"switchport trunk encapsulation" not supported in Cat4500 IOS XE 3.5

[jesnowakb]

Hi everyone!

I'm configuring a Cat4500 with IOS XE 3.5 and the command  "switchport trunk encapsulation dot1q" it's being rejected, apparently the command " switchport trunk encapsulation" is not supported, but I have being looking in the Configuration Guides and the command is used with no problem. Could someone tell me what is the problem with this command?

SW1(config-if)# switchport trunk encapsulation dot1q
                                         ^
% Invalid input detected at '^' marker.

SW1(config-if)# switchport trunk allowed vlan 259,260
SW1(config-if)# switchport mode trunk

SW1(config)#interface GigabitEthernet2/31
SW1(config-if)#switchpo
SW1(config-if)#switchport trunk ?
  allowed  Set allowed VLAN characteristics when interface is in trunking mode
  native   Set trunking native characteristics when interface is in trunking
           mode
  pruning  Set pruning VLAN characteristics when interface is in trunking mode

SW1(config-if)#switchport trunk

SW1#sh ver
Cisco IOS Software, IOS-XE Software, Catalyst 4500 L3 Switch Software (cat4500e-UNIVERSAL-M), Version 03.05.03.E RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2014 by Cisco Systems, Inc.
Compiled Mon 05-May-14 10:33 by prod_rel_team

Cisco IOS-XE software, Copyright (c) 2005-2013 by cisco Systems, Inc.
All rights reserved.  Certain components of Cisco IOS-XE software are
licensed under the GNU General Public License ("GPL") Version 2.0.  The
software code licensed under GPL Version 2.0 is free software that comes
with ABSOLUTELY NO WARRANTY.  You can redistribute and/or modify such
GPL code under the terms of GPL Version 2.0.  For more details, see the
documentation or "License Notice" file accompanying the IOS-XE software,
or the applicable URL provided on the flyer accompanying the IOS-XE
software.

ROM: 15.0(1r)SG5
quiswdtsdp1 uptime is 1 hour, 32 minutes
Uptime for this control processor is 49 minutes
System returned to ROM by SSO Switchover
System restarted at 19:18:25 EC Fri Aug 7 2015
Running default software
Jawa Revision 7, Snowtrooper Revision 0x0.0x1C

Last reload reason: redundancy reset

License Information for 'WS-X45-SUP7-E'
    License Level: entservices   Type: Permanent
    Next reboot license Level: entservices

cisco WS-C4507R-E (MPC8572) processor (revision 11) with 2097152K bytes of physical memory.
Processor board ID FOX1304G9TR
MPC8572 CPU at 1.5GHz, Supervisor 7
Last reset from Reset by peer
1 Virtual Ethernet interface
102 Gigabit Ethernet interfaces
8 Ten Gigabit Ethernet interfaces
511K bytes of non-volatile configuration memory.

Configuration register is 0x2101 (will be 0x0 at next reload)

Thanks!

[Karsten Iwen]

This command is used to choose the encapsulation if the switch not only supports the standard 802.1q, but also the older Cisco non-standard ISL (Inter-Switch-Link). If this command is not available, then the Switch is only capable of using .1q and there is no need to configure it.

[Steve Fuller]

Hi,

It's likely that IEEE 802.1Q is the only encapsulation type supported and so the command switchport trunk encapsulation has been removed. That's certainly the case on other platforms (see C3020 blade switch doesn't accepting dot1q on trunk link?)

To check, use the command show interface <interface> capabilities and see what options there are for the Trunk encap. type.

Regards

[Pawan Sharma]

Only encapsulation supported in Cisco IOS XE is 802.1q. ISL is an old story which nobody does in Cisco now. So, dot1q is the only option, it doesn't allows customisation.

HTH.