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  • PPP contains three main components: 1) a method for encapsulating datagrams over serial links - PPP uses HDLC protocol as a basis for encapsulating datagrams over point-to-point links. 2) An extensible LCP to establish, configure, and test the data-link connection 3) A family of NCPs for establishing and configuring different network layer protocols - PPP is designed to allow the simultaneous use of multiple layer protocols.
  • PPP contains three main components: 1) a method for encapsulating datagrams over serial links - PPP uses HDLC protocol as a basis for encapsulating datagrams over point-to-point links. 2) An extensible LCP to establish, configure, and test the data-link connection 3) A family of NCPs for establishing and configuring different network layer protocols - PPP is designed to allow the simultaneous use of multiple layer protocols.
  • ISDN is a digital service designed to run over existing telephone networks. A true digital service over existing local loop. It can support both data and voice required bandwidth. Specialized ISDN terminals are referred to as terminal equipment type 1. Non-ISDN terminals, such as DTE, that predate the ISDN standards are referred to as terminal equipment type 2 and require a terminal adapter. These connect to the ISDN network through a four-wire, twisted-pair digital link. Beyond the TE1 and TE2 devices, the next connection point in the ISDN networks is the network termination devices that connect the four-wire subscriber wiring to the conventional two-wire local loop. The ISDN Basic Rate Interface (BRI) service offers two B channels and one D channel (2B+D) BRI B-channel service operates at 64 kbps and is meant to carry user data; BRI D-channel service operates at 16 kbps and is meant to carry control and signaling information. BRI also provides for framing control bringing its total bit rate to 192 kbps. ISDN Primary Rate Interface (PRI) services offers 23 B channels and one D channel for a total bit rate of 1.544.
  • Frame relay has become one of the most popular WAN protocols available over the past few years. For a number of reasons, frame relay has been attractive as an inexpensive way to connect a large number of sites. One of the reasons frame relay has become attractive is the concept of shared bandwidth. Instead of giving everyone their own dedicated bandwidth (leased line), all customers share access to the total bandwidth available through the frame relay cloud. With hundreds of customers sharing the total pipe, utilization is much more efficient and, thus, less expensive than leased lines for both telephone companies and customers. Popular opinion is that frame relay is faster and more efficient than X.25 because it assumes that error checking will be done through higher-layer protocols and application services. Frame Relay provides connection-oriented data link layer communication. This means that a defined communication exists between each pair of devices and that these connections are associated with a connection identifier (DLCI)r. This service is implemented by using a frame relay virtual circuit, which is a logical connection created between two data terminal equipment (DTE) devices across a frame relay pack-switched network.
  • Dedicated: Synchronous serial High volume environments with steady rate of traffic. Long connect times but shorter distances. Not shared so more costly. Use for real time data Full time connectivity between LANs Uses a csu/dsu 56k, 64k to 45 mbps (T3) Point to point connections that are indefinitely reserved for transmission rather than being switched as transmissions is required. Reserved full time. Circuit Asynchronous serial, ISDN Low volume, traffic patters periodic Call setup and tear down Check email by mobile user; dial into the internet for an hour and than log out; backup system Physical circuit paths that are established only during the duration of the call. Once the circuit is formed, all data travels the same path. 28k to 56K ISDN – increased bandwidth; voice, video BRI – 128 mbps PRI – 1.544 mbps Packet Switched Synchronous serial High link utilization; long connect times; large geographic distances Virtual circuits Shared bandwidth, lower cost Connection oriented Data is divided into packets which include a seq. # and destination address. The packets can travel different paths and are reassembled at the destination. Customers purchase a committed information rate from carrier to ensure min. rate of bandwidth.
