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Is the trunk set as ISL or 802.10?

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zee7

Technical User
Aug 28, 2003
18
AU
Hello,

I have a question about the config I have pasted below. In the config below, it says VLAN ISL Id: 1002....but it then states VLAN 802.10. Does this mean that the trunk is running 802.10 or ISL?

switch1(vlan)#show
VLAN ISL Id: 1002
Name: fddi-default
Media Type: FDDI
VLAN 802.10 Id: 101002
State: Operational
MTU: 1500
VLAN ISL Id: 1004
Name: fddinet-default
Media Type: FDDI Net
VLAN 802.10 Id: 101004
State: Operational
MTU: 1500

Help is much appreciated.

 
Neither. FDDI numbers VLANS with a SAID that is 100000 plus the VLAN number. You're seeing 101002. The "normal" VLAN ID is 1002 which is the way ISL and dot1q would see the VLAN. If you want to see the trunk information (depending on your switch model), try a show interfaces fa x/x switchport for dot1q or show interfaces fa x/x trunk for ISL.
 
Hey Clue bird! What I really want to do is setup trunking on interface GigabitEthernet0/2, and I am connecting this interface to a non-cisco device. Any suggestions? Thanks

interface FastEthernet0/23
duplex full
speed 100
switchport access vlan 74
!
interface FastEthernet0/24
switchport access vlan 74
!
interface GigabitEthernet0/1
switchport mode trunk
!
interface GigabitEthernet0/2
 
Try this:

shutdown !turn off interface while configuring
switchport trunk encapsulation dot1q
switchport trunk allowed vlan X,Y,Z !If you don't specify explicitly what VLANs to allow, then all will be permitted
switchport trunk
switchport nonegotiate !turns off DTP since you've forced trunking
switchport trunk native vlan X !Specify the native VLAN if not VLAN1
no shutdown

That should do the trick based on what you've posted.
 
If I enter the command switchport trunk native vlan1....does it look like from the config I pasted that VLAN1 is the native VLAN. I can email you the complete config if you do not mind?

interface VLAN1
no ip address
no ip directed-broadcast
no ip route-cache
shutdown
 
Hi Cluebird,
Thanks for all your help so far! The following are the steps I am taking...if there is a question mark next to the command, this means that it is not recognized.

config# int GigabitEthernet 0/2
config-if# shutdown
config-if# switchport trunk encapsulation dot1Q
config-if# switchport trunk allowed VLAN all
config-if# switchport nonegotiate ?(this is not an option?)
config-if# switchport trunk native VLAN1
config-if# no shutdown

Also could I set the trunk using the command set trunk, and why do I use switchport trunk. I know my config is setup with switchport, but what is the difference?

Thanks again!
 
The command syntax varies based on your switch model. Older switches use CatOS which is a series of commands that start with the "set" keyword. Newer switches use IOS, however the commands available depend on whether you're using a Layer 2 or Layer 3 image. What switch model are you using?
 
I did a sh hardware...and it came up with this.

Cisco Internetwork Operating System Software
IOS (tm) C3500XL Software (C3500XL-C3H2S-M), Version 12.0(5.2)XU,
cisco WS-C3524-XL (PowerPC403) processor (revision 0x01) with 8192K/1024K bytes
of memory.
Processor board ID FAB0514V1DM, with hardware revision 0x00

Also as I have to setup trunking on G0/2. I was a bit confused on what g0/1 is actually setup for? Below is the config of this interface. Do you know what g0/1 is setup for? Particularly switchport mode trunk ?

sh run
interface GigabitEthernet0/1
switchport mode trunk
!
interface GigabitEthernet0/2
!
 
Are you trying to set up trunking on the two GigabitEthernet ports and then channel them or are you trunking to two different switches? Your hardware should support both dot1q and isl. If you're connecting to a non-Cisco device, the dot1q is the open standard.

Your trunk configuration should look something like this:
Switch(config)#interface GigabitEthernet 0/2
Switch(config)#shutdown
Switch(config-if)#switchport mode trunk
Switch(config-if)#switchport trunk encapsulation dot1q
Switch(config-if)#switchport nonegotiate
Switch(config-if)#switchport trunk allowed vlan all
Switch(config-if)#no shutdown
Switch(config-if)#exit
Switch(config)#interface VLAN 1
Switch(config-if)#ip address 10.1.1.5 255.255.255.0
Switch(config-if)#no shutdown
Switch(config-if)#exit
Switch(config)#ip default-gateway 10.1.1.1
Switch(config)#end
Switch#write mem

You'll have to configure the other switch for the trunking as well.
 
Thanks Cluebirdfor all your help!!
 
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