Can I config EtherChannel Between Catalyst Switches 3550 and a Cisco Router such as 7200 ?Please help me ?

I have a Lan . In the lan there are a 3600 router and seven 1750 router .I use eigrp protocol on ethernet interface .And i use the eigrp authentication md5. In these router ,the 3600 ios is 12.2(2)t, some 1750 router ios is 12.2(8)y8.otehr 1750 ios...

when ong i ping from 2600 to other router through ddn.the time average is 140 ms. the interface bandwitdh is1.54M by encapsulation ppp. the time is too long ?why ?

Hi: I have a router 2611 . -------[e0/1]router[e0/0]------device----- the device is turn optic singal to ethernet singal. At e0/0 I want to config ip address 192.168.1.2/30 . config t int e0/0 ip address 192.168.1.2 255.255.255.252 ...