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What Is ?

Software-Defined Networks .. A Primer


SDN, Software-Defined Networking, the trending technology that some friends/colleagues of mine like to refer to it as “Still Does Nothing”. Let’s see if it does some thing. SDN has been a market hype for few years now.  Out of laziness, I ignored it in the beginning then I had to catch up a bit later and learn what was exactly going on.  From who I know many engineers have taken the same path and are still ignoring SDN, probably out of the feeling that we have enough to learn something new. Lately, SDN has been reduced to a buzzword that …

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Making Sense of Broadband networks: PPPoE Explained

A bit of background First .. PPPoE stands for Point to Point over Ethernet and is the successor of PPPoA. PPPoE is simply a method of encapsulating PPP packets into Ethernet frames. The standard is defined in RFC2516 . IPoE is growing very quickly but as far as I can tell PPPoE is still very widely deployed model in broadband networks. PPP protocol is a very mature protocol that was originally implemented to create and maintain direct connections between two nodes. PPP is such a protocol that provides many features but the one that is most interesting to broadband providers is the ability …

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What is MTU?

MTU stands for Maximum transmission unit, which is the maximum packet length that can be sent on an egress interface toward a destination. MTU is an attribute of the egress interface and is typcially considered over a full path from the source to destination. MTU size differes from one media to another and is often a source of issues when configured incorrectly in the network. The following posts will give deep understanding for What is MTU and how you can manipulate it and set it to the correct value. Understanding MTU and MRU .. The full story The post starts …

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Private IP address ranges

IPv4 Private Address Ranges: IP addresses: — IP addresses: — IP addresses: –   Private IPv4 internet address ranges are defined in RFC1918 with the motivation to control growth of the internet routing tables and to preserve IPv4 addresses space to extend it’s life. The private ranges defined in this RFC are not routable over the internet and are intended for internal use only in private Internets/Intranets and that means these packets destined to these ranges will not be routable across the internet and should stay within the private network. …

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IPv6 Tutorial: The overview

I will start from the beginning; two weeks ago I wrote a post claiming that IPv4 is depleting and IPv6 is coming soon; and since we are considering deploying IPv6 soon in our network, I thought it might be useful to write about IPv6 migration and transition strategies. Although, this is important but I think the readers of this blog including me will benefit more if we start at the beginning even if it takes longer to get where I wanted to start. I will start small and build up as we go toward the new IPv6 internet. Get yourself …

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What is MPLS?

What is MPLS? MPLS stands for Multi-protocol Label Switching. MPLS is a packet forwarding technology that is capable of carrying any L3 protocol and here comes the word multi-protocol. MPLS is capable of tunneling L3 packets inside the MPLS network using  MPLS labels. The MPLS label is pushed into the packet between the layer two header and the layer three header of the packet at the ingress router and is used to switch the packets across the network to its destination. What is the MPLS Label and How is it used? The MPLS label is a fixed 4 byte identifier …

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