Domain Name

    Whois Protocol to obtain information about a domain name. It uses TCP port 43 telnet 43 – search for the ?? – provides help There are two server modes: Thick – Stores all the data of the domain although it’s not the authoritative WHOIS Thin – Stores minimum data of… Read More »


Two modes: Multi mode – 200m maximum for 10GB and 500m for 1GB Single mode – from 500m to 50Km Cisco SFP are different part numbers depending on the fiber mode   Connectors LC – Lucent Connector SC – Subscriber Connector   Don’t mix fiber optic with fibre-channel. Fibre-channel is a transport protocol, initially designed to go over… Read More »

Cisco ISE – NAC – ACS

Cisco has three different products for similar proposes but with some differences: NAC, ACS and ISE. NAC – Network Access Control Features: AAA, Evaluate and Remediate for endpoints Cisco NAC provides Network Access Control for the devices connecting to the network through 802.1x. It can put devices into Quarantine. There are two additional modules: NAC Guest Server to provide client less… Read More »

Spanning Tree

Types of spanning tree: CST – Common Spanning Tree – 802.1q RSTP – Rapid Spanning Tree – 802.1w PVST – Per Vlan Spanning Tree – Creates one instance per VLAN and STP is run for each VLAN. MST – Multiple Spanning Tree – 802.1s – It’s possible to define the number of instances and which VLANs belong… Read More »

Cisco UC – Gatekeeper

See Cisco Unified Communications for architecture information   @Gatekeeper 1) Perform configuration in the central gatekeeper. configure terminal gatekeeper zone local CUCM1 [GK IP] zone local CUCM2 zone local GW1 zone local GW2 zone prefix CUCM1 [ROUTEPATTERN-CUCM1] gw-priority 10 [TRUNK_NAME]_1 //publisher zone prefix CUCM1 [ROUTEPATTERN-CUCM1] gw-priority 9 [TRUNK_NAME]_2 //subscriber zone prefix CUCM2… Read More »

Cisco UC – Gateways and SRST

Gateway Gateways are Cisco routers that have Voice Ports to connect to PSTN network and PVDM cards to transcode. Voice Cards Pri E1 -> VWIC-1MFT-E1 Bri ports -> VIC2-2FXO Analog devices (fax, mobile track) -> VIC-4FXS Data ISDN -> WIC-2BRI VWIC – Voice and WAN Interface Card (Voice + Data) VIC – Voice Interface Card (Only Voice) WIC – WAN Interface Card (Only Data)… Read More »

Cisco UC – CUCM – Communication Manager

See Cisco Unified Communications for architecture information   Infrastructure Setup System > Servers – List of servers that are part of the cluster: publisher, subscribers, presence,…. Subscribers should be defined here before the installation. It’s recommended to use IPs instead of Names. System > Cisco Unified DM – Autoregistration parameters. System > SRST – Definition… Read More »

VoIP general concepts

Voice Gateway Protocols MGCP – Media Gateway Control Protocol – Standard protocol based on a Master (Call Manager, CUCM) and a Slave (Voice ports of the gateway). Call manager decides where the call should be forwarded. H.323 – Standard and distributed protocol. The gateway decides where the call should be forwarded. H.323 is composed by H.225… Read More »

Cisco UC – CUBE – Border Element

CUBE CUBE – Cisco Unified Border Element is a SBC – Session Border Controller based on Cisco routers. It will be used as a central device when connecting different telephony systems through a SIP trunk and also to interconnect with a ITSP – Internet Telephony Service Provider that provides PSTN access through a SIP trunk. The codec… Read More »