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    1. 1. WANs and Routers Joanne Wagner CCNP, CCAI, Security+, CCSP
    2. 2. WAN OVERVIEW <ul><li>Used to connect LANs that are separated by a large geographic area </li></ul><ul><li>WAN protocols differ from LAN protocols mostly at the OSI Physical and Data Link Layers </li></ul>
    3. 3. The figure shows the relationship between the common WAN technologies and the OSI model
    4. 4. WAN CHARACTERISTICS <ul><li>Uses the services of Regional Bell Operating Companies (RBOC) for operational and functional connections </li></ul><ul><li>Unlike LANs, uses serial interfaces operating at lower speeds </li></ul>
    5. 5. WAN Line Types/Bandwidth
    6. 6. WAN Devices <ul><li>WAN Devices include: </li></ul><ul><ul><li>Routers </li></ul></ul><ul><ul><ul><li>Router offer many services, including internetworking and WAN interface ports. </li></ul></ul></ul><ul><ul><li>Switches </li></ul></ul><ul><ul><ul><li>Switch in the WAN provide connectivity for voice, data, and video communication. </li></ul></ul></ul><ul><ul><li>Modems </li></ul></ul><ul><ul><ul><li>Include interface voice-grade services, </li></ul></ul></ul><ul><ul><ul><li>channel service units/digital service units (CSU/DSUs) that interface T1/E1 services, </li></ul></ul></ul><ul><ul><ul><li>Terminal Adapters/Network Termination 1 (TA/NT1s) </li></ul></ul></ul><ul><ul><li>Communication servers </li></ul></ul><ul><ul><ul><li>Concentrate dial-in/dial-out user communication. </li></ul></ul></ul>
    7. 7. Introduction to WANs <ul><li>Organizations who provide us with most of our WAN standards and protocols: </li></ul><ul><ul><ul><li>International Telecommunications Union (ITU) </li></ul></ul></ul><ul><ul><ul><li>International Organization for Standards (ISO) </li></ul></ul></ul><ul><ul><ul><li>Internet Engineering Task Force (IETF) </li></ul></ul></ul><ul><ul><ul><li>Electronic Industries Association (EIA) </li></ul></ul></ul>
    8. 8. WANs: Physical Layer <ul><li>DTE (Data Terminal Equipment) is the device at the user end of a user-network interface that serves as a data source, destination, or both. </li></ul><ul><li>DTE connects to a data network through a DCE device and typically uses clocking signals generated by the DCE. </li></ul><ul><li>DTE includes such devices as routers, computers, protocol translators, and multiplexers. </li></ul>
    9. 9. WANs: Physical Layer <ul><li>DCE - Data communications equipment (EIA expansion) or data circuit-terminating equipment (ITU-T expansion). </li></ul><ul><li>The DCE provides a physical connection to the network, forwards traffic, and provides a clocking signal used to synchronize data transmission between DCE and DTE devices. Ex: Modems and CSU/DSUs </li></ul>Hint: Use router# show controller serial 0/0 to find out if a cable is a DTE or a DCE
    10. 10. WAN Physical Layer Standards <ul><li>EIA/TIA-232 </li></ul><ul><li>EIA/TIA-449 </li></ul><ul><li>V.24 </li></ul><ul><li>V.35 </li></ul><ul><li>X.21 </li></ul><ul><li>ISDN </li></ul><ul><li>T1,T3, E1 and E3 </li></ul><ul><li>SONET (OC-3, OC-12, OC-48, OC-192) </li></ul>
    11. 12. WANs: DATA LINK LAYER <ul><li>Define how frames are carried between systems on a single data link: </li></ul><ul><li>High-Level Data Link Control (HDLC) </li></ul><ul><li>Frame Relay </li></ul><ul><ul><li>LAPF </li></ul></ul><ul><li>Point-to-Point (PPP) </li></ul><ul><li>Integrated Services Digital Network (ISDN) </li></ul><ul><ul><li>LAPD </li></ul></ul><ul><ul><li>LAPB </li></ul></ul><ul><li>X.25 </li></ul>
    12. 13. WAN Data Link Protocols: HDLC <ul><li>The Cisco default serial line encapsulation type. </li></ul><ul><li>It is used when communicating with another Cisco device. </li></ul><ul><li>If communicating with a non-Cisco device, synchronous PPP is a viable option. </li></ul><ul><li>HDLC is normally proprietary between vendors . There is no windowing or flow control. </li></ul>
