ITEC 275 Computer Networks – Switching, Routing, and WANs Week 4 Robert D’Andrea
Agenda • Learning Activities • Logging into the VMware View Client • Accessing the MIMIC Virtual Lab CCNA • Introduce Cisco IOS • Review week three • Week four
VMware View • Select VMWare View Client icon • Use warning • Click OK
Login • Login • Enter standard Franklin credentials
VM selection • Select ITEC 275 LC • Click “Connect”
Command: ? Exec commands: clear Reset functions clock Configure serial interface clock configure Enter configuration mode connect Open a terminal connection copy Copy from one file to another debug Debugging functions (see also 'undebug') delete Delete a file disable Turn off privileged commands disconnect Disconnect an existing network connection enable Turn on privileged commands erase Erase a filesystem exit Exit from the EXEC help Description of the interactive help system logout Exit from the EXEC no Negate a command or set its defaults ping Send echo messages reload Halt and perform a cold restart show Show running system information systat Display information about terminal lines
Command: Show ? interfaces Interface status and configuration ipIP information ipv6 IPv6 information isis IS-IS routing information location Display the system location logging Show the contents of logging buffers modemcap Show Modem Capabilities database privilege Show current privilege level protocols Active network routing protocols running-config Current operating configuration snmpsnmp statistics startup-config Contents of startup configuration terminal Display terminal configuration parameters users Display information about terminal lines version System hardware and software status access-lists List access lists aliases Display alias commands arpARP table backup Backup status buffers Buffer pool statistics cdpCDP information clock Display the system clock compress Show compression statistics configuration Contents of Non-Volatile memory controllers Interface controller status dialer Dialer parameters and statistics flash: display information about flash: file system frame-relay Frame-Relay information history Display the session command history hosts IP domain-name, lookup style, nameservers, and host table
Command: Configure Configure commands: access-list Add an access list entry alias Create command alias banner Define a login banner cdp Global CDP configuration subcommands class-map Configure QoS Class Map dialer-list Create a dialer list entry enable Modify enable password parameters end Exit from configure mode exit Exit from configure mode frame-relay global frame relay configuration commands help Description of the interactive help system hostname Set system's network name interface Select an interface to configure ip Global IP configuration subcommands ipv6 Global IPv6 configuration subcommands isdn ISDN configuration commands key Key management line Configure a terminal line logging Modify message logging facilities no Negate a command or set its defaults policy-map Configure QoS Policy Map router Enable a routing process snmp-server Modify SNMP parameters trunk Configure a trunk group username Establish User Name Authentication
WARNING! • Every VMware View Client login is a new session • Any previous work will be lost unless saved to a local drive • Any files uploaded for a project will have to be reloaded
Review Week Three • Characterize the infrastructure of the existing network - Develop a set of network maps - Learning the locations of major internetworking devices - Identify all network segments - Identify any standard methods for addressing and naming convention
Review Week Three • Document -Types and lengths of actual cable and fiber - Investigate architectural constraints - Investigate environmental constraints - Investigate important aspects of characterizing the network infrastructure.
Week Three Review How to begin characterizing? Top-down method that shows high-level to low-level information. Global WAN WAN to LAN Identify each campus network Buildings, floors, and rooms Location(s) of servers and main-frames Location(s) of routers and switches Location(s) of LANs and VLANs Create a map that displays network services
Review Week Three • Characterize the logical architecture - Develop network diagrams of the company - Develop modular block diagrams • Characterize the network addressing and naming • Characterize wiring and media - Develop wiring within buildings - Verify architecture and environmental constraints - Develop any wireless installations with a wireless site survey
Review Week Three • Baseline the existing network • Dedicate the right amount of time for the baseline • Record the existing networks errors • Record the existing networks packet/cell loss • Record the existing networks latency issues during normal operating times • Record the existing networks performance
Review Week Three Baseline the existing network Definition A benchmark that is used as a foundation for measuring or comparing current and past values. For example, a company wanting to measure the success of one of its product lines can use the number of units sold during the first year as a baseline from which to evaluate subsequent sales growth. In business, baselines and benchmarks serve a similar purpose.
Review Week Three • Analyze the network availability • Analyze the network utilization - Bandwidth used by applications - Bandwidth used by protocols • Analyze the network accuracy • Analyze the network efficiency • Analyze the delays and response times
Week Four • Characterize traffic flow - Involves identifying the sources and destinations - Analyzing the direction of traffic - Analyzing the symmetric of traffic
Week Four • Identify User Communities and Data Stores A user community is a group of workers who use a particular application. They can exist in a department or group of departments. A user communities chart (Table 4-1) should be utilized to record this type of information in. A data store (data sink) is an area in a network where application layer data resides. A data store can be a number of components; server, server farm, a storage-area network (SAN), main-frame, a tape backup unit, a digital video library, or where large quantities of data are stored.
