TSHOOT Notes

Network Maintenance Models:

ITIL – IT Infrastructure Library – Best practice for IT service management.

FCAPS – Fault, Configuration, Accounting, Performance and security – ISO model for network maintenance.

TMN – Telecommunication Management Network – ITU-T adapted model of FCAPS.

PPDIOO – Cisco method. Prepare, plan, design, implement, operate, optimize.

Configuring NIC Teaming in Linux

Link Bonding/NIC Teaming – In some scenarios, to increase the bandwidth we may need to bundle two or more physical interfaces to a single virtual bonding interface on the host. Below steps show how to configure link bonding (also called as port-channel) on a Linux host.

Configuring a Linux Host as NTP Server

 

• Network devices may need an NTP server to sync its clock; so that all devices in the network display same time…We can configure a Linux host as an NTP server.
• Check whether NTP daemon is installed in Linux: [Tested in RedHat-3.4.6]

Tcpdump

tcpdump – to dump the network traffic in Linux platforms.

Format: “tcpdump <options> <expressions>”

· By default, ‘tcpdump’ will dump traffic on first found lowest numbered interface from the list and continues to dump packets unless a stop signal is issued. (Ctr+C)

TCP-IP

• Five layers of TCP-IP protocol are;
  • Physical layer : deals with how bits are identified and transmitted, voltage values etc
  • Data-link layer: how the device on medium is identified and how it is accessed or shared and how the frame is constructed. Deal with MAC in case of ethernet medium.

L2 Security

• Interface command “switchport port-security” allows a single MAC to be learned on that port.
• Interface command “switchport port-security maximum x” to allow ‘x’ mac to learn on that port.
• To define static sticky MAC on an interface, use “switchport port-security mac-address x:x:x’

Wireless LAN

• IEEE 802.11 – standards for Wireless LAN ( WLAN).
• Every wireless connection is in half-duplex mode because transmitting and receiving stations use the same frequency
• The IEEE 802.11 standards use the CSMA/CA method to avoid collisions.

IP Phone

Power over Ethernet (POE):

• PoE devices like IP phones receive power from the connected switch.
• The switch can provide power in two different methods:
  • Cisco Inline power (ILP): Cisco proprietary.
  • IEEE 802.3af: Based on IEEE standard.

Software and hardware redundancy

Software Redundancy:

• Multilayer switches act as gateway for end users. First Hop Redundancy protocols (FHRP) are available to provide redundancy to end users.
• FHRP includes;

Hierarchical Network Design

• Three Layer Model:
  • Access layer: Where end users are connected. For intra-vlan routing.
  • Distribution Layer: where access layer switches are aggregated. For inter-VLAN routing
  • Core Layer: where distribution layer switches are aggregated. Center to all users.