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Network Design

Making sense of Broadband networks – VLAN Model

In the previous post we discussed the major considerations of a broadband network architecture. Now I want to discuss each of those points one by one adding some details. I will do this quick and might not be able to provide illustrations or configuration examples all the time due to time limits, so if anything is not so clear please let me know and I can reiterate this. Qouting from previous post, I was mentioing that a provider has to make a choice between two major VLAN models or combine both: “Which VLAN model? Customer VLAN (know as C-VLAN) or …

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Making sense of Broadband networks – Part 1

Broadband is a hot topic in the telecommunications industry nowadays; it is becoming the bread and butter for so many service providers and mobile carriers with the big growth and penetration rates in these technologies in the recent years.  ( Check this report about the EOCD countries). Although it is that important, broadband topics probably are not covered in any certification/education track and the reason might be that there is no “one shop suits all” in this field as in routing and switching technologies. In this post and others my aim is to provide some engineers with a brief but useful …

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7 Actions to get your network ready for IPv6

IPv4 is depleting so fast and time comes to get ready for IPv6. IPv6 may come to real life by 2012/2013. I am making a big claim here and I think I need to back it up with some facts: IPv4 address space is estimated to deplete somewhere in 2011. Check this Report. U.S government agencies are ready for IPv6 since June 2008. Large service providers are IPv6 ready or being ready now. Google your service provider. Content providers are preparing for IPv6. Google is one of the leaders in this transition. Just do a simple search to see the …

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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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