• Mạng + hướng dẫn để mạng6 phiên bản• Chương 15• Quản lý mạng• Mục tiêu• Giải thích khái niệm cơ bản liên quan đến quản lý mạng• Thảo luận về tầm quan trọng của tài liệu, cơ sở đo, chính sách và quy định trong việc đánh giá và duy trì một mạng lưới sức khỏe• Quản lý một mạng lưới hiệu suất bằng cách sử dụng phần mềm quản lý SNMP dựa trên mạng lưới, Hệ thống và bản ghi sự kiện, và giao thông định hình kỹ thuật• Mục tiêu (cont 'd)• Xác định lý do và các yếu tố của một hệ thống quản lý tài sản• Lập kế hoạch và thực hiện theo thường xuyên phần cứng và phần mềm bảo trì thói quen• Nguyên tắc cơ bản của quản lý mạng• Quản lý mạng-Đánh giá, theo dõi, và duy trì tất cả các khía cạnh mạng-Phạm vi khác nhau theo kích thước và tầm quan trọng của mạng-Một số các môn học quản lý mạng-Tất cả chia sẻ cùng một mục tiêu• Nâng cao hiệu quả và hiệu suất• Ngăn chặn thời gian chết tốn kém và mất-Dự đoán vấn đề trước khi chúng xảy ra• Tài liệu• Mạng khía cạnh để tài liệu-Cấu trúc liên kết vật lý-Truy cập phương pháp-Giao thức-Thiết bị-Hệ điều hành-Ứng dụng-Cấu hình• Tài liệu (cont 'd)• Quản lý cấu hình-Bộ sưu tập, lí, đánh giá về cấu hình tài liệu• Tài liệu tất cả các khía cạnh mạng-Tiết kiệm trong tương lai công việc• Mạng sơ đồ-Đồ họa đại diện của các thiết bị mạng, kết nối-Sử dụng phổ biến Cisco biểu tượng– Provide broad snapshot of network’s physical or logical topology• Documentation (cont’d.)• Wiring schematic– Graphical representation of network’s wired infrastructure– Detailed form• Includes every wire connecting network devices– Less detailed form• Single line represents group of wires connecting several clients to a switch• Baseline Measurements• Baseline– Report of network’s current operation state• Example baseline measurements– Network backbone utilization rate– Number of users logged on per day or per hour– Number of protocols running on network– Error statistics• Runts, collisions, jabbers, giants– Frequency of application use– Bandwidth usage• Baseline Measurements (cont’d.)• Compare future and past performance– Most critical network, user functions– More data provides more accuracy• Forecasting network traffic patterns– Difficult to predict users’ habits, new technology effects, changes in resource demand• Gathering baseline data– Software applications• Freeware• Expensive, customizable hardware and software– Determine use before selecting• Policies, Procedures, and Regulations• Rules limit chaos, confusion, downtime• Sound network management policies– Media installation and management– Network addressing policies– Security-related policies– Troubleshooting procedures– Backup and disaster recovery procedures• Policies, Procedures, and Regulations (cont’d.)• State and federal regulations– CALEA (Communications Assistance for Law Enforcement Act)• Telecommunications carriers, equipment manufacturers must provide for surveillance capabilities– HIPAA (Health Insurance Portability and Accountability Act)• Protect medical records security and privacy• Many policies and procedures– Not laws– Best practices to prevent network problems• Fault and Performance Management• Assess network’s status on an ongoing basis• Performance management– Monitor links and devices’ ability to keep up with demand• Fault management– Detection and signaling of device, link, component faults• Network Management Systems• Enterprise-wide network management systems– Accomplish fault and performance management– All use similar architecture– Polling• Collecting data from multiple networked devices at regular intervals– Agent• Software routine• Collects information about device’s operation• Provides information to network management application• Network Management Software (cont’d.)• Various aspects of a device can be managed– Processor, memory, hard disk, NIC, and intangibles• MIB (Management Information Base)– Contains managed devices definition, data• SNMP (Simple Network Management Protocol)– Used to communicate managed device information– Part of TCP/IP suite– SNMPv3: most secure version of the protocol– SNMPv2 still widely used• Network Management Software (cont’d.)• Several ways to view and analyze data• Network management applications– Flexible– Challenging to configure and fine-tune– Choose correct type and amount of information to collect• Faults can trigger alarms– Also recorded in system and event logs• System and Event Logs• Log– Contains recorded conditions recognized by operating system• Event log– Windows-based computer log containing monitored device information• Event Viewer application– Application to view log information in Windows• System and Event Logs (cont’d.)