Week Four • Documenting Traffic Flow of the Existing Network - Identify and characterize individual traffic flows between traffic source and stores. - To understand traffic flow better, read RFC 2722. http://ietf.org/rfc/rfcxxxx.txt - Measuring traffic flow behavior Characterize the behavior of existing networks Plan for network development and expansion Quantify network performance Verify the quality of network services Assign network usage to users and applications
Week Four Traffic Flow Measurement: RFC 2722 This document provides a general framework for describing network traffic flows, presents an architecture for traffic flow measurement and reporting, discusses how this relates to an overall network traffic flow architecture and indicates how it can be used within the Internet.
Week Four • Documenting traffic flow of the existing network - Flow has the following attributes: Direction Symmetry Routing path and routing options Number of packets Number of bytes Addresses for each end of the flow Characterizing the size of a flow by measuring the number of megabytes per second (MBps) with a protocol analyzer.
Week Four On an individualized level, traffic floe can be defined as protocol and application information transmitted between communicating entities during a single session. A communicating entity can be an end system (host), a network, or an autonomous system (AS).
Week Four • Traffic Flow - Bidirectional and symmetric is when both ends of the flow send traffic at the same rate. - Bidirectional and asymmetric is when the client sends small queries and servers send large streams of data in return. - Broadcast flow is unidirectional and asymmetric.
Week Four Cisco NetFlow collects and measures data as it enters a router and switch interface, it’s source, and destination , IP address, source and destination TCP or UDP port numbers, packet and byte counts. The objective is to document the megabytes per second between pairs of autonomous systems, networks, hosts, and applications. Use the Network Traffic Flow on the Existing Network form (Table 4-3) to document this information.
Week Four • Characterize types of Traffic Flow for the New Network Applications 1. Terminal/host traffic flow (Telnet, asymmetric) 2. Client/server traffic flow (Thin client, bidirectional and asymmetric) 3. Peer-to-peer traffic flow (ftp, NFS, and HTTP, bidirectional and symmetric) 4. Server/server traffic flow ( implement directory services, cache heavily used data, and to mirror data, bidirectional and symmetric) 5. Distributed computing traffic flow (task manager, applications that require multiple computing nodes)
Week Four Client/Server Traffic Flow The client/server traffic flow is the most popular used flow type. The main computing device is a server that has powerful processing capabilities, manages disk storage, printers, or network resources. Clients are laptops or workstations that run user applications. The client sends a request to the server to initiate some type of action. The client relies on the server for access to resources, such as, disk storage, application software, printers, and CPU power. The communication flow between the client/server is usually bidirectional and asymmetric.
Week Four Client/Server Traffic Flow Client/server protocols Server Message Block (SMB) Network File System (NFS) Apple Filing Protocol (AFP) NetWare Core Protocol (NCP) Currently, http is the most widely used client/server protocol. Thin Client Traffic Flow The software and hardware are specifically designed to be simple. The majority of all processing is intended to be on the server. Thin client technology is also known as server-based computing.
Week Four Thin Client Traffic Flow What are the advantages of using thin client? 1. Low equipment expense 2. Low support cost 3. Centralized base of applications that are managed, configured, and upgraded only one time. 4. Reduced network manager expenses by not configuring system individually. What are the disadvantages of using thin client? 1. Starting up all computers at the same time each day can cause too much bandwidth traffic.
Week Four Thin Client Traffic Flow The communication flow with thin client technology is usually bidirectional and asymmetric. Peer-to-Peer Traffic Flow Communication entities normally transmit equal amounts of data to each other. No hierarchy exists in this type traffic flow.
Week Four Peer-to-Peer configurations represents sites having the same QoS requirements. Examples are as follows: 1. LAN environments, where laptops all laptops can access each other’s data and printers 2. FTP 3. Telnet 4. HTTP 5. NFS sessions between hosts 6. Videoconferencing 7. Training sessions Each host acts as both a client and a server. There are many traffic flows utilized with this configuration. The communication flow with Peer-to-Peer is usually bidirectional and symmetric.
Week Four Server/Server Traffic Flow Server/server traffic flow represents transmissions between servers and servers and management applications. Servers normally communicate with other servers to implement directory services, to cache frequently used data, to replicate data for load balancing, and redundancy, to back up data. Server/serve traffic flow can be structured. In some cases, the servers can be configured to a hierarchy. Distributed Computing Traffic Flow Distributed computing has applications that require multiple nodes cooperating together to complete a task.
Week Four Distributed Computing Traffic Flow With distributed computing, data travels from a task manager to computing nodes and between nodes. The communication flow with distributed computing is usually bidirectional and symmetric. Nodes that transmit information frequently are considered tightly coupled and nodes that communicate less frequently, are loosely coupled. Communication between the task manager and the computing nodes vary. The task manager can tell the computing nodes what to do frequently or infrequently.