    13. 14. WAN DATA LINK PROTOCOLS: PPP <ul><li>Provides router-to-router (LAN to LAN) and host-to-network connections over synchronous and asynchronous circuits </li></ul><ul><li>Standardized so it supports vendor interoperability </li></ul><ul><li>Contains a protocol field to identify the network protocol </li></ul>
    14. 15. WAN DATA LINK PROTOCOLS: PPP <ul><li>The Point-to-Point Protocol (PPP) is a standard serial line encapsulation method which includes: </li></ul><ul><ul><ul><li>Protocol type field </li></ul></ul></ul><ul><ul><ul><li>Link Control Protocol - This protocol can, among other things, check for link quality during connection establishment. </li></ul></ul></ul><ul><ul><ul><li>Support for authentication through the Password Authentication Protocol (PAP) and the Challenge Handshake Authentication Protocol (CHAP) </li></ul></ul></ul>
    15. 16. Comparing WAN Frame Encapsulation Formats
    16. 17. DATA LINK PROTOCOLS: ISDN <ul><li>A digital circuit-switched service that transmits voice and data over existing telephone lines </li></ul><ul><li>ISDN applications include high-speed image applications, high-speed file transfer, video conferencing, and voice service </li></ul>
    17. 18. DATA LINK PROTOCOLS: ISDN <ul><li>ISDN services: </li></ul><ul><li>Basic Rate Interface (BRI) </li></ul><ul><ul><ul><li>Operates over most copper twisted-pair telephone wiring in place today. </li></ul></ul></ul><ul><ul><ul><li>Delivers a total bandwidth of a 144-kbps line into three separate channels. </li></ul></ul></ul><ul><li>Primary Rate Interface (PRI) </li></ul>
    18. 19. <ul><li>ISDN BRI </li></ul><ul><li>Two of the channels , called B (bearer) channels , operate at 64 kbps and are used to carry voice or data traffic . </li></ul><ul><li>The third channel , the D (data) channel , is a 16-kbps signaling channel used to carry instructions that tell the telephone network how to handle each of the B channels. </li></ul><ul><li>Often referred to as “ 2B+D .” </li></ul>
    19. 20. DATA LINK LAYER PROTOCOLS: FRAME RELAY <ul><li>Uses high quality digital facilities with no error correction </li></ul><ul><li>More efficient than X.25 </li></ul><ul><li>A packet-switched technology that enables end stations to dynamically share the network medium and the available bandwidth </li></ul>
    20. 21. <ul><li>Frame Relay: </li></ul><ul><li>Designed with higher speed. </li></ul><ul><li>As a result, Frame Relay contains a limited amount of error checking and reliability features. </li></ul><ul><li>Upper-layer protocols are expected to attend to these issues. </li></ul><ul><li>Most common packet-switched network type </li></ul>DATA LINK LAYER PROTOCOLS: FRAME RELAY
    22. 23. WAN PROTOCOLS:
    23. 24. <ul><li>Dedicated connectivity, also referred to as leased lines, provides full-time synchronous connections. </li></ul><ul><li>Dedicated, full-time connectivity is provided by point-to-point serial links. </li></ul><ul><li>The cost of dedicated line solutions can become significant when deployed to connect many sites, which is especially true if full meshing is desired. </li></ul>Connection Type: Dedicated (Leased)
    24. 25. <ul><li>Leased lines of this type are ideal for high-volume environments with a steady-rate traffic pattern. </li></ul><ul><li>Use of available bandwidth is a concern because the cost of the line is paid even when the connection is idle. </li></ul>Connection Type: Dedicated (Leased)
    25. 26. Connection Type: Dedicated (Leased) T1 is a dedicated WAN technology
    26. 27. Connection Type: Dedicated (Leased)
    27. 28. Dedicated leased lines are a reasonable design option for the core WAN
