Traffic/route can be controlled in loopback interface/physical interface

[wfqk]

Hi  Can we say data traffic(packet) would be controlled(sent out/in) only when the prefix is attached in physical interface? and route would be controlled(sent/in out) only when the prefix is attached in loopback interface or bgp policy, right? Thank you

[Jon Marshall]

Traffic can be forwarded as long as there is a route for the destination prefix, not sure how you are relating that to a physical interface.

Can you clarify what you are asking.

Jon

[wfqk]

Thanks for your reply. 

I mean the access-list can be attached to physical interface, which can control traffic. If the access-list is attached to loopback interface, the interface should control route, right? As we know, what bgp policy controls is route, instead of traffic, right? 

[Jon Marshall · Accepted solution]

Yes an acl attached to an interface controls traffic through that interface in the direction you apply the acl.

If the acl is attached to a loopback interface then the traffic would have to route through that interface to be controlled by the acl which I think is what you are saying.

Jon

[wfqk]

Great! BTW, both the traffic and packet should be same concept, and both route and prefix should be the same thing, right? Thank you

[Jon Marshall · Accepted solution]

Traffic consists of packets really at the IP layer so yes to that.

A route is more than just a prefix ie. it also contains a metric, a next hop etc. but I understand what you mean.

Jon

[wfqk]

Great and thank you!