Echo Response

These messages are sent from the controller to the GGSN server or vice versa. The table below lists the message attributes.

Table 1. Echo response attributes
Attribute Presence Type Description
Flags:
  • Version
  • Protocol type
  • Spare bit
  • Extension header
  • Sequence number
  • N-PDU flag
M
  • Version - 1
  • PT - GTP (1)
  • Spare bit- 0
  • E - 0
  • S - 1
  • PN - 0
  • Version - Determines the version of the GTP protocol.
  • Protocol type - Protocol discriminator between GTP (when PT is “1”) and GTP' (when PT is “0”).
  • Extension header - Indicates the presence of a meaningful value of the next extension header.
  • Sequence number - Value of the sequence number is set to zero (0).
  • N-PDU Number - Value of the N-PDU number is set to zero (0).
Message Type M Integer Message type value is 2.
Recovery O Integer Indicates if the peer GSN restarts. The value matches the values of the messages received from GGSN.
TEID M Integer This attribute value is set to zero (0).