Question: In a MIP tunnel, as defined by the Tunnel-Header-Filter AVP (AVP code 1036) of type IPFilterRule, what does the "Direction" parameter signify, and how are its values interpreted in the context of data flow?
Option 1: Direction indicates the protocol used for tunneling, with "in" signifying TCP and "out" signifying UDP.
Option 2: Direction specifies the traffic flow direction relative to the network, with "in" referring to uplink (UE to network) and "out" referring to downlink (network to UE).
Option 3: Direction determines the action taken on packets, with "in" meaning permit and "out" meaning deny.
Option 4: Direction is used to specify the type of IP address, with "in" for IPv4 and "out" for IPv6.
Explanation: The correct interpretation of the "Direction" parameter in the context of the Tunnel-Header-Filter AVP is related to the flow of traffic. Understanding this is crucial for configuring proper filtering rules that apply to the tunnel payload’s QoS. The direction "in" signifies uplink traffic (from the User Equipment (UE) to the network), and "out" signifies downlink traffic (from the network to the UE), ensuring that Quality of Service (QoS) rules are applied appropriately based on the traffic’s direction in a Mobile IP (MIP) tunnel.