Command References
Tables 17-4 and 17-5 list configuration and verification commands used in this chapter. As an easy review exercise, cover the left column in a table, read the right column, and try to recall the command without looking. Then repeat the exercise, covering the right column, and try to recall what the command does.
Table 17-4 Chapter 17 Configuration Command Reference
|
Command |
Description |
|---|---|
|
interface type number.subint |
Router global command to create a subinterface and to enter configuration mode for that subinterface |
|
encapsulation dot1q vlan-id [native] |
Router subinterface subcommand that tells the router to use 802.1Q trunking, for a particular VLAN, and with the native keyword, to not encapsulate in a trunking header |
|
[no] ip routing |
Global command that enables (ip routing) or disables (no ip routing) the routing of IPv4 packets on a router or Layer 3 switch |
|
interface vlan vlan-id |
A switch global command on a Layer 3 switch to create a VLAN interface and to enter configuration mode for that VLAN interface |
|
sdm prefer lanbase-routing |
Command on some Cisco switches that reallocates forwarding chip memory to allow for an IPv4 routing table |
|
[no] switchport |
Layer 3 switch subcommand that makes the port act as a Layer 2 port (switchport) or Layer 3 routed port (no switchport) |
|
interface port-channel channel-number |
A switch command to enter PortChannel configuration mode and also to create the PortChannel if not already created |
|
channel-group channel-number mode {auto | desirable | active | passive | on} |
Interface subcommand that enables EtherChannel on the interface |
Table 17-5 Chapter 17 EXEC Command Reference
|
Command |
Description |
|---|---|
|
show ip route |
Lists the router’s entire routing table |
|
show ip route [connected] |
Lists a subset of the IP routing table |
|
show vlans |
Lists VLAN configuration and statistics for VLAN trunks configured on routers |
|
show interfaces [interface type number] |
Lists detailed status and statistical information, including IP address and mask, about all interfaces (or the listed interface only) |
|
show interfaces [interface type number] status |
Among other facts, for switch ports, lists the access VLAN or the fact that the interface is a trunk; or, for routed ports, lists “routed” |
|
show interfaces interface-id switchport |
For switch ports, lists information about any interface regarding administrative settings and operational state; for routed ports, the output simply confirms the port is a routed (not switched) port |
|
show interfaces vlan number |
Lists the interface status, the switch’s IPv4 address and mask, and much more |
|
show etherchannel [channel-group-number] summary |
Lists information about the state of EtherChannels on this switch, including whether the channel is a Layer 2 or Layer 3 EtherChannel |