What is the primary difference between GTPv1 and GTPv2?

GTPv1-C was used in 2G/3G networks, whereas GTPv2-C was introduced in 4G/EPC to support more complex session management and efficient signaling. GTP-U (User Plane) remains largely similar across versions.

What is a TEID in GTP?

A Tunnel Endpoint Identifier (TEID) is a unique 32-bit value used to identify a specific tunnel endpoint in a GTP-C or GTP-U connection. It allows nodes to multiplex thousands of user sessions over a single IP connection.

Usage: GTP Packet Visualizer

3GPP REL-15+EPC / 5GC

GTP_Handshake::Visualizer

Interactive sequence diagrams for GTPv2-C (Evolved Packet Core) and GTPv1 signaling. Simulate Control Plane procedures like Initial Attach and Handover using custom parameters.

Config_Params

Procedure_Type

Access_Point_Name

Subscriber_IMSI

>> Procedure: UE Initial Attach (GTPv2)

LIVE_SIGNALING_FLOW

GTPv2 Handshake Steps

Create Session Request: Initiated by MME to SGW over S11.
Bearer Context: Includes QoS profiles and TEID allocations.
TEID-C Allocation: Control plane identity for signaling stability.
S5/S8 Forwarding: SGW relaying request to PGW anchor.
User Plane Setup: Allocation of S1-U and S5-U TEIDs for data traffic.

Technical_Background

The GTPv2 (GPRS Tunnelling Protocol version 2) is the signaling backbone of the 4G/LTE Evolved Packet Core. It is standardized under 3GPP TS 29.274 and handles all session management capabilities between the MME (Mobility Management Entity), SGW (Serving Gateway), and PGW (PDN Gateway).

Unlike GTPv1, GTPv2 uses a more structured IE (Information Element) format, which allows for better extensibility and error handling in massive scale mobile networks.

Security_Implications

Signaling security at the GTP level is critical. Unauthorized Create Session requests can lead to IP hijacking, Denial of Service (DoS), or mass subscriber disconnection.

Fuzzing GTP-C packets can expose implementation flaws in Core nodes.
TEID predictability can allow an attacker to inject packets into another user's tunnel.
Interface security (S11/S5) usually requires IPsec or strictly firewalled private links.

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GTPv2 Handshake Steps

Create Session Request: Initiated by MME to SGW over S11.

Bearer Context: Includes QoS profiles and TEID allocations.

TEID-C Allocation: Control plane identity for signaling stability.

S5/S8 Forwarding: SGW relaying request to PGW anchor.

User Plane Setup: Allocation of S1-U and S5-U TEIDs for data traffic.

>> Procedure: UE Initial Attach (GTPv2)

GTPv2 Handshake Steps

Technical_Background

Security_Implications

Privacy_Protocol_v2.0

>> Procedure: UE Initial Attach (GTPv2)

GTPv2 Handshake Steps

Technical_Background

Security_Implications