    28. 29. <ul><li>Used primarily to: </li></ul><ul><li>connect remote users </li></ul><ul><li>mobile users to corporate LANs. </li></ul><ul><li>backup lines for higher-speed circuits, such as Frame Relay and dedicated lines. </li></ul>Connection Type: Circuit-Switched
    29. 30. <ul><li>brought up when needed </li></ul><ul><li>generally low bandwidth </li></ul><ul><li>Basic Telephone Service connections are generally limited to 28.8 kbps without compression, ISDN to 64 or 128 kbps . </li></ul>Connection Type: Circuit-Switched
    30. 31. <ul><li>There are two ISDN services </li></ul><ul><li>Basic Rate Interface (BRI) </li></ul><ul><li>Primary Rate Interface (PRI) </li></ul><ul><li>ISDN BRI </li></ul><ul><li>operates over most of the copper twisted-pair telephone wiring in place today. </li></ul><ul><li>delivers a total bandwidth of a 144-kbps line into three separate channels . </li></ul>Connection Type: Circuit-Switched
    31. 32. Connection Type: Circuit-Switched <ul><li>ISDN provides great flexibility to the network designer because of its ability to use each of the B channels for separate voice or data applications : </li></ul><ul><ul><li>Example , a long document can be downloaded from the corporate network over one ISDN 64-kbps B channel while the other B channel is being used to connect to browse a World Wide Web page. </li></ul></ul><ul><ul><li>Care should be taken in the design phase to ensure that the equipment selected has the feature set that takes advantage of ISDN’s flexibility. </li></ul></ul>
    32. 34. Connection Type: Frame Relay <ul><li>Information contained in packets or frames </li></ul><ul><li>Shares non-dedicated bandwidth with other WAN subscribers' frames. </li></ul><ul><li>A WAN switch forwards Frame Relay and X.25 traffic. </li></ul>
    33. 35. Connection Type: Frame Relay <ul><li>X.25 can use Switched Virtual Circuits (SVCs), with some initial delay for call setup, or Permanent Virtual Circuits (PVCs) which avoid delays for call setup . </li></ul><ul><li>Frame Relay uses Layer 2 identifiers and Permanent Virtual Circuits (PVCs). </li></ul>
    34. 36. Connection Type: Frame Relay <ul><li>Frame Relay defines the connection between a customer DTE and a carrier DCE. </li></ul><ul><li>The DTE is typically a router or FRAD ( Frame Relay access devices) </li></ul><ul><li>The DCE is a Frame Relay switch. </li></ul><ul><li>Frame Relay access is at: </li></ul><ul><li>56 kbps, 64 kbps, or 1.544 Mbps </li></ul>
    35. 37. Frame Relay Cost Effective:
    36. 38. A packet switched line is used to share a single point-to-point link to transport packets.
    39. 41. WAN link options are classified as dedicated and switched WAN TECHNOLOGY SUMMARY:
    41. 43. Internal Configuration Components
    42. 44. WANs – The Router <ul><li>A router is a special type of computer. It has </li></ul><ul><ul><ul><li>CPU </li></ul></ul></ul><ul><ul><ul><li>memory, </li></ul></ul></ul><ul><ul><ul><li>a system bus, </li></ul></ul></ul><ul><ul><ul><li>various input/output interfaces. </li></ul></ul></ul><ul><li>Routers are designed to perform some very specific functions. </li></ul><ul><ul><ul><li>routers connect and allow communication between two networks and determine the best path for data to travel through the connected networks. </li></ul></ul></ul>
    43. 45. WANs – The Router <ul><li>A Routers Requires: </li></ul><ul><ul><ul><li>Internetwork Operating System software (IOS) </li></ul></ul></ul><ul><ul><ul><li>CPU </li></ul></ul></ul><ul><ul><ul><li>Configuration file </li></ul></ul></ul>
