Cisco ASR 5000 Series Product Overview ▄  
  Transport Layer: UDP, TCP 
  Tunneling: 
  GTP: IPv4 or IPv6 GTP-C (signaling channel) and 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
 
 
S2a Interface 
This reference point supports the bearer interface by providing signaling and mobility support between a trusted non-
3GPP access point (HSGW) and the PDN Gateway. It is based on Proxy Mobile IP but also supports Client Mobile IPv4 
FA mode which allows connectivity to trusted non-3GPP IP access points that do not support PMIP. 
 
Supported protocols: 
 
  Transport Layer: UDP, TCP 
  Tunneling: GRE IPv6 
  Network Layer: IPv4, IPv6 
  Data Link Layer: ARP 
  Physical Layer: Ethernet