Tag: networking

  • Installing Intel Omnipath 100G on Centos 7

    Intel Omnipath is 100G fabric a less expensive alternative for Mellanox 100G.. we recently bought 10 Racks of servers with 100G Omnipath . Until recently there is NO driver for Ubuntu , but i love centos so i kicked that in ..   Introduction to Intel® Omni-Path Architecture Intel OPA is the latest generation of […]

  • How Arp works in Linux

      To understand how ARP translates IP addresses to MAC addresses, consider the following example. Assume host A has an IP address of and a MAC address of fc:99:47:49:d4:a0, and wants to send a packet to host B with an IP address of Note that the network number is the same for both hosts, so host A is able to send frames directly […]

  • How Vlan works in plain language

    To understand how VLANs work, let’s consider VLAN applications in a traditional IT environment, where physical hosts are attached to a physical switch, and no virtualization is involved. Imagine a scenario where you want three isolated networks but you only have a single physical switch. The network administrator would choose three VLAN IDs, for example, […]

  • The meanings of SR、LRM、LR、ER and ZR

    SR、LRM、LR、ER、ZR are terms used in fiber optic communications, stand for the transmission distance of the 10G modules. SR stands for Short Range, these transceivers support link length of 300m over multi-mode fiber and use 850nm lasers. LRM means Long Reach Multimode, these transceivers support distance up to 220m over multi-mode fiber and use 1310nm lasers. […]

  • How to make Ubuntu as router for external traffic

    Due to limitations in public IPs you cant give all your hosts the publicly route-able IPs. but on otherside you want to install packages etc on those private host . One way is to enable a Public IP with a Host (we called it as gateway host) which has two network card , One network […]