    44. 46. Introduction to routers in a WAN <ul><li>The main internal components of the router are </li></ul><ul><ul><ul><li>Random access memory (RAM), </li></ul></ul></ul><ul><ul><ul><ul><li>Stores routing tables </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Holds ARP cache </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Holds fast-switching cache </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Performs packet buffering (shared RAM) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Maintains packet-hold queues </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Provides temporary memory for the configuration file while the router is powered on ( stores running configuration file ) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Loses content when router is powered down or restarted </li></ul></ul></ul></ul><ul><ul><ul><li>Nonvolatile random-access memory (NVRAM), </li></ul></ul></ul><ul><ul><ul><ul><li>Provides storage for the startup configuration file which </li></ul></ul></ul></ul><ul><ul><ul><li>contains the instructions that a router uses to control the flow of traffic through its interfaces </li></ul></ul></ul><ul><ul><ul><ul><li>Retains content when router is powered down, restarted, or power is lost. </li></ul></ul></ul></ul>
    45. 47. <ul><li>The main internal components (continued) </li></ul><ul><ul><li>Flash memory, </li></ul></ul><ul><ul><ul><li>Holds or stores the Cisco operating system image (IOS) </li></ul></ul></ul><ul><ul><ul><li>Allows software to be updated without removing and replacing chips on the processor </li></ul></ul></ul><ul><ul><ul><li>Retains content when router is powered down or restarted </li></ul></ul></ul><ul><ul><ul><li>Can store multiple versions of IOS software </li></ul></ul></ul><ul><ul><ul><li>Is a type of electronically erasable, programmable ROM (EEPROM) </li></ul></ul></ul><ul><ul><li>Read-only memory (ROM), and </li></ul></ul><ul><ul><ul><li>Maintains instructions for power-on self test (POST) diagnostics </li></ul></ul></ul><ul><ul><ul><li>Stores bootstrap program and basic operating system software </li></ul></ul></ul><ul><ul><ul><li>Requires replacing pluggable chips on the motherboard for software upgrades </li></ul></ul></ul><ul><ul><li>Interfaces. </li></ul></ul><ul><ul><ul><li>Network connection through which packets enter and leave the router </li></ul></ul></ul><ul><ul><ul><li>Connect router to network for frame entry and exit </li></ul></ul></ul><ul><ul><ul><li>Can be on the motherboard or on a separate module </li></ul></ul></ul><ul><ul><ul><li>Connects the router to LANs and WANs </li></ul></ul></ul>Introduction to routers in a WAN
    46. 48. Router LANs and WANs <ul><li>Routers have both LAN and WAN interfaces. </li></ul><ul><ul><li>While a router can be used to segment LANs, its major use is as a WAN device. </li></ul></ul><ul><li>Routers are the backbone devices of large intranets and of the Internet. </li></ul><ul><ul><li>They operate at Layer 3 of the OSI model, making decisions based on network addresses. </li></ul></ul><ul><li>The two main functions of a router are </li></ul><ul><ul><li>the selection of best path for and </li></ul></ul><ul><ul><li>the switching of frames to the proper interface. </li></ul></ul><ul><li>Routers accomplish this by building routing tables and exchanging network information with other routers. </li></ul>
    47. 49. Router LANs and WANs (cont.) <ul><li>An administrator can maintain routing tables by </li></ul><ul><ul><li>configuring static routes , </li></ul></ul><ul><ul><li>but generally routing tables are maintained dynamically through the use of a routing protocol that exchanges network topology (path) information with other routers. </li></ul></ul><ul><li>A correctly configured internetwork provides the following: </li></ul><ul><ul><li>Consistent end-to-end addressing </li></ul></ul><ul><ul><li>Addresses that represent network topologies </li></ul></ul><ul><ul><li>Best path selection </li></ul></ul><ul><ul><li>Dynamic or static routing </li></ul></ul><ul><ul><li>Switching </li></ul></ul>