• Syslog function– Standard for generating, storing, and processing messages about events on Linux or UNIX– Data written to system log• Using logs for fault management– Logs keep history– Information collected does not point to problem– Logs must be monitored for errors– Application used for viewing, filtering information• Traffic Shaping• Traffic shaping– Manipulating packet, data stream, and connection characteristics• Manage type and amount of traffic traversing network – Goals• Assure timely delivery of most important traffic• Offer best possible performance for all users• Traffic Shaping (cont’d.)• Techniques– Delay less important traffic– Increase priority of more important traffic– Traffic policing• Limit traffic volume flowing in and out of interface during specified time period• Limit momentary throughput rate for an interface• Not without controversy– Comcast discriminated against certain traffic types• Traffic Shaping (cont’d.)• Traffic prioritization– Treating more important traffic preferentially• Prioritization based on characteristics– Protocol– IP address– User group– DiffServ (Differentiated Services) flag or TOS (type of service) field in IP datagram– VLAN tag in Data Link layer frame– Service or application• Caching• Caching– Local storage of frequently needed files– Allows quick access• Web caching– Most common caching type, highly customizable– Web pages stored locally• On host or network, and then delivered to requesters• ISP cache engine– Network device devoted to storage, frequently requested file delivery– Saves money; lowers WAN traffic• Asset Management• Identifying and tracking hardware and software• First step– Inventory each network node• Organization needs– Determine appropriate asset management tool• Benefits– Simplifies maintaining and upgrading network– Provides information about hardware and software costs and benefits• Change Management• Managing change while maintaining network efficiency and availability: – Requires good planning• Common software and hardware changes– Range from installing patches to replacing network backbone
• Several ways to approach changes
• Software Changes
• Software upgrades
– Important for keeping system running optimally
• Application patches and upgrades
– Correction, improvements, and enhancements to particular software application
– Change only part of an application
• General steps
– Determine whether patch or upgrade is necessary
– Research change purpose, compatibility, and effects
– Determine whether changes should apply to all users
– Determine distribution method
• Software Changes (cont’d.)
• General steps (cont’d.)
– Notify appropriate personnel of intent to change
– Back up current system
– Prevent users from accessing system during change
– Keep instructions handy as you install revision
– Implement the change
– Test system fully
– Re-enable access to the system
• Or revert to previous version
– Inform personnel that change is complete
– Record change in the change management system
• Software Changes (cont’d.)
• NOS (Network Operating System) upgrades
– Most critical upgrade type
– Involves significant and potentially drastic changes to the way servers and clients operate
– Upgrade requires forethought, product research, and rigorous testing
– Ask and answer significant questions
– Create a project plan
– Complex, far-reaching change
– Ensure appropriate budget, resources, and time
• Software Changes (cont’d.)
• Steps in NOS upgrade
– Research
– Project plan
– Proposal
– Evaluation
– Testing
– Training
– Preimplementation
– Implementation
– Postimplementation
• Software Changes (cont’d.)
• Reversing a software upgrade
– Software change may create unexpected problems
– Be prepared to reverse an upgrade
• Backleveling
– Reverting to previous version of software after attempting upgrade
– No hard-and-fast rules for backleveling
– Always refer to software vendor’s documentation to reverse an upgrade
• For NOS: consult other professionals as well
• Hardware and Physical Plant Changes
• Required when network component fails or malfunctions
• More commonly performed as upgrade
– Increase capacity, improve performance, and add network functionality
• Face same issues as software changes
– Proper planning is key
– Follow steps on Pages 712-713 of text
• Hardware and Physical Plant Changes (cont’d.)
• Adding or upgrading equipment
– Difficulty determined by past use; experience with hardware or vendor
– Take time to research, evaluate, and test unfamiliar equipment
– Rapid hardware industry changes
• May affect consistency of installed products
– If consistency is a concern
• Purchase as much hardware as possible in single order
• Purchase from same vendor
• Hardware and Physical Plant Changes (cont’d.)
• Adding or upgrading equipment (cont’d.)
– Different preparation and implementation requirements for each device type
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