Cisco Router useful tips and Commands

802.1D IEEE specification for STP.

Root bridge Switch that includes the designated port with the highest priority or the lowest MAC address.

Spanning-tree algorithm (STA) System used to calculate a loop-free network topology for STP.

Spanning Tree Protocol (STP) A protocol that uses the spanning- tree algorithm to map the best path through the network and block ports that can create a redundant path for data in the network.

Frame tagging Method used to identify frame membership in a VLAN as the frame traverses a trunked link.

Inter-Switch Link (ISL) Cisco proprietary method of frame tagging for Fast Ethernet and Gigabit Ethernet links.

Static VLAN Assignment of a switch port to a VLAN by an administrator.

Virtual local area network (VLAN) A logical grouping of network users and resources connected defined ports on the switch. A VLAN looks like, and is treated like, its own subnet.

show cdp neighbor Display a summary of connected cdp devices

show cdp entry * Display detailed information on all devices

show ip protocols Display current routing protocols

show ip route  Display IP routing table

show access-lists Display access lists, this includes the number of displayed matches

show isdn status Check the router can see the ISDN switch

show frame-relay pvc  Check a Frame Relay PVC connections

show frame-relay lmi show lmi traffic stats

show frame-relay map Display the frame inverse ARP table

Enable Enter privileged mode

disable Return to user mode from privileged

Logout or exit or quit  Exit Router

up arrow or <Ctrl-P> Recall last command

down arrow or <Ctrl-N> Recall next command

<Shift> and <Ctrl> and 6 then x Suspend or abort

<Ctrl-R> Refresh screen output

TAB Compleat Command