MPLS Label Distribution: LDP Part3

So far so good, we have finished two parts of LDP and in this post we are going to explore another function of the four major functions of LDP. After an LDP session is initialized, LDP peers start to exchange label mappings according to the pre-negotiated parameters. In this post I will assume that LDP is using the most common label distribution modes for as follows: MPLS Label Space: Per platform label space. MPLS label retention mode: Liberal label retention. MPLS Label distribution mode: unsolicited downstream. MPLS Label control mode: Independent label distribution.

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It is time to make a CHANGE

One thing in life is not changing and that is that it is changing. We are networking guys; we know this better than anyone else, everyday we see a new technology coming or an old one diminishing. Somethings go and others come back. Bear with me a little; take a moment to think of your daily life from the time you get up in the morning to the time you go back to your bed; think of your routine, actions, thoughts, people you meet, transportation, etc. When was the last time you made a change? Even a simple one? Life …

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MPLS Label Distribution – LDP Part2

In my previous post I listed the main four functions of the label distribution protocol LDP and explained some concepts. In this post lets start dealing with the first two functions: Automatically discover LDP Peers in the same network segment. Establish and maintain LDP sessions with those peers. But I am not going to reinvent the wheel because I have already covered the two functions in older posts please have a look at them: LDP neighbor discovery, session establishment and maintenance. What is LDP extended discovery? We will soon do the next part, see you then.

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MPLS Label Distribution – LDP Part1

MPLS Label distribution protocol (LDP) as its name implies was defined to automatically create and maintain Label switched paths (LSP) in an MPLS network via label distribution. LDP specifications are defined in RFC 5036. In brief LDP assigns local label bindings to all IGP routes in the routing table and forms neighbor relationships with other LDP peers to exchange those local bindings. I will explain this further below. Label distribution Protocol (LDP) has four major functions as listed below: Automatically discover LDP Peers in the same network segment. Establish and maintain LDP sessions with those peers. Exchange and advertise label …

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How to: use IS-IS overload bit

Overload bit is special bit in the IS-IS LSP used to inform the network that the advertising router is not yet ready to forward transit traffic.  The overload bit was first intended for signaling overload or resource shortage on specific router for the rest of the network. You can use the command set-overload-bit intentionally on specific router to signal other routers not to use it as a transit hop in their SPF calculations. Typically this is done for a temporary situation like an overloaded router due to memory or processing shortage and released when the router recovers from the problematic …

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Before you buy a Console Server

In my post about out of band management networks I mentioned console servers as a mean of providing centralized remote access to network devices collocated in the same site. This post is a complementary post for the previous one if you are planning to use a console server in your out of band management network. Below are 7 questions to ask before you buy a console server: What access methods does this console server support?     ” Dial up, GSM, IP connectivity” How many serial console ports does the console server provide?    “No. of managed devices” How many Ethernet …

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