RFC 3455 P-Access-Network-Info header.
The syntax of the P-Access-Network-Info header is described as
follows:
P-Access-Network-Info = "P-Access-Network-Info" HCOLON
access-net-spec
access-net-spec = access-type *(SEMI access-info)
access-type = "IEEE-802.11a" / "IEEE-802.11b" /
"3GPP-GERAN" / "3GPP-UTRAN-FDD" /
"3GPP-UTRAN-TDD" /
"3GPP-CDMA2000" / token
access-info = cgi-3gpp / utran-cell-id-3gpp /
extension-access-info
extension-access-info = gen-value
cgi-3gpp = "cgi-3gpp" EQUAL
(token / quoted-string)
utran-cell-id-3gpp = "utran-cell-id-3gpp" EQUAL
(token / quoted-string)