Trunk Modes
Note
We recommend that both ends of a trunking link belong to the same port VSAN. On certain switches or fabric
switches where the port VSANs are different, one end returns an error and the other end is not connected.
Trunk Modes
By default, trunk mode is enabled on all Fibre Channel interfaces (Mode: E, F, FL, Fx, ST, and SD) on
non-NPV switches. On NPV switches, by default, trunk mode is disabled. You can configure trunk mode as
on (enabled), off (disabled), or auto (automatic). The trunk mode configuration at the two ends of an ISL,
between two switches, determine the trunking state of the link and the port modes at both ends (see
Trunk Mode Status Between Switches , on page
Table 24: Trunk Mode Status Between Switches
Port Type
E ports
Port Type
F and NP ports
Tip
The preferred configuration on the Cisco MDS 9000 Series Multilayer Switches is one side of the trunk set
to auto and the other side set to on.
Note
When connected to a third-party switch, the trunk mode configuration on E ports has no effect. The ISL is
always in a trunking disabled state. In the case of F ports, if the third-party core switch ACC's physical FLOGI
with the EVFP bit is configured, then EVFP protocol enables trunking on the link.
Trunk-Allowed VSAN Lists and VF_IDs
Each Fibre Channel interface has an associated trunk-allowed VSAN list. In TE-port mode, frames are
transmitted and received in one or more VSANs specified in this list. By default, the VSAN range (1 through
4093) is included in the trunk-allowed list.
Cisco MDS 9000 Series Interfaces Configuration Guide, Release 8.x
202
Your Trunk Mode Configuration
Switch 1
Switch 2
On
Auto or on
Off
Auto, on, or off
Auto
Auto
Core Switch
NPV Switch
On
Auto or on
Auto
On
Off
Auto, on, or off
202).
Resulting State and Port Mode
Trunking State
Trunking (EISL)
No trunking (ISL)
No trunking (ISL)
Trunking State
Trunking
Trunking
No trunking
Configuring Trunking
Table 24:
Port Mode
TE port
E port
E port
Link Mode
TF-TNP link
TF-TNP link
F-NP link