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Understand MTU and MRU – The Full Story

MTU or Maximum transmission unit is a topic that pops up every once in a while in different discussions. Although it’s a simple concept, it causes a lot of confusion specially for those who are new to the field. MTU typically becomes an issue of concern during network changes, like adding new vendors equipment or upgrading to a new software. One reason for that is the difference in  implementations used by different vendors or even between different OS versions or equipment  from the same vendor. Here is an example for such confusion  MTU and ping size confusion. On the other …

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Private IP address ranges

IPv4 Private Address Ranges:   10.0.0.0/8 IP addresses: 10.0.0.0 — 10.255.255.255. 172.16.0.0/12 IP addresses: 172.16.0.0 — 172.31.255.255. 192.168.0.0/16 IP addresses: 192.168.0.0 – 192.168.255.255   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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Jumbo Frames

In the past few days we have been doing some tests for Ethernet MTU “The never ending story” in our MPLS backbone.  Playing with MTU for long may have bad effects on your health on the long run but is still a must to have an operational network. We have tested a lot of things about packet fragmentation in the MPLS backbone, the appropriate MTU size when running ATOM and other MPLS services. We may share these tests when we write up a good documentation. One of the interesting topics I would like to share with you is Jumbo frames; …

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ARP Caching and Timeout

From time to time I find myself craving to the fundamentals; I do this for two main reasons, the first one is that fundamentals are the building blocks of all complex networking topics and deeply understanding them makes a better engineer, the second one is longing to simplicity after doing some complex tasks. One of these fundamentals that is worth reviewing is the Address Resolution Protocol, this protocol is one of the main building blocks of any network existing on earth today.

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