CCNA Notes: Cabling Types

Cabling Types

UTP (Unshielded Twisted pair)

Cat 1 - Telco, telephone line
Cat 2 - Token Ring, up to 4 MBPS speed
Cat 3 - 10BaseT Ethernet - 10 MBPS
Cat 4 - Token Ring, 16 MBPS
Cat 5 - Fast Ethernet, 100 MBPS
Cat5e- Fast Ethernet, 1000 MBPS (1 Gig)
Cat6 - Fast Ethernet, 1000 MBPS (1Gig), 24-gauge

UTP Ethernet cables typically use an RJ-45 adapter for connections.

Article explaining more about the UTP Ethernet cabling


Fiber Cabling

 Multi-mode Fiber - Used over shorter distances, uses LEDs to create light and bounces light signal on cladding. Cheaper than single-mode fiber. Greater speeds are attainable the shorter the distance traversed, from 100 MBPS at 2km to 10 GBPS at 550m.

Single-mode Fiber - Used over greater distances, uses laser to generate light, which is carried on a single line without bouncing. More expensive than multi-mode. Covers far greater distances based on speed and other factors, up to 60km in some cases

Fiber cables typically utilize an SFP/GBIC connector.

Comparison of Cabling Types

Cable Type             Maximum Length              Maximum Speed                 Notes

UTP                                  100m                        10 MBPS - 1 GBPS          Susceptible to interference

Coaxial                             500m                        10 - 100 MBPS                 Difficult to troubleshoot

Fiber                                 60+km                        10 MBPS - 10GBPS         Expensive


Speeds

Ethernet - 10 MBPS
Fast Ethernet - 100 MBPS
Gigabit Ethernet - 1000 MBPS

Article covering many different flavors of Gigabit Ethernet

WAN Cabling Types

 T-carrier

The following was taken from this Wikipedia article and covers a vanishing, but still present, WAN technology. Connections are typically made to routers by way of a serial cable or RJ-48 connector, and clocking for the line speed is set by the WAN provider. The standard naming convention is T-1 (or DS-1).

T-carrier and E-carrier systems	North American	Japanese	European (CEPT)
Level zero (channel data rate)	64 kbit/s (DS0)	64 kbit/s	64 kbit/s
First level	1.544 Mbit/s (DS1) (24 user channels) (T1)	1.544 Mbit/s (24 user channels)	2.048 Mbit/s (32 user channels) (E1)
(Intermediate level, T-carrier hierarchy only)	3.152 Mbit/s (DS1C) (48 Ch.)	–	–
Second level	6.312 Mbit/s (DS2) (96 Ch.) (T2)	6.312 Mbit/s (96 Ch.), or 7.786 Mbit/s (120 Ch.)	8.448 Mbit/s (128 Ch.) (E2)
Third level	44.736 Mbit/s (DS3) (672 Ch.) (T3)	32.064 Mbit/s (480 Ch.)	34.368 Mbit/s (512 Ch.) (E3)
Fourth level	274.176 Mbit/s (DS4) (4032 Ch.)	97.728 Mbit/s (1440 Ch.)	139.264 Mbit/s (2048 Ch.) (E4)
Fifth level	400.352 Mbit/s (DS5) (5760 Ch.)	565.148 Mbit/s (8192 Ch.)	565.148 Mbit/s (8192 Ch.) (E5)

Optical Carrier over SONET (Synchronous Optical Networking)

Don't be terrified by the intense wording - This is fiber. Fiber strands are bundled to reach different amounts of bandwidth, with each increment being multiplicative on the first, as follows:

OC-1 - 51.84 MBPS
OC-3 - 155.52 MBPS
OC-12 - 622.08 MPBS
OC-48 - 2488.32 MBPS
OC-192 - 9953.28 MBPS
OC-768 - 38,486.016 MBPS

Of course, multiple customers can reside on an OC, so it is common to have, for example, an OC-192 split among many different customer circuits as needed. Commonly, the largest fiber cables are bundled in the 'backbone' networks, and then multiplexers are used to divide the light signal off into smaller cables as they get nearer to customers, in some cases delivering it right to their door, where GBICS/SFPs are connected to the premise equipment. More commonly the WAN provider or local carrier will have a smartjack or some similar demarcation point, and then the customer equipment will connect to that.

Learn more about how optical carrier data is joined/split here.

CCNA Notes: The OSI Model

The OSI Model of Networking

There are easily hundreds of ways to try and explain the OSI Model of Networking to an audience. A quick Google search will net some of the best, but in general, what's important to understand about the Open Standard Interconnect model is that it breaks down host to host transmission into seven layers, listed above. The highest layer is the Application layer, where information is presented to the user. The lowest layer is the Physical layer, where the electrical/radio/light signals are transmitted along whatever medium exists between the hosts. The actual units of data are referred to by different terms beyond the Session layer, as you can see.


