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MPLS Layer 3 VPN Deployment

MPLS Layer 3 VPN Deployment

In this post I will explain MPLS Layer 3 VPN deployment by providing a case study. This deployment mainly will be for green field environment where you deploy network nodes and protocols from scratch. This post doesn’t cover migration from Legacy transport mechanisms such as ATM and Frame Relay migration as it is covered  in the separate post on the website. Read more

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MPLS Transport Profile (MPLS-TP) Basic Explanation and Key Points

MPLS Transport Profile (MPLS-TP)

Multi-Protocol Label Switching Transport Profile (MPLS-TP) is a new technology developed jointly by the ITU-T and the IETF. The key motivation is to add OAM functionality to MPLS in order to monitor each packet and thus enable MPLS-TP to operate as a transport network protocol.

 

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MPLS over IP Encapsulations and Comparison between MPLS over LSP

Do you need an LSP for MPLS ?

In this post, I will go through below topics. This is one of the points which network engineers struggle to understand as I have seen.

  • What is an LSP (Label Switched Path) ?
  • What was the purpose of having LSP in the first place?
  • Do we need an LSP for MPLS and MPLS Applications such as 2547 VPNs ?
  • MPLS over LSP vs. MPLS over IP Encapsulations
  • MPLS VPN  infrastructure in 2017

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Benefits of MPLS – Why MPLS is used ? – MPLS Advantages

Benefits of MPLS, Why MPLS is used on today networks and the Advantages of MPLS will be explained in this post.

As an Encapsulation and VPN mechanism, MPLS brings many benefits to the IP networks. In this article most of them will be explained and design examples will be shared by referring more detailed articles on the website as well.

Below list shows the benefits of MPLS. Although this may not be the full list, comment section always open for your comment and questions.

 

  • Faster packet processing with MPLS compare to IP

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BGP in MPLS Layer 3 VPN – BGP as a PE-CE Routing Protocol

BGP can be used as a PE-CE routing protocol in MPLS Layer 3 VPN. Also Service Providers run MP-BGP (Multiprotocol BGP) if they have MPLS Layer 3 VPN.

In this article, MP-BGP will not be explained since it has been explained here earlier in detail.

When BGP is used as a PE-CE routing protocol between the customer and its MPLS Layer 3 VPN Provider, it is important to say that there is no need to redistribute on the Service Provider PE. All the other routing protocol require redistribution from MP-BGP into the routing protocol and vice versa.

In this post, I will explained what are the design considerations when BGP is used as PE-CE routing protocol in MPLS Layer 3 VPN and the how you can mitigate possible routing loop problems.

Last but not least, I will share when CE (Customer Equipment) is multihomed to two PEs (Provider Edge Device), what would be the design considerations if BGP is used in MPLS Layer VPN. Read more

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Inter-AS Option AB (a.k.a Option D)

Inter-AS Option AB is also known as Option D or Hybrid Inter AS Option. It is called Hybrid because Inter-AS Option B uses the best capabilities of Inter-AS Option A and Inter-AS Option B. These capabilities will be explained throughout this post.

MPLS VPN providers often need to inter-connect different ASes to provide VPN services to customers.

Inter-AS Option AB first deployed by Cisco but today many vendors including Juniper provides Inter-AS Option AB feature.

But what are the best capabilities of the Inter-AS Option A and Inter-AS Option B ? Read more

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What is MPLS tunnel label and why it is used ?

In networking we use many times different terms to define the same thing. MPLS tunnel label or transport label are just two of those.

Not only transport and tunnel labels but also other terms are used to define the same thing which these labels provide.

Let me explain first why and where MPLS tunnel label is used. Read more

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What does PE-CE mean in MPLS ?

What does PE-CE mean in the context of MPLS ? What is CE , P and PE device in MPLS and MPLS VPN ?

These are foundational terms and definition in MPLS.

MPLS is one of the most commonly used encapsulation mechanism in Service Provider networks and before studying more advanced mechanisms, this article is must read.

In order to understand PE-CE, we need to understand first what are PE and CE in MPLS.

Let’s take a look at below figure.