    48. 50. Router internal components <ul><li>CPU </li></ul><ul><li>RAM </li></ul><ul><li>Flash </li></ul><ul><li>NVRAM </li></ul><ul><li>Buses </li></ul><ul><li>ROM </li></ul><ul><li>Interfaces </li></ul><ul><li>Power Supply </li></ul>
    49. 51. Router internal components <ul><li>CPU – The Central Processing Unit (CPU) executes instructions in the operating system. </li></ul><ul><li>RAM – Random-access memory (RAM) is used for routing table information, fast switching cache, running configuration, and packet queues. </li></ul><ul><ul><ul><li>RAM provides run time space for executable Cisco IOS software and its subsystems. </li></ul></ul></ul><ul><ul><ul><li>RAM is usually logically divided into main processor memory and shared input/output (I/O) memory. </li></ul></ul></ul><ul><ul><ul><li>Shared I/O memory is shared among interfaces for temporary storage of packets. The contents of RAM are lost when power is removed. </li></ul></ul></ul><ul><ul><ul><li>RAM is generally dynamic random-access memory (DRAM) and can be upgraded by adding additional Dual In-Line Memory Modules (DIMMs). </li></ul></ul></ul>
    50. 52. Router internal components (cont.) <ul><li>Flash – Flash memory is used for storage of a full Cisco IOS software image. </li></ul><ul><ul><ul><li>The router normally acquires the default IOS from flash. </li></ul></ul></ul><ul><ul><ul><li>These images can be upgraded by loading a new image into flash. </li></ul></ul></ul><ul><ul><ul><li>The IOS may be in uncompressed or compressed form. </li></ul></ul></ul><ul><ul><ul><li>In most routers an executable copy of the IOS is transferred to RAM during the boot process. </li></ul></ul></ul><ul><ul><ul><li>In other routers the IOS may be run directly from flash. </li></ul></ul></ul><ul><ul><ul><li>Adding or replacing the flash Single In-Line Memory Modules (SIMMs) or PCMCIA cards can upgrade the amount of flash. </li></ul></ul></ul>
    51. 53. Router internal components (cont.) <ul><li>NVRAM – Nonvolatile random-access memory (NVRAM) is used to store the startup configuration. </li></ul><ul><ul><li>In some devices, NVRAM is implemented using separate electronically erasable programmable read-only memory (EEPROMs) in some devices. </li></ul></ul><ul><ul><li>In other devices it is implemented in the same flash device from which the boot code is loaded. </li></ul></ul><ul><ul><li>In either case these devices retain contents when power is removed. </li></ul></ul><ul><li>Buses – Most routers contain a system bus and a CPU bus. </li></ul><ul><ul><li>The system bus is used for communication between the CPU and the interfaces and/or expansion slots. This bus transfers the packets to and from the interfaces. </li></ul></ul><ul><ul><li>The CPU bus is used by the CPU for accessing components from router storage. This bus transfers instructions and data to or from specified memory addresses. </li></ul></ul>
    52. 54. Router internal components (cont.) <ul><li>ROM – Read-only memory (ROM) is used for permanently storing startup diagnostic code (ROM Monitor). </li></ul><ul><ul><li>The main tasks for ROM are hardware diagnostics during router bootup and loading the Cisco IOS software from flash to RAM. </li></ul></ul><ul><ul><li>Some routers also have a scaled down version of the IOS that can be used as an alternative boot source. </li></ul></ul><ul><ul><li>ROMs are not erasable. They can only be upgraded by replacing the ROM chips in the sockets. </li></ul></ul><ul><li>Power Supply – The power supply provides the necessary power to operate the internal components. </li></ul><ul><ul><li>Larger routers may use multiple or modular power supplies. </li></ul></ul><ul><ul><li>In some of the smaller routers the power supply may be external to the router. </li></ul></ul>Router internal components (cont.)