Week Four Traffic Flow in Voice over IP Networks involves two types of flows. • Audio 1.1 Peer-to-peer traffic flow (phone to phone) 1.2 Real-Time Transport Protocol 2. Set up and tear down 2.1 Characterized as client/server traffic flow (phone needs a communicate with a more sysfisticated device, such as a server or phone switch that understands phone numbers, addresses, and has the capabilities to negotiate).
Week Four Real-Time Transport (RTP) is a connectionless protocol that runs on top of UDP. The setup, tear down, and control protocols in an IP network are as follows: • H.323 • Cisco Skinny Client Control Protocol (SCCP) • Simple Gateway Control Protocol (SGCP) • Media Gateway Control Protocol (MGCP) • Session Initiation Protocol (SIP)
Week Four Traditional Voice Networks Based on private branch exchange (PBX) VoIP Networks Use packet switching, which must handle two functions. Call control handles call setup, tear down, addressing, and routing , and informational and supplementary services. Call control handles comparing the digits dialed by the user to the configured number patterns to determine how to route a call Call switching actually handles switching the call.
Week Four • Document Traffic Flow for New and Existing Network Applications Use the Network Application Traffic Characteristics form to identify traffic flow for new and existing network applications. • Characterize Traffic Load Traffic load information can help characterize networks with sufficient capacity for local usage and internetwork flows. Estimating traffic loads is difficult. Try to avoid a design that has any bottlenecks in the network design.
Week Four • Calculate Theoretical Traffic Load The traffic load (offered load) is the sum of all the data, all network nodes that are ready to send at a particular time. The goal is to design the network capacity to be more than adequate to handle the traffic load. -The number of stations -The average time that a station is idle between sending frames. -The time required to transmit a message once medium access is gained.
Week Four • Document Application Usage Patterns - Identify user communities • Identify the applications users use • Refine Estimates of Traffic Load Caused by Applications - Revisit the size of the data objects sent by applications - The overhead caused by protocol layers, and any other load caused by application initialization.
Week Four • Traffic Overhead for the Different Protocols Preamble Header Payload • System Level Protocols Ethernet Version II Total bytes 38 IEEE 802.3 with 802.2 Total bytes 46 HDLC Total bytes 10 IP Total bytes 20 TCP Total bytes 20 UDP Total bytes 8
Week Four • System Level Protocols Address Resolution Protocol (ARP) Dynamic Host Configuration Protocol (DHCP) Internet Control Message Protocol (ICMP) Domain Name System (DNS) Multicast DNS (mDNS) NetBIOS name queries ( runs on the session layer of the OSI model) Network Time Protocol (NTP) Simple Service Discovery Protocol (SSDP) Service Location Protocol (SLP) Simple Network Management Protocol (SNMP)
Week Four The Simple Network Management Protocol (SNMP) is by far, the dominant protocol in network management. A key reason for its widespread acceptance, besides being the chief Internet standard for network management is its relative simplicity. Implementing SNMP management in a networked device is far more straightforward than most other standard or non-standard approaches to network management. Despite that, SNMP application development has not been as simple as one would like. It has required significant effort to develop management applications to manage the variety of networked devices to be managed. This situation is now changing for the better, as more SNMP tools are available. There are also different versions of SNMP available, such as SNMP V1, SNMP V2c, and SNMP V3. With improved tools, SNMP is poised to deliver end-to-end management for all areas of the growing internet industry.
Week Four SNMP management has become the dominant standardized network management scheme in use today. The SNMP set of standards provide a framework for the definition of management information along with a protocol for the exchange of that information. The SNMP model assumes the existence of managers and agents. A manager is a software module responsible for managing a part or all the configuration on behalf of the network management applications and users. An agent is a software module in a managed device responsible for maintaining local management information and delivering that information to a manager via SNMP. A management information exchange can be initiated by the manager (via polling) or by the agent (via a trap). Agents function as collection devices that gather and send data about the managed resource in response to a request from the manager. UDP ports 161 and 162 are the default ports reserved for SNMP. The agent listens for requests and replies to them over port 161 and reports asynchronous traps on port 162, unless it is instructed to use different ports. SNMP accommodates resources that do not implement the SNMP software by means of proxies. A proxy is an SNMP agent that maintains information on behalf of one or more non-SNMP devices.
Week Four • Broadcast/Multicast Traffic - A broadcast frame goes to all network stations on a LAN. Routers do not forward broadcasts. IPv6: FF:FF:FF:FF:FF:FF (128 characters) - A multicast frame goes to a subset of stations. IPv6: 01:00:0C:CC:CC:CC Cisco routers and switches running Cisco Discovery Protocol (CDP) on a LAN.