Lectures on LAN Switching - Part 11

VLAN Trunk Protocol (VTP)

Before we go any further, let's discuss a feature that will help us manage VLANs in an ever expanding LAN network - VLAN Trunk Protocol, or simply, VTP.

This is one of my favorite interview questions before when I'm still conducting applicant interviews. Most will answer that it has something to do with Trunk configuration and management, rather than with VLANs. But that's just until they get smarter. =P

Moving forward, just imagine configuring and managing a new network with around 100 Catalyst Switches. To complicate the configuration a bit, every Switch needs to be configured with 100 VLANs. Imagine doing that repetitively on all 100 Switches. Hard right? =)

Isn't it more productive if I can just automatically replicate any VLAN configuration I make on one Switch to the other 99 Switches? Well, that's the main beauty of VLAN Trunk Protocol. VTP minimizes the administration overhead in Switches, particularly in configuring and managing VLANs across a Switched network.

You just need to configure at least one Switch as a VTP server, and the VLANs present on a VLAN Database will be replicated through all other Switches in the same VTP Domain. This will significantly reduce the time spent configuring VLANs on all your Switches. One downside though, VTP is a Cisco-proprietary protocol. You can only expect in on Cisco Catalyst Switches, and not anywhere else.

You may ask what the 'Trunk' in VTP is all about if this is only about VLAN management. Apparently, VTP will only work through Trunk connections. Any links that is only passing traffic from a single VLAN won't be able to pass through VTP advertisements.

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Lectures on LAN Switching - Part 10

Other Port Types: L3 port and SVI

We've already discussed Access and Trunk ports since they're the commonly used port types for Switches' physical interfaces (or ports). As our next topic, we're going to discuss a bit about Layer-3 (L3) ports, as well as Switch Virtual Interfaces (SVI) or more commonly known as VLAN Interfaces. These port types are generally available on Switches with routing or Layer-3 capabilities, such as:

• Catalyst 3550
  
• Catalyst 3560
  
• Catalyst 3750
  
• and most Modular Catalyst Switches

Layer-3 (L3) Port Type

L3 ports are basically routed ports. Meaning, these are previously "switched" ports that are configured to be similar to router ports. You'll want to connect this type of port to a router or to another routed port.

One main difference with real router ports is that L3 ports in Switches are not capable of having sub-interfaces.

Here's a sample configuration in creating an L3 port:

Switch#config terminal
Switch(config)#int fa0/1
Switch(config-if)# no switchport
Switch(config-if)# ip address 192.168.0.1 255.255.255.0
Switch(config-if)# no shut

You'll notice that the main configuration command is 'no switchport'. This is like literally saying to the port to stop being a "switched" port, and become the opposite (which is to be a "routed" port). The IP address configuration is just one of the most common configuration you'll do in a router port. Lastly, you need to issue a 'no shutdown' command to enable the port since all L3 ports are disabled by default.


Switch Virtual Interface

Switch Virtual Interfaces, or SVIs, are logical interfaces on a Layer-3 capable Switches. These serve as the gateway for the VLANs (or VLAN segments) to communicate with other VLANs. In a way, an SVI is similar to a router port wherein the router port leads to a network segment.

In its most basic function, you configure an IP address to the SVI to serve as the gateway IP address of a VLAN/network segment. Meaning, all PCs connected on ports that belong to a specific VLAN, will use the IP address of the corresponding SVI as their own gateway IP address. Moreover, configuring an IP address to an SVI enables PCs on a VLAN segment to communicate with other PCs on other VLAN segments (with configured IP addresses).

You also need to be careful in referencing SVIs. Since the more common term for SVI is Interface VLAN, a lot of people thought that this also refer to the VLAN itself. To be clear, VLAN is the network segment, while SVI (or Interface VLAN) is the gateway (much like a router interface).

Here's a sample configuration in creating an SVI:

Switch#config terminal
Switch(config)#int vlan 10
Switch(config-if)# ip address 192.168.0.1 255.255.255.0

Simple eh? =) Doing an 'interface vlan 10' effectively creates the logical SVI. To reiterate, putting an IP address effectively opens the "gate" to other VLANs for what we call "InterVLAN routing". Lastly, the IP address also serves as the telnet IP address of the Switch for any PC (on the same VLAN as the VLAN interface) who wishes to access the Switch. Read more!

IT-Related Inventions from Time's 50 Best Inventions of 2008

This morning, I'm reading Time's article on what they consider as 50 Best Inventions of 2008. There's around seven inventions, I think, that can be considered IT-related (especially in the field of communications).

And now, here's the list:

9. The Orbital Internet

In space, no one can hear you scream. But you will be able to send e-mail, thanks to a new protocol being developed for use there. It's hard to maintain a stable connection in orbit, so the interplanetary Internet will have to be especially tolerant of delays and disruptions. In September, a satellite used the new protocol to relay an image of the Cape of Good Hope back to Earth.

10. The World's Fastest Computer

On May 26, at 3:30 in the morning, a $133 million supercomputer nicknamed Roadrunner broke the long-sought-after petaflop barrier: 1 quadrillion calculations per second. Built by IBM for Los Alamos National Laboratory, Roadrunner will be used primarily to simulate the effects of aging on nuclear weapons. Next up: the exaflop barrier.

13. The Memristor

Scientists have known it was possible for 37 years, but it took them that long to actually make a memristor, a new kind of circuit that remembers its history even when turned off. One possible application: a computer that flicks on instantly, like a lightbulb, with no boot-up required.

