1	Interconnecting Cisco Networking Devices Module 2 TCP/IP and Subnetting
2	TCP/IP Overview OSI vs. TCP/IP Transmission Control Protocol (TCP) User Datagram Protocol (UDP) Port #s Internet Control Message Protocol (ICMP) Address Resolution Protocol (ARP) Binary to Decimal and Hexadecimal Conversion Intro To Network Access Translation (NAT) Summary
3	OSI vs. TCP/IP
4	Transmission Control Protocol (TCP) Provides reliable delivery of data “Connection-Oriented” Error Checking Uses Sequence #s Ex. FTP, Telnet
5	User Datagram Protocol (UDP) “Thin Protocol” “Connectionless” No Error Checking Great for apps that don’t care about whether data gets there. Ex. DNS, DHCP, SNMP
6	Port #s Ports were created so a server could run many services at once. Ex. Web server, e-mail server, DNS server, etc. Port #s are used for “Multiplexing” Servers use Well-Known port #s, such as port 80 for web traffic Hosts dynamically create private port #s so when data is returned, it is handled by the correct application
7	Internet Control Message Format (ICMP) Handles ping, and traceroute, among other troubleshooting apps Operates at the (L3) Network Layer
8	Address Resolution Protocol (ARP) Finds the hardware (MAC) address of a host from the IP Address Local host broadcasts on the local network to discover destination host Every host maintains an ARP Cache This is typical on every network Most commonly you’ll see hosts trying to find servers
9	Binary to Decimal Conversion Based on Powers of 2
10	Decimal to Hex Conversion Based on Powers of 16
11	Intro to NAT Translates addresses from the inside (private) network, to the outside (public) network Effectively saved us from running out of IP Addresses years ago
12	NAT Flavors Static NAT Dynamic NAT Overloading (Most Popular) Also known as Port Address Translation (PAT)
13	NAT Example
14	Summary OSI vs. TCP/IP Transmission Control Protocol (TCP) User Datagram Protocol (UDP) Port #s Internet Control Message Protocol (ICMP) Address Resolution Protocol (ARP) Binary to Decimal and Hexadecimal Conversion Intro To Network Access Translation (NAT) Summary
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16	TCP/IP Subnetting Part II IP Addressing (Classes, Private Addresses, Other Addresses) How to Subnet Classful / Classless Subnetting Variable Length Subnet Masks (VLSM)
17	IP Addressing - Classes
18	IP Addressing – Private Addresses 10.0.0.0 - 10.255.255.255 172.16.0.0 - 172.31.255.255 192.168.0.0 - 192.168.255.255 Automatic Private IP Addressing (APIPA) 169.254.0.0 -169.254.255.255
19	IP Addressing – Others Network Address: The first address in the range Broadcast Address: The last address in the range
20	Why Subnet Reduced Network Traffic Optimized Network Performance Simplified Management Facilitated Spanning of Large Geographical Distances
21	How to Subnet Determine # of required Network IDs One for each subnet One for each wide area network connection Determine # of required Hosts One for each TCP/IP Host One for each router interface Based on the above, create: One subnet mask for your entire network A unique subnet ID for each physical segment A range of host IDs for each subnet
22	Classful Subnet Masks
23	Classless Inter-Domain Routing (CIDR) Typically the ISP issues these in ‘slash notation’ 150.150.54.0/28 Once you receive an IP, you usually subnet it down for your hosts / networks by ‘stealing bits’
24	TCP/IP Subnetting Use 2^x-2 to find how many bits to convert (x = # of bits) Convert subnet mask to dotted decimal notation Use 2^x-2 to find # of hosts per sub-network (x = # of bits left untouched) Subtract value of fractional octet from 256 (result is the increment) Use increment to determine address ranges Discard first and last sub-network Discard first and last address in each sub-network
25	Question: Why would a network engineer use a subnet of 255.255.255.252?
26	Variable Length Subnet Masks (VLSM) Allows you to have different subnet masks for each subnetwork “Summarization of Routes” Also called “Supernetting”
27	Implementing VLSM Networks Understanding Block Sizes Block Size = Increment To do VLSM you simply start w/ a blank chart, and counting at 0 work your way up. Most common example is the 255.255.255.252 subnet which handles two hosts, i.e. a router to router connection.
28	Troubleshooting IP Addressing Ping 127.0.0.1 Ping IP address of the local host Ping the default gateway (router) Ping a remote server DNS Errors are common. Ping your DNS servers as well
29	Summary IP Addressing (Classes, Private Addresses, Other Addresses) How to Subnet Classful / Classless Subnetting Variable Length Subnet Masks (VLSM)