1. IIUSA – Internet Institute Switches & Routers Rick Livingood, MA, MCSE, CCNP IIUSA – Internet Institute

2. Section Objectives Overview of Switches and Routers in a Network Environment Switch Configuration Routing Basics and Configuration Displaying Router Information Troubleshooting Routers and Switches

3. IIUSA – Internet Institute Layer 3 (IP) Basics Provides ability to address devices with a logical address and route traffic not locally attached –Logical addresses are applied to source and destination nodes or devices –Paths are determined to forward data from a local device to a remote device on another network

4. IIUSA – Internet Institute Router Functionality Network A Network B Routing Table Network A e0 Network B e1 e0 e1 Routers Separate Broadcast Domains

5. IIUSA – Internet Institute Why a Logical Address Hierarchical addresses provide reachability across boundaries called subnets Similar to the phone system with area codes to differentiate geographical regions or zip codes to indicate different cities and towns A hierarchical logical computer address contains a network identifier and host or unit identifier

6. IIUSA – Internet Institute Network Segments The size of a network dictates traffic load and potential for overload As growth overwhelms a network (similar to cars crowding a highway), segments can be created to off load traffic Each new segment is autonomous of other network segments Without segmentation, all addressing would be done through a flat addressing scheme (MAC addressing) overwhelming segmentation discovery devices (routers)

7. IIUSA – Internet Institute Connectivity Between Segments Segments can communicate through devices that determine a path from one network to another over communications lines Devices (routers) can determine the best path in the case of multiple paths Paths or routes are stored in routing tables 172.16.0.0/24 is subnetted, 1 subnets C 172.16.1.0 is directly connected, Ethernet0 10.0.0.0/24 is subnetted, 2 subnets R 10.2.2.0 [120/1] via 10.1.1.2, 00:00:07, Serial2 C 10.1.1.0 is directly connected, Serial2 R 192.168.1.0/24 [120/2] via 10.1.1.2, 00:00:07, Serial2 Portion of a Routing Table

8. IIUSA – Internet Institute Network Layer Addressing Routers use a portion of the address to determination Network identification All hosts or devices within a given network segment are identified by a host portion of the address IP Addresses 172.16.10.100 Network IDHost ID

9. IIUSA – Internet Institute Path Determination Network layer determines BEST path from source to destination A router examines reported paths over links, determining best path from metrics associated with each path Best Path

10. IIUSA – Internet Institute IP Header Detail Data Version 4 Header Length 4 Type of Service 8 Total Length 16 Identification 16 Flags 3 Fragment Offset 13 Time to Live 8 Protocol (Upper Level) 8 Header Checksum 16 SourceIP Address 32 DestinationIP Address 32 IP Options Variable Data Padding (If Needed)

11. IIUSA – Internet Institute IP Address Numbering IP Addresses are 32 bits in length 17216122204... NetworkHost Each Octet is 8 bits in length, representing a byte 10101100000100000111101011001100

12. IIUSA – Internet Institute Converting IP Addresses from Binary to Decimal 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 128 64 32 16 8 8 4 4 2 2 1 1 8 Bits 255 Decimal Value Note: All 0s indicates a decimal 0, totaling 256 Decimal Values

13. IIUSA – Internet Institute Conversion Example 1 1 0 0 1 1 1 1 0 0 1 1 0 0 1 1 128 64 32 16 8 8 4 4 2 2 1 1 8 Bits 255 Decimal Value 128 + 32 + 16 + 4 + 1 181

14. IIUSA – Internet Institute IP Classes HHHNHHNNNHNN Class A Class B Class C - Network numbers are assigned by ARIN - Host numbers assigned by Network Administrators

15. IIUSA – Internet Institute Class A Notes Address range 1 to 126 Address 10 is reserved as a private address Address 127 is reserved for loopback purposes First bit begins with a 0 (zero) HHHN 0

16. IIUSA – Internet Institute Class B Notes Address range 128 to 191 Address 172.16 to 172.31 is reserved as a private address range First two bits begin with a 10 HHNN 10

17. IIUSA – Internet Institute Class C Notes Address range 192 to 223 Address 192.168 is reserved as a private address range First three bits begin with a 110 NHNN 110

18. IIUSA – Internet Institute Reserved Address Space network number0s (zeros) in the host portion of the address space is reserved for the network number –Example: 172.16.0.0 broadcast address1s in the host portion of the address is reserved for the broadcast address –Example: 172.16.255.255

19. IIUSA – Internet Institute A Case for Subnetting The original IP addressing scheme was sufficient for the early days of the internetworking environment As the Internet grew in the 1990s, addressing, using classful addressing became impractical Subnetting (classless) addressing became the answer for address space depletion

20. IIUSA – Internet Institute Subnetting Subnetting borrows host bits to increase the number of networks The number of hosts is reduced in proportion to the number of bits borrowed

21. IIUSA – Internet Institute A Subnetted Network Original Network 172.16.0.0 172.16.1.0 172.16.2.0 172.16.3.0 172.16.4.0 172.16.5.0

22. IIUSA – Internet Institute 16 Network Host 17200 10101100 11111111 10101100 00010000 11111111 00010000 00000000 10100000 00000000 Subnets not in use—the default 00000010 Subnet Mask without Subnets 172.16.2.160 255.255.0.0 Network Number Subnet Mask

