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Wael Osama

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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Out of Band Management Networks – Console Servers

Building a robust out of band management network is a critical part of any service provider or large enterprise backbone. Although failures may not occur frequently but believe me if you are not prepared when they happen you will know how OoB management is important and critical. Network failures do happen for reasons ranging from human errors to power or hardware failures. One of your main objectives as a network designer is to keep your network available and achieve the highest possible up-time. There are a lot of things you can do to achieve these objectives in terms of redundancy …

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Cisco Profit up 79% Stock down 8%

Last Wednesday Cisco announced its fourth fiscal quarter financial reports. Cisco reported a 79% jump in profit however its stock price fell down by 8% in after hours trading as sales were slightly below analysts’ expectations. The question is Why this strong negative reaction? Lets take a closer look; the world is being very cautious recently about financial and economic indicators, no one really knows what is going to happen as economic and financial indicators are so confusing and showing mixed signals. Some indicators warn of  the possibility of a double dip recession while others indicate that things is still …

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