When trying to finalise my PSTN configuration for the required E1 and T1 lines to HQ, BR1 and BR2 I stumbled into a set of limitations with the 2801 router that caused me to stop and redo my topology.
Originally I had the following setup:
The 2801 was configured as follows
Slot0-VWIC2-2MFT-T1/E1 (T1 crossover to HQ and BR1 )
Slot 1-VWIC2-2MFT-T1/E1 (E1 crossover to BR2)
Frame relay switching was enabled with no issues for all three sites but when I tried to enable the pri timeslots on the controller in slot 0, I kept getting an error saying insufficient resources. At first I wasn’t sure what was wrong so moved on to the controller in slot 1 and configured the E1 pri timeslots with no problems. A quick google lookup pointed out that the 2801 routers can only use a T1 CAS voice card in slot 0 and nothing else. As the lab scenarios for HQ and BR1 required PRI and I was out of slots to relocate to, I now have to use the 2801 as a site router and replace it with a 2811 router instead.