    53. 55. Router internal components (cont.) <ul><li>Interfaces – The interfaces are the router connections to the outside. </li></ul><ul><ul><li>The three types of interfaces are </li></ul></ul><ul><ul><li>local-area network (LANs), </li></ul></ul><ul><ul><ul><li>The LAN interfaces are usually either Ethernet or Token Ring. </li></ul></ul></ul><ul><ul><ul><li>These interfaces have controller chips that provide the logic for connecting the system to the media. </li></ul></ul></ul><ul><ul><ul><li>The LAN interfaces may be a fixed configuration or modular. </li></ul></ul></ul><ul><ul><li>wide-area network (WANs), </li></ul></ul><ul><ul><ul><li>The WAN interfaces include serial, ISDN, and integrated Channel Service Unit (CSUs). </li></ul></ul></ul><ul><ul><ul><li>As with LAN interfaces, WAN interfaces also have special controller chips for the interfaces. </li></ul></ul></ul><ul><ul><ul><li>The WAN interfaces may be a fixed configuration or modular. </li></ul></ul></ul><ul><ul><li>Console/AUX. </li></ul></ul><ul><ul><ul><li>The Console/AUX ports are serial ports used primarily for the initial configuration of the router. </li></ul></ul></ul><ul><ul><ul><li>These ports are not networking ports . </li></ul></ul></ul><ul><ul><ul><li>They are used for terminal sessions from the communication ports on the computer or through a modem. </li></ul></ul></ul>
    54. 56. Router physical characteristics <ul><li>It is not critical to know the location of the physical components inside the router to understand how to use the router. </li></ul><ul><li>However in some situations, such as adding memory, it can be very helpful. </li></ul><ul><li>The exact components used and their location varies between router models. Figure identifies the internal components of a 2600 router. </li></ul><ul><li>Figure shows some of the external connectors on a 2600 router. </li></ul>
    55. 57. Router external connections <ul><li>The three basic types of connections on a router are LAN interfaces, WAN interfaces, and management ports. </li></ul><ul><ul><li>LAN interfaces – </li></ul></ul><ul><ul><ul><li>LAN interface allow the router to connect to the Local Area Network media. This is usually some form of Ethernet. </li></ul></ul></ul><ul><ul><ul><li>However, it could be Token Ring or Asynchronous Transfer Mode (ATM). </li></ul></ul></ul><ul><ul><li>WAN interfaces – </li></ul></ul><ul><ul><ul><li>Wide Area Network connections provide connections through a service provider to a distant site or to the Internet. </li></ul></ul></ul><ul><ul><ul><li>These may be serial connections or any number of other WAN interfaces. </li></ul></ul></ul><ul><ul><ul><li>With some types of WAN interfaces, an external device such as a CSU is required to connect the router to the local connection of the service provider. </li></ul></ul></ul><ul><ul><li>Management interfaces – </li></ul></ul><ul><ul><ul><li>The management port provides a text-based connection for the configuring, monitoring and troubleshooting of the router. </li></ul></ul></ul><ul><ul><ul><li>The common management interfaces are the console and auxiliary ports. These are EIA-232 asynchronous serial ports. </li></ul></ul></ul>
    56. 58. Management port connections <ul><li>The console port and the auxiliary (AUX) port are management ports. These asynchronous serial ports are not designed as networking ports . </li></ul><ul><li>One of these two ports is required for the initial configuration of the router. The console port is recommended for this initial configuration. </li></ul><ul><ul><li>When the router is first put into service, there are no networking parameters configured. </li></ul></ul><ul><ul><li>To prepare for initial startup and configuration, attach an RS-232 ASCII terminal, or a computer emulating an ASCII terminal, to the system console port. </li></ul></ul><ul><ul><li>Then configuration commands can be entered to set up the router. </li></ul></ul><ul><li>Not all routers have an auxiliary port. </li></ul>
    57. 59. Management port connections <ul><li>Once this initial configuration is entered into the router through the console or auxiliary port, the router can then be connected to the network for troubleshooting or monitoring. </li></ul><ul><li>The router can also be configured from a remote location by dialing to a modem connected to the console or auxiliary port on the router. </li></ul><ul><li>The console port is also preferred over the auxiliary port for troubleshooting. </li></ul><ul><ul><li>This is because it displays router startup, debugging, and error messages by default. </li></ul></ul><ul><ul><li>The console port can also be used when the networking services have not been started or have failed. </li></ul></ul><ul><ul><li>Therefore, the console port can be used for disaster and password recovery procedures. </li></ul></ul>
