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Submarine Cable Basics

Submarine Cable is probably the most important topic for the International traffic. More than 99% of the International traffic , including data, voice and video is carried over Submarine Cables.

 

But still submarine cables is not very well known topic among the network engineers, especially if you are not working in the Service Provider, Carrier or Telco.  Read more

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What is Urban and Rural area in networking ?

What is urban and rural area ? What is underserved area in networking ?

 

These definitions are heavily used in networking. And all broadband network designers take always these definitions into an account while they do their design. I think knowing these definitions as a network engineer is valuable for you.  Read more

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Some recommendations for the network engineers

In this post, I will share many network engineering blogs which will be very beneficial for the network engineering and for those who want to learn more about network design.

 

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Tier 1, Tier 2 and Tier 3 Service Providers

Tier 1,Tier 2 and Tier 3 Service Providers

What is tier in the first place ? If you are dealing with Service Provider networks, you hear this term a lot. But how we define Tier 1,Tier 2 and Tier 3 Service Providers ?

What should be their infrastructure to be seen as Tier 1 for example ?

Which tier is bigger in scale ? Which one is better for the customers to purchase a service from ?

Why Service Providers claim that they are Tier 1 or Tier 2 ?  Read more

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Is Fate Sharing bad thing in network design ?

Is fate sharing bad thing in network design? Someone asked this question recently on my youtube channel and I want to share a post for the website followers as well.

First of all, what is fate sharing ? Below is the Wikipedia definition of fate sharing.

” Fate-sharing is an engineering design philosophy where related parts of a system are yoked together, so that they either fail together or not at all ” Read more

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Introduction to VPN (Virtual Private Network)

Introduction to VPN (Virtual Private Network)

Let’s start with the definition. VPN is a logical network and created over shared physical infrastructure.

Shared infrastructure can be private such as MPLS VPN of a Service Provider or over the Public infrastructure such as Internet.

There are many concepts to understand VPN in detail but in this article I will cover the definition, common design considerations, and some not well known concepts about it.

We can group VPNs into two categories. WAN and the Datacenter VPN Technologies.

WAN VPN Technologies

1.GRE

2.mGRE (Multipoint GRE)

3. IPSEC

4. DMVPN

5.GETVPN

6.L2TPV3

7.LISP

8. MPLS L3 VPN Read more

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Design considerations for network mergers and acquisitions

Network mergers and acquisitions are the processes which can be seen in any type of businesses. As a network designers, our job to identify the business requirements of both existing networks and the merged network and finding best possible technical solutions for the business.

There are many different areas which need to be analyzed carefully. Wrong business requirement gathering and design analyze, definitely lead to catastrophic failures.

Business and network analysis and technical information gathering are the key steps and there are many questions which need to be asked and answered should be well understood.

Network mergers and acquisitions is also called as Network integration.

Below are the key points for any type of network mergers and acquisitions projects.

  • Business analysis and information gathering

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OSPF Multi-Area Adjacency | OSPF Area Placement | RFC 5185

OSPFv2 by default setup only one adjacency over a single link. But this can be an issue some time and as a network designer you should understand the consequences and know the available solutions.

Placing a link in wrong OSPF area can create an OSPF sub optimal routing especially in hub and spoke topology.

In IS-IS or OSPFv3, this wouldn’t be an issue because IS-IS and OSPFv3 allow link to be placed in more than area or level. (In IS-IS, area is assigned to the router, not to the link. Thus I use level keyword)

Let’s look at the below network to understand what is the issue and how OSPF multi-area adjacency can solve the sub optimal routing problem. Read more

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IS-IS Design considerations on MPLS backbone

IS-IS Design considerations on MPLS backbone

Using IS-IS with MPLS require some important design considerations. IS-IS as a scalable link state routing protocol has been used in the Service Provider networks for decades.

In fact, eight of the largest nine Service Providers use IS-IS routing protocol on their network as of today. Read more

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BGP Peering – Private, Public, Bilateral and Multilateral Peering

BGP Peering

BGP Peering is an agreement between different Service Providers. It is an EBGP neighborship between different Service Providers to send BGP traffic between them without paying upstream Service Provider.

