Hi,
some hints from my experiences:
  - i highly recommend to uses filtering together with bridging, because there 
    could be many more packets going over the line, than you want
    to do so, configure your cisco's as follows:
    no bridge 1 acquire
    bridge 1 address 0800.09xx.xxxx forward BRI0 
    bridge 1 address 0800.09xx.xxxx forward Ethernet0 

In this example, the only addresses i let pass the router are the hp3000 and the dtc. These few statements saved us a lot of trouble with 'unwanted' packets. Of course, you have to replace the xx.xxxx by the mac-addresses of the hp3000 and the dtc. Also, BRI0 may be wrong with you cisco 1005/36xx.
To verify, if other addresses are currently forwarded, just enter the command 'show bridge' on the cisco command line.

By the way: we are currently using a remote dtc16mx with cisco 1003 on both sides over a  64k isdn-line and the performance is as if it was in the same office!

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HELP: Cisco routers slow DTC 16RX performanc
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