23. IIUSA – Internet Institute Network number extended by eight bits Subnet Mask with Subnets 16 Network Host 172.16.2.160 255.255.255.0 17220 10101100 11111111 10101100 00010000 11111111 00010000 11111111 00000010 10100000 00000000 00000010 Subnet Network Number 128 192 224 240 248 252 254 255

24. IIUSA – Internet Institute Defining a Subnet Mask Convert the Number of Segments to Binary Count the Number of Required Bits Convert the Required Number of Bits to Decimal (High Order) 1 1 2 2 3 3 Example of Class B Address Number of Subnets Binary Value Convert to Decimal 6 0 0 0 0 0 1 1 0 = 6 (3 Bits) 4+2 255. 255. 224. 0 11111111111111111110000000000000 Subnet Mask Ignore the first bit borrowed, add the additional bits borrowed to determine the number of new subnets

25. IIUSA – Internet Institute Defining Subnet IDs 255 2240 1 1 1 1 1 1 1 0 0 0 0 00 0 0 0 00000000 = 0 00100000 = 32 01000000 = 64 01100000 = 96 10000000 = 128 10100000 = 160 11000000 = 192 11100000 = 224 1 1 2 2 3 3 Evaluate the bit patterns established within the subnetted region

26. IIUSA – Internet Institute Shortcut to Defining Subnet IDs List the Number of Bits (High Order) Used for Subnet Mask Convert the Bit with the Lowest Value to Decimal Increment the Value for Each Bit Combination 11000000 64 0 + 64 = 64 + 64 = 128 + 64 192 w.x.64.1w.x.127.254 w.x.128.1w.x.191.254 1 1 2 2 3 3

27. IIUSA – Internet Institute Defining Host IDs for a Subnet Subnet IDs Host ID Range Invalid x.y.32.1 – x.y.63.254 x.y.64.1 – x.y.95.254 x.y.96.1 – x.y.127.254 x.y.128.1 – x.y.159.254 x.y.160.1 – x.y.191.254 x.y.192.1 – x.y.223.254 Invalid x.y.32.1 – x.y.63.254 x.y.64.1 – x.y.95.254 x.y.96.1 – x.y.127.254 x.y.128.1 – x.y.159.254 x.y.160.1 – x.y.191.254 x.y.192.1 – x.y.223.254 Invalid 00000000 = 0 00100000 = 32 01000000 = 64 01100000 = 96 10000000 = 128 10100000 = 160 11000000 = 192 11100000 = 224 00000000 = 0 00100000 = 32 01000000 = 64 01100000 = 96 10000000 = 128 10100000 = 160 11000000 = 192 11100000 = 224 Each Subnet ID Indicates the Beginning Value in a Host Range The Ending Value Is One Less Than the Beginning Value of the Next Subnet ID

28. IIUSA – Internet Institute Network to Network Connectivity 172.16.1.0 172.16.2.0 172.16.3.0 172.16.4.0  Router strips off the data link header  Examines the network layer address  Consults the routing table to find the interface for the network 1 2 3

29. IIUSA – Internet Institute Network-Layer Protocol Operations Each router provides its services to support upper-layer functions X Y A B C ABC Physical Data Link Network Physical Data Link Network Physical Data Link Network Physical Data Link Network Transport Session Presentation Application Physical Data Link Network Transport Session Presentation Application

30. IIUSA – Internet Institute Routed Versus Routing Protocols  Routed Protocols  Routed Protocols – Any network protocol run on a workstation as a part of the network operating system that provides networking capabilities (Ex: TCP/IP)  Routing Protocols  Routing Protocols – Protocols run on a router to provide the ability for the router to share path information (Ex: RIP, IGRP)

31. IIUSA – Internet Institute Routing Protocols Interior Routing ProtocolsInterior Routing Protocols – support the sharing of routes or paths within the internal internetwork (Ex: RIP, IGRP, EIGRP, OSPF) Exterior Routing ProtocolsExterior Routing Protocols – support the sharing of routes or paths across large internetworks, such as the Internet (Ex: BGP and EGP)

32. IIUSA – Internet Institute Routing Metrics metricsAll routing protocols utilize metrics to characterize best path information –Hop Count –Bandwidth –Delay –Load –Reliability –Ticks (Novell) –Cost – generic definition of metric information

33. IIUSA – Internet Institute Static versus Dynamic Routes StaticStatic routes are established by a network administrator and manually input directly into the routing table DynamicDynamic routes are learned through the use of a Routing Protocol. Dynamic routes are adaptive. Changes to path availability or establishment of new paths are automatically shared with other routers

34. IIUSA – Internet Institute Routers A Router is a computer, with similar functionality Forwards packets, from incoming interface to outgoing interfaced, based on best path as determined by routes available in the routers Routing Table Segments a LAN into separate Broadcast Domains Must be used when connecting LANs across wide area network environment

35. IIUSA – Internet Institute Typical Router System Board Layout Primary Memory DRAM SIMM EthernetSerial ConsoleAUX Shared Memory Fixed DRAM System Code Flash or PROM Flash Card Slot Boot ROMS Polarization Notch Memory Types: RAM/DRAM NVRAM Flash Memory ROM

36. IIUSA – Internet Institute Typical Cisco Motherboard for a 2500 Series

37. IIUSA – Internet Institute Sources For Configuring Console Port Auxiliary Port Interfaces VTY 0 - 4 TFTP Server Dial-in Access with modems Network Management Station

38. IIUSA – Internet Institute Router and Switch Configuration