Question : 2611XM/3548XL - Subinterfaces and VLANs

I am experiencing issues assigning IP address when attempting to trunk multiple VLANs up to a single CISCO 2611 using subinterfaces.....

I have a CISCO 2611 XM and a CISCO 3548 XL...I am trying to use FA 0/0 with subinterfaces (2611) and vlan access [desired ports] (3548) to carry multiple VLANs.

192.168.100.0/24 [VLAN 100 on the 3548]
192.168.200.0/24 [VLAN 200 on the 3548]

-==2611==-
int fa 0/0.1
encap dot1q 100
ip address 192.168.100.0 255.255.255.0

int fa 0/0.2
encap dot1q 200
ip address 192.168.200.0 255.255.255.0

-==3548==-
int fa 0/1
switchport mode trunk (allowed all)

int fa 0/3
switchport mode access
switchport access vlan 100

I do not have any speed/duplex issues or any up/down issues.....I have dhcp pools setup for both and dhcp-server/networks setup per VLAN (problem ???)....I currently have no L3 management IP established on the 3548 so int VLAN1 remains up up....Obviously as soon as I revert back to a single network on fa 0/0 with no sub-ifs it works fine.

I have seen several proposed solution regarding "secondary" interfaces resolving several peoples issues with physical interface limitations but unfortunately that hasn't worked for me.

Answer : 2611XM/3548XL - Subinterfaces and VLANs

What is the problem?  Amongst other things, you might need "swit tru enc dot1q" (and if so, "swit tru enc dot1q non" would probably be better) on 3548 int f0/1 to force the trunking protocol.  Routers don't participate in DTP, so a switch expecting DTP might not trunk or might attempt ISL instead of dot1q.

You may also want to shutdown the 3548 int VLAN1 and create/setup an int VLAN 100 ...OR... 200, so that you can telnet to the 3548.