When is there a performance hit when you subinterface a gigabit ethernet port?
We have a remote site with approxy 100-150 nodes. There is no layer 3 switch currently with which to implement VLANs. How bad of an idea is it to subinterface the router's inside interface to trunk down to the switch? There is a large amount of traffic traversing this router. While some traffic stays local for file storage and a few apps, a lot goes back to the hub site then out to the Internet. I was worried that the "hairpinning" might cause a performance hit. Currently there is no UC, but in the future there may be.
Thanks for the responses. Do either of you guys have any documentation to support?
I missed the 100-150 users but Paolo makes a very valid point. The 2821 supports 87Mb CEF throughput so if you have a large amount of traffic traversing the router then it will not be the subinterfaces so much as the actual capability of the router to forward packets.
As Paolo says, you would be much better off with a L3 switch such as the 3560/3750 which has much greater throughput and use the 2821 for WAN connectivity only.