MPLS VPN PE-CE

Figure -1 MPLS network PE, P and CE routers Read more

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MPLS Design Question

MPLS Design Question – MPLS is one of the most commonly used encapsulation method today. Especially on Wide Area Networks of the Service Providers, Large Enterprises and some datacenters.

Service Providers sell MPLS services to customers for decades. When customers want to have Service Provider redundancy so two MPLS circuit from different Service Providers, Inter AS MPLS service is created between those providers.

Or customers have a location where their MPLS service provider don’t have there but customer wants to have end to end MPLS connectivity between their all locations, again Inter MPLS Service is created between the providers.

If you are a visual learners and want to understand the basics of Inter AS MPLS VPN Options, check my youtube channel and subscribe for the more design videos.

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What does BGP free core mean ?

What is the meaning of BGP free core?

BGP refers to an Internet protocol used between different Autonomous System on the Internet. The purpose of this post is not to explain the fundamentals of BGP, as I believe that readers are already familiar with the basic of BGP and IP routing operation. To understand the rudimentary aspect of BGP, click here to peruse articles on BGP.

Let’s look at the topology shown below to understand the BGP operation and IP destination-based lookup. Read more

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What is RSVP-TE ?

What is RSVP-TE (RSVP Traffic Engineering)? 

RSVP-TE refers to a resource reservation protocol that is invented in order to allocate a bandwidth for the individual flows on the network devices.

To say it another way, RSVP-TE are extensions to the RSVP protocol specified in the RFC 3209.

Although, RSVP-TE has been initially invented as a Quality Service Mechanism in an Intserv QoS architecture, it has never been used in modern networks due to scalability problems.

This is also because allocating tremendous number of flows on the networking nodes creates scalability problems. Read more

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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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Why Should You Place Less Emphasis on MPLS Traffic Engineering

If I input MPLS traffic engineering on any search engines, I will find about 100 articles on the internet providing the same explanations about MPLS traffic engineering.

But unfortunately, nobody ask these questions: do I really need it? What are the reasons behind the implementation of MPLS Traffic Engineering?

Would it worth the time and energy to deploy and learn such a complex technology if there are many easier, resource-friendly alternatives.

In this article, I will explain all the answers to these questions.  Undoubtedly, MPLS traffic engineering has many used cases and it helps to solve numerous problems in an MPLS enabled networks.

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Dual Carrier MPLS VPN Design

For the purpose of high availability, critical locations of company A – a customer of VPN service provider – is connected to two different carriers. However, this connectivity requires an important design consideration.

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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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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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Advanced Carrier Supporting Carrier Design

LDP is the most commonly used label distribution protocol in today MPLS networks. Although it lacks of Traffic Engineering, Admission Control, Fast Reroute capabilities, it scales very well because of its Multi Point to Point Label Switched Path.BGP can also assign a label for the IP and also for the VPN prefixes and in this article I will show you how BGP provides extra level of scalability for the MPLS applications.

LDP can also be used to setup a targeted LDP session which is used by many applications such as L2VPNs, Remote LFA Fast Reroute, LDP over RSVP to scale RSVP networks and so on.

In this post I will explain the differences if you use IGP + LDP and the BGP + Label for the IP prefixes.

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What does really MPLS layer 2 VPN mean ?

Couple days before I received an email from one of my readers ( Ahmet Eris )  related with his design. He designed a network infrastructure for his customer and wanted me to take a look as well.

But I realized that Ahmet has some misunderstanding on the usage of MPLS layer 2 VPNs and I thought just briefly mentioning about it can help to my other readers as well. Read more

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Seamless MPLS

Seamless MPLS architecture can be used to create large scale MPLS networks, reduce operational touch points for service creation, reduce overall complexity and enable flexible service creation points in the Service Provider networks.

Seamless MPLS architecture is best suited to the very large scale service provider networks that have 10s or 100s of thousands access nodes and very large aggregation networks ,but still want to have a predictable,proven control planeRead more

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Carrier Supporting Carrier – CSC

[follow_me]CSC Carrier Supporting Carrier is a hierarchical MPLS VPN architecture between the Service Providers.

Service is an MPLS VPN service mostly but doesn’t have to be as you will see throughout the post. Read more