19. Montreal's Public Bike System

When lots of people use a communal resource — like, say, a cheap public bicycle-rental program — they tend to abuse it. So when the city of Montreal built its Public Bike System, nicknamed Bixi, the designers packed in all the technology they could find, in a desperate attempt to out-engineer human iniquity. The modular bike-rack stations are Web-enabled and solar-powered. The bicycles are designed with tons of sealed components to resist the savage beatings they will undoubtedly receive, and they're equipped with RFID tags so they're easily trackable. Too bad they can't redesign the riders too.

24. Bionic Contacts

The University of Washington's Babak Parviz has created a prototype "bionic" contact lens that creates a display over the wearer's visual field, so images, maps, data, etc., appear to float in midair. The lens works using tiny LEDs, which are powered by solar cells, and a radio-frequency receiver.

30. The Internet Of Things

In September, a group of high-tech companies that includes Cisco and Sun formed the IP for Smart Objects Alliance. Simply put, the organization intends to create a new kind of network that will allow sensor-enabled physical objects — appliances in your home, products in a factory, cars in a city — to talk to one another, the same way people communicate over the Internet.

47. Google's Floating Data Center

The hidden cost of the triumph of the Internet is the rise of the data center. The Net runs on huge complexes of hot, power-hungry servers that eat up real estate and energy in massive quantities — in 2006 data centers consumed a staggering 1.5% of the U.S.'s entire supply of electricity. Engineers at Google may have found a way out: the self-sufficient floating data center. According to a patent filed by Google, wind turbines and wave-powered generators will provide the electricity. Ocean water will cool the servers, which throw off huge amounts of heat. And offshore real estate is essentially free.

If you're wondering why I included Montreal's Public Bike System and Bionic Contacts, well, that's because of the use of radio-frequency communications (like RFID). And for last, I think the weirdest investion on the list is the New Ping Pong Serve which comes at number 36. Wow! =) Read more!

Cisco Books for CCDA and CCDP Certifications

Right now, I've been reading, or maybe just browsing, these books for my CCDA certification goal:

CCDA Official Exam Certification Guide, Third Edition

By Anthony Bruno; Steve Jordan

Book Chapters

• Chapter 1. Network Fundamentals Review
  
• Chapter 2. Applying a Methodology to Network Design
  
• Chapter 3. Structuring and Modularizing the Network
  
• Chapter 4. Designing Basic Campus and Data Center Networks
  
• Chapter 5. Designing Remote Connectivity
  
• Chapter 6. Designing IP Addressing in the Network
  
• Chapter 7. Selecting Routing Protocols for the Network
  
• Chapter 8. Voice Network Design Considerations
  
• Chapter 9. Wireless Network Design Considerations
  
• Chapter 10. Evaluating Security Solutions for the Network
  
• Appendix A. Answers to Review Questions and Case Studies
  
• Appendix B. IPv4 Supplement
  
• Appendix C. Open System Interconnection (OSI) Reference Model
  
• Appendix D. Network Address Translation
  

Authorized Self-Study Guide Designing for Cisco Internetwork Solutions (DESGN), Second Edition

By Diane Teare

Book Chapters

• Part I: General Network Design
  
•   Chapter 1. Network Design Methodology
  
•   Chapter 2. Network Structure Models

• Part II: LAN and WAN Design
  
•   Chapter 3. Enterprise LAN Design
  
•   Chapter 4. Wireless LAN Design
  
•   Chapter 5. WAN Technologies
  
•   Chapter 6. WAN Design

• Part III: The Internet Protocol and Routing Protocols
  
•   Chapter 8. Internet Protocol Version 6
  
•   Chapter 9. Routing Protocol Selection Criteria
  
•   Chapter 10. RIP and EIGRP Characteristics and Design
  
•   Chapter 11. OSPF and IS-IS
  
•   Chapter 12. Border Gateway Protocol, Route Manipulation, and IP Multicast

• Part IV: Security, Convergence, and Network Management
  
•   Chapter 13. Security Management
  
•   Chapter 14. Security Technologies and Design
  
•   Chapter 15. Traditional Voice Architectures and IP Telephony Design
  
•   Chapter 16. Network Management Protocols

• Part V: Comprehensive Scenarios
  
•   Chapter 17. Comprehensive Scenarios

• Part VI: Appendixes
  
•   Appendix A. Answers to Chapter "Do I Know This Already?" Quizzes and Q&A Sections
  
•   Appendix B. The OSI Reference Model, TCP/IP Architecture, and Numeric Conversion

I actually like to read from last chapter and then going back. This prevents me from getting bored, and to absorb much of the information contained on these books. Weird huh? =)

As for CCDP that I'm planning to take afterwards, I'm still waiting for the updated version of this book:

CCDP Self-Study: Designing Cisco Network Architectures (ARCH)

By Keith Hutton; Amir Ranjbar

Book Chapters

• Chapter 1. Introducing Cisco Network Service Architectures
  
• Chapter 2. Designing Enterprise Campus Networks
  
• Chapter 3. Designing Enterprise Edge Connectivity
  
• Chapter 4. Designing Network Management Services
  
• Chapter 5. Designing High-Availability Services
  
• Chapter 6. Designing Security Services
  
• Chapter 7. Designing QoS
  
• Chapter 8. Designing IP Multicast Services
  
• Chapter 9. Designing Virtual Private Networks
  
• Chapter 10. Designing Enterprise Wireless Networks
  
• Chapter 11. Designing IP Telephony Solutions
  
• Chapter 12. Designing Content Networking Solutions
  
• Chapter 13. Designing Storage Networking Solutions
  
• Appendix A: Answers to Review Questions

I hope that I'll be able to accomplish these certifications before the end of the year. Wish me luck!

For more Cisco books, you can visit Amazon Bookswebsite.

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