Note: The analogy presented below was not taken from a book, it is my own attempt to explain.

Application Layer

This layer deals with the protocols/services used by the actual applications used, which they will employ to transmit network information.

Pretend for a moment that we are in the Wild West. Sally Packett has just written a thrilling, loin-warming romance novel, and wants to send the manuscript to her publisher. At this layer of the OSI model, Sally Packett simply makes the decision to use Western Union Courier Services to get her important package to the publisher, who is anxiously awaiting the finished copy.

Presentation Layer

This layer defines how the information is to be presented to the user, file formats work at this layer, such as JPG, BMP, TXT, AVI, and so on.

Sally Packett needs to be sure that her manuscript will be readable, so she makes sure that she wrote the whole novel in English (she had a few glasses of wine for inspiration some nights). After that, she makes sure her grammar is correct and picks up her telephone.

Session Layer

This layer initiates the setup and teardown of connections, and differentiates between multiple network connections. This layer deals with hello packets, notifications, timeouts, the logistics of how data will be delivered.

Sally has a long talk with a very helpful gentleman from Western Union on the telephone, who assures her that they do deliver to the publisher's address. Sally schedules the pickup of her manuscript as soon as possible. The Western Union clerk has Sally verify how many pages there are in her book and other details about the package, as well as determining how soon it needs to get there and, depending on how much Sally wants to pay, may or may not offer a tracking number/receipt.

Transport Layer

This layer deals with the mechanics of setting up, maintaining, and tearing down connections. Transmission Control Protocol (TCP, of the famous TCP/IP suite) operates at this layer. User Datagram Protocol (UDP) also operates at this layer. The largest difference between TCP and UDP is that TCP is connection-oriented, meaning it keeps track of the data delivery attempt and will attempt to recover if it is having trouble (missed packets, corrupt data, packets arriving out of sequence). UDP is not connection-oriented. If TCP were a delivery driver, it would be the one that won't leave a package without a signature. If UDP were a delivery driver, the truck might slow down as the package was thrown at your house.

In our Wild West example, Sally Packett has elected to go with a more expensive option (after all, this romance novel will make her rich when it sells!). She receives a tracking receipt and soon afterward her manuscript is picked up by the Western Union courier. The courier goes back to the central office and informs the management that he's starting his trip to the publisher's address. The central office issues the courier the correct horse, a rifle and rations for the trip. The courier is ready to go, he has all the details of the delivery, except he doesn't know how to get there yet.

Network Layer

This layer provides the logical topology of the network, makes routing decisions to determine the best path to logical destinations, and allows logical addressing instead of otherwise obtuse physical addressing. IP addresses operate at the Network layer, saving us all from having to memorize hardware MAC addresses of source/destinations (At least for now - I'm looking at you, IPv6).

The Western Union courier (Let's call him Jim. It's easier that way) consults the map of the western territories to figure out his route. Unfortunately, the central office where he works only has a route to the next way station in line, not the entire map. He knows that the name of the way station is Tuscaloosa Valley Station, and how to get there. Jim knows what to expect, and he has all the proper tools for the journey. He leaves the office and takes the western road. Come hell or high latency, he's going to see that package delivered.

Data Link Layer

This layer uses physical hardware addressing, and defines how devices should communicate within a given physical media type. It also defines how a device accesses the network, the media's framing method and the transmission method on that media. This is the layer that uses MAC addressing to determine source/destination. This one is tough to understand, just remember that at this layer, there are no fancy IPs that are easy to read, just ugly MAC addresses.

Jim has just started his journey. Up ahead, he sees signs on the road, telling him that slower horses should stay to the right, and that stagecoaches have right of way. Jim isn't looking to run afoul of the Marshals, so he aims to pay attention to the rules of the road. He looks for a sign pointing him in the direction of the Tuscaloosa Valley Station, but he just sees signs for Alabama. Luckily, he knows from the office map that Tuscaloosa is in Alabama, and he is headed the right way.

Physical Layer

This layer deals with the physical properties of the network media. This includes connectors, multiplexers, adapters, lines, radio, light, and electrical signals. At this layer, it's raw signal, binary ones and zeroes moving across the medium. The Data link layer will determine who those signals are for and how they should be interpreted, the Physical layer's only concern is how to convey that signal.

