CCNA R&S

                                Spanning Tree Protocol Spanning Tree Protocol (STP) Spanning Tree Protocol (STP) was developed to prevent the broadcast storms caused by switching loops. STP was originally defined in IEEE 802.1D .    Switches running STP will build a map or topology of the entire switching network. STP will identify if there are any loops, and then disable or block  as many ports as necessary to eliminate all loops in the topology.    A blocked port can be reactivated if another port goes down. This allows STP to maintain redundancy and fault-tolerance.    Ports are blocked to eliminate loops, STP does not support load balancing unless an EtherChannel is used. STP switches exchange Bridge Protocol Data Units (BPDU’s) to build the topology database. BPDU’s are forwarded out all ports every two seconds,   to a dedicated MAC multicast address of 0180.c...

       Introduction to Network and Protocol  1.Network Α network is simply defined as something that connects things together for a specific purpose. The term network is used in a variety of contexts, including telephone, television, computer, or even people networks. A computer network connects two or more devices together to share a nearly limitless range of  information and services , such as  Documents,  Email and messaging,  Websites,  Databases etc. A computer network connects two or more devices together to share information and services. Multiple networks connected together form an  internetwork.    2.Protocols Protocols are rules that govern how devices communicate and share information across a network.  Multiple protocols often work together to facilitate end-to-end network  communication, forming protocol suites or stacks.  Examples of protocols include:   IP – Internet Protocol HTTP - ...

                                        CCNA Routing and Switching Internetworking Devices and OSI Model     Introduction to Networking and Ethernet Introduction to Cisco and Router   OSPF  EIGRP   RIP   BGP  STP    DHCP DNS NTP  CDP  VLAN VTP  NAT DTP ACCESS-LIST  PPP  HSRP FHRP HDLC  PortFast and BPDU Guard   EtherChannel   Virtual Router  Redundancy Protocol   Gateway Load Balancing Protocol VPN   SNMP

1.Internetworking Models When networks first came into being, computers could typically communicate only with computers from the same manufacturer.  the Open Systems  Interconnection (OSI) reference model was created by the International Organization for  Standardization (ISO) to break through this barrier. The OSI model was meant to help vendors create interoperable network devices  and software in  the form of protocols so that different vendor networks could work in peaceable accord with each  other.  OSI model is the primary architectural model for networks. It describes how data and network information are communicated from an application on one computer through the network media to an application on another computer. The OSI reference model breaks this approach into layers.   2.Internetworking Device   Internet - Means combination of  LAN and WAN   Networking Device 1.  Switches 2. Router  3. Hubs 4. Repeaters 5. B...