Cisco ASR 5000 Series Product Overview ▄  
This reference point provides tunneling and management between the S-GW and the P-GW. The S8 interface is used for 
roaming scenarios. The S5 interface is used for non-roaming. 
 
Supported protocols: 
 
  Transport Layer: UDP, TCP 
  Tunneling: 
  GTP: GTP-C (signaling channel), GTP-U (bearer channel) 
  Network Layer: IPv4, IPv6 
  Data Link Layer: ARP 
  Physical Layer: Ethernet 
 
S-GW S5/S8 (GTP) P-GW
L1/L2
GTP-C/U
IPv4 / IPv6
IPv4 / IPv6
Transport
L1/L2
IPv4 / IPv6
IPv4 / IPv6
Transport
UDP UDP
GTP-C/U
 
 
 
S6b Interface 
This reference point, between a P-GW and a 3GPP AAA server/proxy, is used for mobility-related authentication. It 
may also be used to retrieve and request parameters related to mobility and to retrieve static QoS profiles for UEs (for 
non-3GPP access) in the event that dynamic PCC is not supported. 
 
Supported protocols: 
 
  Transport Layer: TCP, SCTP 
  Network Layer: IPv4, IPv6 
  Data Link Layer: ARP 
  Physical Layer: Ethernet