It's been a long, hard road. Jim is parched, hungry, and has dodged his share of bullets from unfriendly natives and bandits alike. Only his wits and the speed of his horse saved him, as well as the fine condition of the road.

Now What?

Jim has arrived in Alabama alive and with Sally Packett's manuscript intact. Once in town, he gets directions from a friendly local to the Tuscaloosa Valley Station. At the station, two possibilities exist for Sally's package.

• If Tuscaloosa is indeed the final destination, Jim will turn over the package to the publisher, who will open it and verify everything arrived in order, then format it and prepare it for sale, moving up from the Network layer to the Application layer in sequence.
• If there are further legs of the journey, his trip will begin again, picking up from the Network layer back down to the Physical in a process called encapsulation/de-encapsulation until the final destination is reached.

 

Book Citations for Study Notes

CCDA Study Notes

Official Cert Guide: CCDA 640-864

Authors: Anthony Bruno and Steve Jordan

ISBN-13: 978-1-58714-257-4

Buy it on Amazon!

 

CCNA Study Notes

Cisco Certified Network Associate Study Guide

Author: Richard Deal

ISBN-13: 978-0-07-149730-5

Buy it on Amazon!

CCNA Voice Study Notes

Official Certification Guide: CCNA Voice 640-461

Authors: Jeremy Cioara and Michael Valentine

ISBN-13: 978-1-58720-417-3

Buy it on Amazon!

CCDA Notes: Network Design Methodology

Network Design Basics

Business forces that affect decisions for enterprise network include:

• Return on Investment - Cost savings or increased productivity
• Regulation - Meet industry regulations (HIPAA, DOD, etc)
• Competitiveness - Technology needs to make business more competitive

Technology forces which affect decisions for network include:

• Removal of borders - Network resources must be accessible from more places than before, like branch offices, teleworkers, mobile devices and business partners
• Virtualization - Reduction in hardware/power/software needs as well as space considerations by virtualizing many services
• Growth of Applications - As applications become larger and more demanding of resources, network resources are required to adapt

IT optimization areas can be split into three groups:

1. Data Centers
2. Networks
3. Applications

Three architectures provide for optimization within each group and inter-group as well:

• Borderless Networks Architecture
• Collaboration Architecture
• Data Center/Virtualization Architecture

Borderless Networks Architecture

1. Policy/Control: Policies applied across all users/devices
2. Network Services: Resiliency and control
3. User Services: Services include performance, mobility, security
4. Connection Management: Delivers secure access anytime/anywhere

Collaboration Architecture

1. Communication/Collaboration Apps: conferencing, messaging, mobile apps, IP comms, social software
2. Collaboration Services: Services that supports the collaboration apps: policy/security management, contact management, session management, location, presence, client framework
3. Infrastructure: Allows collaboration anytime/anywhere on any device. This layer includes virtual machines, the network and storage.

Data Center/Virtualization

Data center/virtualization architecture is built on Cisco Data Center 3.0, which has a set of virtualization technologies/services that bring network/storage/computing/virtual platforms together

PPDIOO: The Cisco Lifecycle

• Lowers cost of ownership by validating tech requirements, planning for infrastructure changes/resource requirements
• Increases network availability through good network design
• Improves business by establishing technology strategies/business requirements
• Speeds access to applications through improved availability, reliability, scalability, security and performance

Lowering Cost Of Ownership:

• Identify/validate tech requirements
• Plan for infrastructure changes/resource requirements
• Develop network design to mesh with business/technology needs
• Improve network efficiency
• Reduce operating expense by streamlining processes/tools

Increasing Network Availability

• Assess the network and its ability to support design
• Choose correct hardware/software and keep current
• Create good network design and verify operation
• Staging/testing before implementation
• Improving engineer skills
• Proactively monitor network for issues
• Proactively identify security issues and remediation plan

Improve Business

• Establish business/technology requirements
• Ready sites to support design
• Integrate technical needs and business needs into design
• Expertly install system components
• Continue to enhance performance after implementation

Speed Application Access

• Improve operational readiness for current/planned network technology/service
• Increase availability, capacity and performance of network
• Manage/resolve issues affecting system, keep software current

 PPDIOO Phases:

Prepare Phase

Establish requirements, develop network strategy, propose high-level network architecture

 

Plan Phase

Identify requirements by assessing current network and perform gap analysis between current/proposed

 

Design Phase

Provide high availability, scalability, reliability, security and performance in design

 

Implement Phase

Install/configure new equipment

Operate Phase

Analyze daily network operations and operational health

 

Optimize Phase

Proactive network management, propose modifications to design as needed

 

