
112 ◾ Mobile Evolution: Insights on Connectivity and Service
to multiple SDFs. e SDF lters are applicable for uplink, downlink, or both uplink and down-
link information ows. ese lters use the 5-tuple of IP address (source and destination), port
number, (source and destination), and the protocol ID (UDP, HTTP, etc.) for matching the infor-
mation ows. e information ows are associated with user-specic services, such as le transfer,
email, web browsing, VoLTE, multimedia streaming, etc. To delineate separate PDNs, APNs are
utilized, and each APN has a separate default bearer. is is useful to distinguish PDNs associated
with the IMS f ...