 

To understand BGP peering, first we must understand how networks are connected to each other on the Internet. The Internet is a collection of many individual networks, which interconnect with each other under the common goal of ensuring global reachability between any two points.

 

BGP peering
BGP Peering and Transit Links

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What is reliability in networking ?

What is reliability in networking ? Why reliability is an important design tool ? I will provide the answers of these questions with the examples in this post.

Reliability is within the reasonable amount of time, which depends on the application type and architecture, delivering the legitimate packets from source to destination.

This time is known as delay or latency and it is one of the packet delivery parameters. Consistency of delay known as jitter and it is very important for some type of applications such as voice and video, jitter is our second delivery parameters.

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BGP Next-Hop Behaviour in IP and MPLS Networks

One of my CCDE bootcamp students asked a question about next hop in MPLS VPN network. So, I would be very pleased to explain the BGP next hop behaviour both in IP and MPLS network in this post.

Let’s start with this IP network shown below (Figure-1).

IBGP next-hop

Figure-1 IBGP Next Hop handling in IP networks

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How fast is your network?

You always wonder how fast is your network, right? How long does it take the information travel over the network?

I will share with you this special article, which you can use to find the speed of your network and define it with a numerical number.

I will use ring, partial mesh and full-mesh physical topologies to explain the concept.

Note : I assume bandwidth of all the links in the examples are the same for simplicity.

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Pim Sparse Mode

Pim sparse mode – Multicast is used to send the data to the multiple receivers at the same time. Multicast reduces the load on the servers (Senders/Source in multicast term), provides efficient capacity usage on the network links.

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MPLS Design Case Study

MPLS Design – MPLS Design Case Studies are the useful resources to learn the design details of MPLS.

You will be provided a brief information about the business and technical requirements. You can share your answer at the comment section below.

Note: This is only one of the case studies in the DesignWorld.

DesignWorld provides video and written content for the network designers.

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EIGRP vs OSPF

EIGRP vs OSPF  – Below comparison table is your primary resource for the OSPF and EIGRP routing protocols when you compare them from the design point of view.

Knowing and understanding these design practices will not only help you for the real life network design but also will help for the any design certification exams.

If you have any question regarding the parameters in the comparison chart, please share in the comment so I can provide more information.

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MANET: Mobile Ad Hoc Networks

The MANET stands for mobile ad hoc network; in practice, the term generally applies to ad hoc wireless networks of sufficient complexity that some internal routing mechanism is needed to enable full connectivity.

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Single Vs. Dual Carrier Design

Companies don’t always have high availability. What’s more, there is always a concern of budget and complexity with the high availability even though a number of factors need to be considered during network design.

If the applications of the company do not require high availability, dual carrier or two links to the same carrier is not necessary.

Multihoming refers to a connection to the two different carriers/service providers even though two routers via two links to the same provider is not considered multihomed.

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IS-IS Suboptimal Routing Design

If you design multi level IS-IS network and if you have more than one exit (L1-L2 routers) from the Level 1 domain, you will likely create a suboptimal routing. Multi-level IS-IS design is for large-scale network. What’s more, most of the real life networks use only flat Level 2 IS-IS as their interior gateway protocol (IGP).

 

is-is routing protocol

 

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IGP LDP Synchronization

I implore all my readers to always remember this topic: IGP LDP synchronization. It is important to use IGP LDP synchronization to avoid blackholing, especially when MPLS networks fails to function effectively.

 

igp ldp synchronization

 

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Routing design

Understanding everything about routing design is no brainer, especially if you have the chart below on your wall.

The table below highlights the pros and cons of each routing protocol. Of course, you need to consider the design attributes shown in Figure A before embarking on routing design.

Should you like the comparison of the routing protocols illustrated in the table below or should you want to see similar comparison for other technologies, feel free to add your comment in the comment section.

Another boon for all my readers!

If you are interested in network design or considering CCDE, CCDP, or CCDA certification, you can subscribe for membership here so that you can peruse all the design resources (Videos , Tests , Case Studies , and E-Books).

Routing_Protocols_Comparison
Figure A: Comparison of Routing Protocols