Cisco Systems OL-16647-01 H.323 Inspection

24-11
Cisco ASDM User Guide
OL-16647-01
Chapter 24 Configuring Application Layer Protocol Inspection
H.323 Inspection
Figure 24-2 GPRS Tunneling Protocol
The UMTS is the commercial convergence of fixed-line telephony, mobile, Internet and computer
technology. UTRAN is the networking protocol used for implementing wireless networks in this system.
GTP allows multi-protocol packets to be tunneled through a UMTS/GPRS backbone between a GGSN,
an SGSN and the UTRAN.
GTP does not include any inherent security or encryption of user data, but using GTP with the security
appliance helps protect your network against these risks.
The SGSN is logically connected to a GGSN using GTP. GTP allows multiprotocol packets to be
tunneled through the GPRS backbone between GSNs. GTP provides a tunnel control and management
protocol that allows the SGSN to provide GPRS network access for a mobile station by creating,
modifying, and deleting tunnels. GTP uses a tunneling mechanism to provide a service for carrying user
data packets.
Note When using GTP with failover, if a GTP connection is established and the active unit fails before data
is transmitted over the tunnel, the GTP data connection (with a “j” flag set) is not replicated to the
standby unit. This occurs because the active unit does not replicate embryonic connections to the standby
unit.
H.323 Inspection
This section describes the H.323 application inspection. This section includes the following topics:
• H.323 Inspection Overview, page 24-12
• How H.323 Works, page 24-12
• Limitations and Restrictions, page 24-13
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Internet
Corporate
network 2
Corporate
network 1
Home PLMN
Gn
Gp
GRX
Roaming partner
(visited PLMN)
MS
SGSN GGSN Gi