Free Network Tutorials Posts

It is recommended to implement the separation of management and data/customer traffic in your Datacenter switches like  Cisco Nexus devices (e.g. Nexus 7000, Nexus 9000).  Traffic passing through the management plane should be exclusively for management or administrative access purposes only like SSH, SNMP, NTP and AAA. Here’s the recommended configuration or practices for these management services. Configure Authentication, Authorization and Accounting (AAA) -preferably to setup centralized TACACS+ to manage all your devices, some uses Cisco® Identity Services Engine (ISE)…

Cisco

Fiber Optic Transceivers are wavelength-specific lasers that can convert electrical data signals into optical signals via optical fiber. It is basically a device that uses fiber optical technology in sending and receiving data. Here’s the classifications:   Based on form factors 1. XENPAK – original 10G pluggable optics using SC connector type 2. X2 -provides 10G connectivity up to 40km on SMF and successor of XENPAK. Also used SC connectors 3. GBIC -short for Gigabit Interface Converter, is a standard…

Datacenter Networking

Autonomous System or AS is a set of routable IP prefixes that belongs to a network or collections of networks managed by a single entity such as ISP, corporate network, university, etc. and maintain a single or common routing policy. Each AS has to be represented by unique number called Autonomous System Number or ASN to control and exchange routing information with others. Two formats of ASNs: 2-byte ASN (16-bit number) –> provides for 65,536 ASNS (0 to 65535) .…

Networking

Fiber Optic Cable Connectors provide alignment of microscopic glass fibers  used in fiber cables in transmitting high speed data.  These are the types of fiber optic cable connectors that you will come across in a datacenter. There’s few more that I excluded in the list as already obsolete and seldom use. 1. SC (Standard/Subscriber/Square Connector) -most popular type used in telecomm/datacomm industry for its durability, low-cost and simple installation. It uses locking tables and classified as push-pull connectors. -ferrule diameter…

Datacenter

It is good to know these types of power cables/plug in case you need to bring up servers from external parties. Normally servers are C13 plug but the other end can be different depending on the rack you have, (country specific). These are the common types that you need to be familiar with if you work in a datacenter or somewhere you do server hosting.   C14 NEMA5-15 – Type B NEMA6-15 BS1316 – (UK 3 pin) CEE7/7 – Type…

Datacenter

As mentioned from the previous post, Bogon prefixes or routes should never appear in the Internet routing table. Network Engineers should implement “Best Practices” in their network, that includes filtering of bogons as it maybe used in DDoS attacks or Spams. Refer to https://freenetworktutorials.com/ipv4-and-ipv6-bogon-address-list  for more info. “Martians” bogons may changed occasionally so at least make sure private address mentioned in https://freenetworktutorials.com/ipv4-classful-and-reserved-addresses are filtered so it wont leak out into the Internet. Here is sample steps and configuration. (This is the equivalent configuration…

Juniper

As mentioned from the previous post, Bogon prefixes or routes should never appear in the Internet routing table. Network Engineers should implement “Best Practices” in their network, that includes filtering of bogons as it maybe used in DDoS attacks or Spams. Refer to https://freenetworktutorials.com/ipv4-and-ipv6-bogon-address-list  for more info. “Martians” bogons may changed occasionally so at least make sure private address mentioned in https://freenetworktutorials.com/ipv4-classful-and-reserved-addresses are filtered so it wont leak out into the Internet. Here is sample steps and configuration. 1. Create the Ingress…

Cisco

In routing world, Administrative Distance refers to the reliability of the routing protocol. It is equivalent to Juniper’s Route Preference and Huawei’s Preference. It is important to consider these values as in the scenario that there are multiple routes to a destination (with same prefix length), the route (learned via the routing protocol) with the lowest value is preferred. Table below will show the values for respective platform.   Routing Protocol Cisco(AD) Juniper (RP) Huawei(P) Connected Interface 0 0 0…

Networking

Dynamic Host Configuration Protocol, or DHCP, is a network protocol used (via DHCP server) to dynamically or automatically assign IP address and other info (e.g.Gateway,DNS) to each hosts in the network. Here’s a sample configuration of running DHCP server in a Layer 3 switch. Host Setup: Gateway: 192.168.10.1 Netmask: 255.255.255.0 DNS Server: 192.168.20.254, 8.8.8.8 Layer 3 Switch(tested in Cisco 49xx) VLAN ID: 888 IP Block: 192.168.10.0/24   Fig.A. Hosts connected to switch Configure respective interfaces for access vlan L3-Switch#conf t…

Cisco

UTP or Unshielded Twisted Pair is a type of copper cabling used in LANs and has several categories based on the TIA/EIA 568 standard namely as CAT3,CAT4,CAT5,CAT5E and CAT6. Common connector used with these UTP cables are RJ-45. Most common used now are CAT5e as it supports up to 1Gbps for 100 meters, and now CAT6 is becoming popular to LAN and datacenter networks as it supports 1Gbps for 100 meters and up to 10Gbps for 50 meters. As of…

Networking