08-01-2007 10:40 PM - edited 03-05-2019 05:39 PM
Hi Experts,
I have one switch, fa0/0 connected to Router which has dot1q at g0/1.2
But I am puzzling why the switch access mode desirable is not able to bring the vlan across to the router. As What i thought is desirable is an auto setting that will tag the router's dot1q.
COnfig as below:
Switch End
-----------
Interface FastEthernet0/0
switchport mode dynamic desirable
Router End
------------
interface GigabitEthernet0/1
ip address 16.11.22.254 255.255.255.0
ip helper-address 16.11.2.23
ip helper-address 16.11.1.23
no ip redirects
no ip proxy-arp
duplex full
speed 100
!
interface GigabitEthernet0/1.2
encapsulation dot1Q 2
ip address 16.11.20.254 255.255.255.0
ip helper-address 16.11.2.23
ip helper-address 16.11.1.23
no ip redirects
no ip proxy-arp
ntp disable
bridge-group 1
bridge-group 1 input-lsap-list 101
bridge-group 1 input-type-list 100
bridge-group 1 output-lsap-list 101
bridge-group 1 output-type-list 100
bridge-group 1 input-pattern-list 1200
Thanks in advanced..
Solved! Go to Solution.
08-01-2007 11:04 PM
Hi Cindy,
The command "switchport mode dynamic desirable" negotiates if the port should be access or trunk, and has nothing to do with which vlan the access port should be a member of.
Moreover, routers doesn't support DTP, and thus if your wish is to have the port as trunk you'll need to configure it with "switchport mode trunk" on the switch side.
HTH,
Mohammed Mahmoud.
08-01-2007 11:04 PM
Hi Cindy,
The command "switchport mode dynamic desirable" negotiates if the port should be access or trunk, and has nothing to do with which vlan the access port should be a member of.
Moreover, routers doesn't support DTP, and thus if your wish is to have the port as trunk you'll need to configure it with "switchport mode trunk" on the switch side.
HTH,
Mohammed Mahmoud.
08-02-2007 12:16 AM
Hi Mahmoud,
Great answer ya..:)
Understood.
Thanks!
08-02-2007 12:24 AM
Hi Cindy,
You are very welcomed :), i am glade that i've been informative, and thank you for using the rating system.
BR,
Mohammed Mahmoud.
08-02-2007 05:12 AM
A router cannot negotiate a trunk with desirable mode , thus all trunks from switches to routers must be forced on , "switchport mode trunk" . Desirable will work between switches or l2/l3 switches , options for each end would be desirable/desirable or desirable/auto on each end.
08-03-2007 06:43 AM
Thanks Glen.Make my understanding on this trunking related even better..:) appreciate that.
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: