets)

Establishing the subnet mask address
IPv4 subnetting reference
 * Number of usable host addresses
 * Requirement of the largest subnet

Applying the subnet mask

 * Classic (dotted) notation
 * CIDR notation

Additional resorces (besides Wikipedia)

 * How the Internet Layer Works at Learn Networking
 * How to Subnet a Network at Learn Networking

Navigation

 * Main page
 * Previous Module
 * Next Module