Design Methodology

1. Identify Customer Requirements

Identify network apps/services

• Planned Applications
• Concrete applications
• Importance to business
• Other Info/Comments

Define goals of organization, such as:

• Increase competitiveness in field
• Reduce costs
• Improve customer relations (Better support, new services)

Identify possible constraints

• Budget
• Timeframe
• Limited personnel
• Policy limitation

Define technical goals

• Improve network speed
• Decrease failures
• Simply management of network
• Improve security
• Improve scalability
• Improve reliability
• Tech refresh

Identify possible technical constraints

• Legacy applications
• Bandwidth allocation may not meet application needs
• Existing infrastructure
• Legacy equipment

 

2. Assess Current Network

• Identify/Gather existing documentation about organization/network
• Audit network to determine details of network
• Analyze traffic for applications/protocols used

Identify/Gather Documentation

Include site designs, contacts, hours of operation/access and addresses, where network equipment is located and what infrastructure exists. Also gather info about LAN/WAN wiring and contact info for WAN providers. Especially look for IP/Vlan schema and IP allocation information, as well as network applications and servers in use

Network Audit

Use existing documentation, existing network management tools, and new tools to covers gaps in analysis. Audit should provide following:

•  List/naming convention for network devices
• Hardware info for network devices
• Software versions for network info as well as supported applications
• Network configs
• LAN/WAN speeds of vital links
• Auditing tool output
• WAN technology/provider info

Manual Analysis: review device configs, manually use show commands and collect output

• show tech-support
• show version
• show log
• show running-config
• show process cpu
• show process memory
• show interface

Network Analysis Tools: Inspects packets for data flow/traffic analysis

• Netform DesignXpert Enterprise: Desktop tool to discover/design/quote/propose solutions
• CNS NetFlow Collector: Cisco hardware that collects network info
• Cisco Embeded Resource Manager: Monitors IOS processes/utilization
• Third-party tools: SolarWinds, NeTMRI, etc

After audit, check to make sure the following is true before moving on with design:

• Network segments should be switched, not using hubs
• WAN links are not saturated (70% or higher)
• Response time acceptable (Generally 2ms on LAN, less than 100ms on WAN)
• No segemts have more than 20% multi/broadcast traffic
• No segment has more than 1 CRC per MB of data
• Less than .1% of packets collide on ethernet segments
• Network devices shouldn't have 75% CPU utilization for 5 min or over
• Interface output drops shouldn't exceed 100 per hour
• Interface input queue drops shouldn't exceed 50 per hour
• Interface buffer misses shouldn't exceed 25 per hour
• Interface ignored packets shouldn't exceed 10 per hour
• QoS should be enabled for prioritization

3. Designing Network and Solutions

Top-Down

Start from top layer of OSI model and work downward, adapt infrastructure for application requirements. Analyze application requirements for top layers (Application, Preentation, Session) and develop infrastructure to support it for bottom layers (Transport, Network, Data Link, Physical)

Benefit:

• Design meets current/future needs and organization requirement

Drawback:

• Far more time-consuming

Bottom-Up

Start from bottom of OSI model and build upward. Utilize best practice and previous implementation experience to design network without taking specific application requirements into account

Benefit:

• Allows for quick solution, based on best practice/previous experience

Drawback:

• May be inappropriate design, may not meet specific requirements

Develop Design Document

• Introduction: Describe project's purpose and reasoning
• Design Requirement: List requirements, constraints and goals
• Existing Network Infrastructure: Include logical topology diagram, audit results, summary list of appications, etc
• Design: Specific design info, logical/physical topology, IP/Vlan Schema, routing protocols, security, etc
• Proof of Concept: Results from prototype/pilot testing
• Implementation Plan: Detailed steps for network staff to implement design
• Appendixes: List of network devices, configs, additional info

Implementation Plan should include several phases with each phase containing:

• Description of phase
• Reference to design
• Detailed implementation guidelines
• Detailed rollback guidelines if implementation fails
• Estimated time to implement

CCNA Notes: Network Considerations and Topology/Media

Network Considerations

When designing a network, there are many factors at play. Some factors to consider:

1. Cost - What is an acceptable budget?
2. Speed - What is an acceptable speed?
3. Security - How much security is needed?
4. Topology - Where are the users? The services? What infrastructure separates them?
5. Scalability - Is this network capable of growing larger easily?
6. Reliability - Are the network solutions we are using reliable?
7. Availability - Do we have redundancy for connectivity/services?

