[QUOTE="slipstream_242"]\nHiya all.\n\nI`m trying to configure sub interfaces on my router but it doesn't seem to\nwant to know. I think I know what the problem is but would like to know if I\nam right or not.\n\ncan sub interfaces only be created on fastethernet ports? I have tried this\non a 2503 and a 2610 and get a message saying that ip routing is only\nallowed when configuring a sub interface as part of vlan configuration.\n\nThe ICND book I am working from shows the interface as fastethernet but the\nones on both of my routers are normal Ethernet and not fastethernet\n\nAny help would be appreciated.\n\nGordon\n[/QUOTE]\n\nSome 10mb ethernet interfaces do provide support for 802.1q. I do not think\nthe 2503 supports this. However I do believe that the 2610 with a > 12.2T\nIP Plus IOS will support this. You will need to change the encapsulation to\n802.1q to allow you to create and use sub interfaces.