Building a Real-World Network
- Network Types
- Know the differences between all the “area network” acronyms.
- Geographical: LAN, WAN, CAN, MAN, Internet;
- Wireless: WLAN, PAN;
- Network Design
- Network design starts with assessing customer needs.
- Design considerations include documentation, compatibility with existing hardware & software.
- Bring in security early & make sure to assess external connectivity.
- Assess current networking infrastructure.
- Analyze existing network documentation.
- Assess wireless needs.
- Power Management
- UPS–Uninterruptible Power Supply
- A UPS is a battery back-up & should be used for short-term power loss.
- Power generators can be diesel or gas, and are used to maintain power for when electric power is not available.
- Dual power supplies and redundant circuitry are hardware power management and often used in critical systems.
- Unified Communications
- Unified communications combines VoIP phones, video, fax, chat, & more into a single system.
- Key components of U.C. are:
- the U.C. device;
- the U.C. server;
- and the U.C. gateway.
- Ports:
- RTP [5004, 5005(TCP)],
- SIP [5060, 5061(TCP)],
- H.323 [1720(TCP)],
- M.G.C.P. [2427, 2727(Both)]
- Unified Communication includes:
- Collaborative Tools/Workflow,
- Presence Information,
- Video Conferencing/Real Time,
- Fax,
- Messaging
- Medianet–a bunch of U.C. gateways that, using QoS techniques, make sure that our voice or our video data gets from one place to the next in a timely basis.
- RTP (Real-Time Transport Protocol)–TCP ports 5004 and 5005
- SIP (Session Initiation Protocol)–TCP ports 5060 and 5061.
- H.323–an I.T.U. protocol (International Telecommunication Unit) TCP port 1720
- MGCP (Media Gateway Control Protocol)–used for Media gateways, seen in MediaNets. ports 2427 and 2727.
- Network Documentation
- Physical documentation includes a wiring diagram of the network, drop locations, and enumeration of equipment.
- Rack diagrams specify physical location & specification of each piece of equipment in the rack.
- Logical documentation shows the VLANs, domains, and port & primary TCP/IP information.
- Inventory management
- Physical documentation vs. Logical documentation
- IDF/MDF Diagrams
- *Be familiar with Cisco icons!
- Contingency Planning
- Contingency planning attempts to mitigate adverse incidents to preserve business continuity.
- Understand the pros & cons of the offsite options available:
- Back-up sites: Cold Site, Warm Site, and Hot Site;
- Thorough planning and practice is what makes recovery plans successful when disasters occur.
- Disaster recovery–Evacuation Plan
- Cold Site:
- It takes weeks to bring back online;
- Basic office space: buildings, chairs, AC;
- No operational equipment;
- Cheapest recovery site
- Warm Site:
- It takes days to bring online;
- Operational equipment but little or no data.
- Hot Site:
- It takes hours to bring online;
- Real-time synchronization;
- Almost all data ready to go–often just a quick update;
- Very expensive!
- Distance & Location
- Internet requirements
- Housing & Entertainment
- After the event, an Order of Restoration is needed:
- Power –> Wired LAN –> ISP Link –> Active Directory/DNS/DHCP servers –> Accounting servers –> Sales & accounting workstations –> Video production servers & workstations.
- Failover
- Alternative processing sites
- After action reports–clear & detailed documentation of what happened.
- Predicting Hardware Failure
- Mission critical equipment should have a known:
- MTTF (Mean Time To Failure),
- MTTR (Mean Time To Repair),
- and MTBF (Mean Time Between Failure);
- MTBF is the MTTF + MTTR, together!
- SLA (Service Level Agreement) with a 3rd party can be used on equipment to define expected downtime and offline periods.
- For continuity, estimate expected turnaround time for parts & services if the system goes down.
- Backups
- Understand the differences between incremental & differential backups.
- Snapshots are typically used with virtual machines & are usually not stored on separate media.
- Be able to describe the pros & cons of local vs. remote vs. cloud-based backups.
- Differential Backup–a backup of all the changes since the last full backup.
- Incremental Backup–only backs up changes made from last backup.
- Local Backups vs. Offsite backups vs. Cloud backups