There are different types of network locations that will help drive these questions/answers:

Small Office / Home Office (SOHO) - Small site that may or may not connect to a larger network

Central Office - Where most users/services are homed

Branch Office - An office which is geographically separated from central office but uses its services

Mobile Office - Users that connect via VPN or RAS to services, not physically connected to the network

When dealing with expectations of network speed/latency, determine whether you are talking about a LAN (Local Area Network) or WAN (Wide Area Network). LANs connect geographically close users together over high-speed links. WANs connect users over large geographical areas, as in the Central/Branch office setup, typically using much slower links.

LAN Topologies and Media

10Base5 and 10Base2 - Thicknet and thinnet coax.  This is obsolete technology and you are not likely to see it in use today. Connectivity was achieved via a vampire tap that literally tapped into the line to get signal, or the connection was terminated via BNC connector. This media was very prone to electrical interference as the cables had to have ground terminators, and was made largely obsolete by the advent of ethernet Cat5 cabling. Thicknet and thinnet were very prone to network collisions, which is what happens when two or more devices try to send signals across the wire at the same time, ruining the transmission. Later implementations of thinnet used a token ring to resolve this issue.  Token ring is a topology where collisions are avoided by having one networked device at a time utilize a logical 'token', and only the device with the token is allowed to transmit. This token was passed to other devices in turn, but this resulted in much slower speeds and ultimately token ring could not compete with ethernet collision detection/avoidance techniques.

More info on Thicknet (including pictures)
More info on Thinnet (including pictures)


10BaseT Ethernet - Category 5 (and later 6, 6e) cabling defines this standard. This is the most popular medium in use for LANs today. Most ethernet networks utilize a star, or hub and spoke topology where devices connect to network devices that aggregate connections. Network collisions are handled by CSMA/CD (carrier sense multiple access / collision detection), where when two devices detect a collision, both send a jam signal to the wire and then wait a random backoff interval before trying again.

More info on Cat5 Ethernet (including pictures)


Wireless (802.11a/b/g/n) - Radio waves comprise the physical 'media' in a wireless network. There are many different wireless standards, the differences mainly involving what channels on which the standards communicate and the speeds attainable. The topology in a wireless network is a star/hub and spoke with the wireless access point being the aggregating network device. Collision avoidance is accomplished by CSMA/CA (carrier sense multiple access / collision avoidance). Because users can communicate with the access point but not see each other's transmissions, the AP uses a system of RTS/CTS (Request to Send/Clear to Send) messages to grant exclusive transmitting capability to one device at a time, similar to a token ring.

More info on wireless standards


Fiber - Fiberoptic cables define this media type. There are enough types of fiber cabling to warrant its own entry, but in general, the signal is either carried in a single line, or there will be two lines, one dedicated to transmit signals and the other to receive them.



 FDDI - A dual fiber loop which utilized a proprietary token bus standard instead of the more prevalent token ring standard. The second fiber ring provided redundancy, but as faster ethernet standards were developed this technology was outclassed both in ease of use and price.


More info on FDDI

For the purposes of the CCNA, be aware of most different topologies and media, but focus on Ethernet and star/hub and spoke topologies.

CCNA\CCDA Notes

While studying to get my CCNA, and start my new career in Networking, I took a notebook's worth of notes. I have never once, after getting the cert, reviewed them. Two years down the road, I've decided it's time to review them for accuracy/understanding, and then transcribe them here. This will help me index them faster, and it may help some other people who are just getting into networking to study too. Who knows. I'll tag those entries appropriately, so that they can be searched/indexed easily.

First Music, Now TV

I don't pay for cable. It's too much money for too much content masking too little content in which I am interested.

I have been saying for a long time that what could make me buy cable again would be an a la carte offering, of channels and/or shows. Every time it's suggested, the cable providers have vociferously defended the current model, painting a dark future in which each person would pay a hoard of gold and gems for each channel/show because breaking the 'package' would cause costs to skyrocket.

To be honest, it smacks of the RIAA telling us about how important the model of CD sales was to the music industry. If the RIAA taught us all anything, it's that no business entity whose sole purpose for existing is to protect it's preferred business model can be trusted to deliver the facts.

Which leads me here:

Intel Jumps Into the Content Pool

Not sure why Intel is throwing its hat in the ring, but I am excited about the possibility of subscribing to particular content. Netflix and Hulu offer plenty of content at a low price, but their business model isn't the same as what Intel is aiming to accomplish. The real danger to this new emerging business model is that content providers have to be on board, and not spread their stuff around like this were the McDonalds Monopoly game or something. I don't want to have a separate subscription to Netflix, Hulu, Apple TV, Amazon Prime, HBO Go, etc. Give me my content from as few providers as possible, but give me exactly what I want. Until then, I'll make do with DVDs and streaming media.