Cisco Systems RJ-45-to-AUX Auto, On or desirable mode, Desirable, Off, Nonegotiate, Isl, Dot1q

(vlans = 1..1005 An example of vlans is 2−10,1005) (trunk_type = isl,dot1q,dot10,lane,negotiate)

The different port negotiation types are described in Table 5.1, and the different trunk encapsulation types are described in Table 5.2.

Table 5.1: Port negotiation syntaxes for configuring VLAN trunks.

Variable	Description
auto	This trunking mode is used if the port uses DISL to
	initiate trunking. This is the default mode for Fast
	Ethernet and mimics plug−and−play. You cannot
	configure a trunk when both ends’ switch ports are
	configured for auto mode. One switch must be set to
	on or desirable mode.
desirable	This trunking mode, if using DISL, actively tries to
	configure itself as a trunk link. The other end of the
	trunk link must be configured to on or desirable to
	complete the trunk initiation.
off	This option disables the port from becoming a trunk.
	It is typically used when the device on the other end
	does not support ISL or IEEE 802.1Q. The port on the
	other end might be a 10Mbps Ether port or FDDI
	interface.
on	This option basically makes the port a trunk port,
	whether the other end is configured to be or cannot
	become a trunk. Use this option when the port on the
	other end does not understand DTP, such as a
	third−party adapter.
nonegotiate	Use this option when DISL negotiation that takes
	place on ISL trunks is not supported. When using
	dot1q as the final parameter, this option tells the
	switch that ISL will not be used for trunking the ports.
Table 5.2: Encapsulation type syntaxes that can be used when configuring VLAN trunk links.
Variable	Description
isl	Applies the ISL protocol encapsulation to an Ethernet
	trunk.
dot1q	Used for Ethernet trunks using the IEEE 802.1Q
	standard.
dot10	Used when assigning a FDDI trunk link to the port.
lane	Used when applying ATM to a trunk link port.
negotiate	Puts the port into permanent trunking mode. This
	option disallows the port from generating DTP
	frames. Typically, this command is used with
	switch−to−router trunks.

Let’s set port 2/1 as a trunk link using ISL with the following command:

5000> (enable) set trunk 2/1 on isl Port(s) 2/1 trunk mode set to on. Port(s) 2/1 trunk type set to isl.

5000> (enable) 2000 Dec 21 05:12:01 %DTP−5−TRUNKPORTON:Port 2/1 has become trunked.

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