    58. 60. Connecting console interfaces <ul><li>To connect to the console port, a rollover cable and a RJ-45 to DB-9 adapter are used to connect a PC. </li></ul><ul><ul><li>Cisco supplies the necessary adapter to connect to the console port. </li></ul></ul><ul><li>The PC or terminal must support VT100 terminal emulation. Terminal emulation software such as HyperTerminal is usually used. </li></ul><ul><li>To connect the PC to a router: </li></ul><ul><li>Configure terminal emulation software on the PC for: </li></ul><ul><ul><li>The appropriate com port </li></ul></ul><ul><ul><li>9600 baud </li></ul></ul><ul><ul><li>8 data bits </li></ul></ul><ul><ul><li>No parity </li></ul></ul><ul><ul><li>1 stop bit </li></ul></ul><ul><ul><li>No flow control </li></ul></ul><ul><li>Connect the RJ-45 connector of the rollover cable to the router console port. </li></ul><ul><li>Connect the other end of the rollover cable to the RJ-45 to DB-9 adapter. </li></ul><ul><li>Attach the female DB-9 adapter to a PC. </li></ul>
    59. 61. Connecting console interfaces When connected using the console interface, the computer is acting as a “dumb terminal”. <Router Output>
    60. 62. Connecting console interfaces
    61. 63. Connecting console interfaces <Router Output> <Router Output>
    62. 64. Connection LAN interfaces <ul><li>In most LAN environments, the router is connected to the LAN using an Ethernet or Fast Ethernet interface. </li></ul><ul><li>The router is a host that communicates with the LAN via a hub or a switch. A straight-through cable is used to make this connection. </li></ul><ul><li>A 10/100BaseTX router interface requires Category 5 or better, unshielded twisted-pair (UTP) regardless of the router type. </li></ul><ul><li>In some cases the Ethernet connection of the router is connected directly to the computer or to another router. For this type of connection, a crossover cable is required. </li></ul>
    63. 65. Connecting WAN interfaces (cont.) <ul><li>Perhaps the most commonly used router interfaces for WAN services are serial interfaces. Selecting the proper serial cable is as easy as knowing the answers to four questions: </li></ul><ul><ul><li>What is the type of connection to the Cisco device? </li></ul></ul><ul><ul><ul><li>The interface on the left is a Smart Serial interface. </li></ul></ul></ul><ul><ul><ul><li>The interface on the right is a DB-60 connection. </li></ul></ul></ul><ul><ul><li>Is the network system being connected to a DTE or DCE device? </li></ul></ul><ul><ul><ul><li>DTE and DCE are the two types of serial interfaces that devices use to communicate. </li></ul></ul></ul><ul><ul><ul><li>The key difference between these two is that the DCE device provides the clock signal for the communications on the bus. </li></ul></ul></ul><ul><ul><li>What signaling standard does the device require? </li></ul></ul><ul><ul><ul><li>For each different device, a different serial standard could be used. Each standard defines the signals on the cable and specifies the connector at the end of the cable. </li></ul></ul></ul><ul><ul><li>Is a male or female connector required on the cable? </li></ul></ul><ul><ul><ul><li>If the connector has visible projecting pins, it is male. </li></ul></ul></ul><ul><ul><ul><li>If the connector has sockets for projecting pins, it is female. </li></ul></ul></ul>
    64. 66. <ul><li>WANS operate over large geographic areas </li></ul><ul><li>WAN protocols and standards differ from LAN protocols mostly at the Physical and Data Link Layer of the OSI Model </li></ul><ul><li>WANS use routers, switches, modems, and communication servers </li></ul><ul><li>Console and/or Auxiliary ports on the router are used for initial configuration </li></ul><ul><li>The Console port is used for debugging, password recovery, and troubleshooting </li></ul><ul><li>Terminal emulation software (hyper terminal) is used to establish the connection between the router and PC for initial configuration </li></ul><ul><li>To establish a connection between the PC and router use a rollover cable, DB-9 connector and a RJ-45 connector </li></ul>Points to Remember
    65. 67. <ul><li>Management connections are non-network connections, are used for initial configuration, and are asynchronous serial ports. </li></ul><ul><li>Management connections are used for troubleshooting problems and monitoring the system </li></ul><ul><li>RAM stores routing tables, holds fast switching cache, stores the running configuration, holds ARP cache, and is lost when power is shut down </li></ul><ul><li>NVRAM stores the startup configuration and retains contents when powered down </li></ul><ul><li>FLASH memory stores the IOS software images. It may need to have memory added to hold multiple versions of the image </li></ul><ul><li>Interfaces connect the router to the network, connect LANs and WANs, and use the configuration files to control the flow of traffic through the interfaces </li></ul>Points to Remember (con’t)