Tag Archives: routing

Coming Soon! CCIE R&S Personal Coaching

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Overview

Success in the CCIE Written and Lab exams is difficult. In fact, many regard it as impossible. For such a challenging pursuit, many students need coaching, encouragement, and daily challenges to keep them going. AJSnetworking.com is thrilled to offer such a service.

CCIE

Personal Coaching – CCIE Routing & Switching

AJSnetworking.com is proud to announce the upcoming addition of Personal Coaching for the CCIE R&S written and lab exams.

This members-only service starts at an Introductory price of $9.95 per month. Initial subscribers receive a lifetime price lock.

Members-only services include:

  • Daily, never before seen content (quizzes, posts, checklists, videos, lab task challenges)
  • The latest news (and even rumors) surrounding the CCIE R&S exams and material
  • Valuable, downloadable resources including study tools and software
  • Live, recorded meeting sessions
  • Checkpoint assessments to validate readiness in exam areas
  • Members-only forum access
  • Private email access to our coaches
  • Special offers from AJSnetworking.com partners

Perfect For:

  • CCNP students considering CCIE
  • Learners currently pursuing CCIE Written or Lab certification
  • Current CCIE holders that want to remain current and ready for recertification
  • Network engineers needing to stay up to date with their knowledge of Routing and Switching

Tired of promises regarding CCIE preparation with no delivery? This membership is for you!

Current Coverage Areas

This membership focuses on the current topic domains of the latest written and lab exams and includes:

.5 Written Exam Strategies

.75 Lab Exam Strategies 

1.0 Network Principles 

2.0 Layer 2 Technologies

3.0 Layer 3 Technologies

4.0 VPN Technologies

5.0 Infrastructure Security 

6.0 Infrastructure Services 

7.0 Evolving Technologies 

Other Personal Coaching Services

If you are interested in a Personal Coaching service for another certification area, let us know in the comments section below this post!

An Overview of Intermediate System to Intermediate System (IS-IS)

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Intermediate System

Introducing IS-IS

Poor Intermediate System to Intermediate System (IS-IS). Open Shortest Path First (OSPF) gets all the love, and this competing Interior Gateway Protocol (IGP) is often little understood by engineers in networks today. This post will solve that for many of you, or perhaps act as a refresher if it has been a long time since you have thought about this impressive protocol.

It is not all bad news for IS-IS by the way. Part of a recent resurgence of interest has been caused by it being used as the basis for some other exciting technologies. The best example of this is Transparent Interconnection of Lots of Links (TRILL) or as Cisco calls their version, FabricPath. This layer 2 technology serves as a replacement for Spanning Tree Protocol (STP) and features the use of IS-IS as its intelligence for things like path selection and convergence. Users of TRILL are shielded from IS-IS configuration, but certainly an understanding of the protocol aids in troubleshooting and a deeper understanding.

IS-IS versus OSPF

There was a battle royal for market share when it came to the wonderful world of Interior Gateway Protocols. There were plenty that thought OSPF should rule, while others thought IS-IS. As you know, OSPF really won the battle, but it is interesting to note that many large service providers still use IS-IS today in their internal networks. Those that still love it point to how easy it can be to design and tune large networks with it.

As this post will examine in a moment, there are probably many more similarities between OSPF and IS-IS than there are differences. In fact, both use the same Dijkstra’s Shortest Path First algorithm in order to calculate best paths!

Perhaps the most shocking detail of IS-IS is the fact that it was not even developed for the routing of Internet Protocol (IP) traffic! The International Organization for Standardization (ISO) developed IS-IS for the routing of their own Connectionless Network Protocol (CLNP). In fact, at the time, many thought that IP and OSPF would be short interim solutions with CLNP and IS-IS taking over long term. Of course, IP won out, and IS-IS was quickly and easily tweaked in order to function perfectly with IP.

Integrated IS-IS

This new and improved version of IS-IS that we use today is officially referred to as Integrated IS-IS. Some use the less formal dual IS-IS when describing it. No matter what you call it – it does rock. You create your autonomous system of intermediate systems (routers) to connect end systems (workstations) that are sending and receiving packets. You typically divide your AS into smaller groups called areas. The area structure is more flexible than OSPF. You have Level 1 routers that route within an area and Level 2 systems that route between areas. If you need a device to fulfil both functions (think and ABR in OSPF), then you have what is called a Level 1/2 router.

IS-IS and OSPF

So you think the two competing IGPs might be similar? They are – just check this out:

  • Both maintain link state databases in order to function
  • Both use the Dijkstra’s Shortest Path First algorithm
  • Both use Hello packets to establish and maintain adjacencies
  • Both use a two level hierarchy
  • Both provide for address summarization between areas
  • Both use the concept of a designated router
  • Both are typically implemented with authentication in order to add security

Are you fired up to learn more about IS-IS? I hope so. I am releasing a new course this month at CBT Nuggets that will teach you even more!

Study with my passion my friends!