Configure the GPRS Tunneling Protocol Control (GTP-C) settings for the
SGTP service.
Product
eWAG
MME
PDG/TTG
SGSN
Privilege
Security Administrator, Administrator
Mode
Exec > Global Configuration > Context Configuration > SGTP
Service Configuration
configure > context
context_name
> sgtp-service
service_name
Entering the above command sequence results in the following prompt:
[context_name]host_name(config-sgtp-service)#
Syntax
gtpc { bind address ipv4_address | dns-sgsn context context_name | echo-interval interval_seconds | echo-retransmission { exponential-backoff [ [ min-timeout timeout_seconds ] [ smooth-factor smooth_factor ] + ] | timeout timeout_seconds } | guard-interval interval_seconds | ignore response-port-validation | ip qos-dscp dscp_marking | max-retransmissions max_retransmissions | retransmission-timeout timeout_seconds | send { common flags | rab-context | target-identification-preamble } | sync-echo-with-peer }
no gtpc { bind address | dns-sgsn context | echo-interval | send { common-flags | rab-context | target-identification-preamble } | sync-echo-with-peer }
default gtpc { echo-interval | echo-retransmission | guard-interval | ignore response-port-validation | ip qos-dscp | max-retransmissions | retransmission-timeout | send { common-flags | rab-context | target-identification-preamble } | sync-echo-with-peer }
no
Disables the configured GTP-C setting.
default
Resets the specified parameter to its default value.
bind address
ipv4_address
Binds SGTP service to the IP address of the interface.
The bind address for the
gtpc and
gtpu commands should be the same.
ipv4_address must be a standard IPv4
address.
dns-sgsn context
context_name
Identify the context where the DNS client is configured to send the
DNS query to get the peer SGSN address. If nothing is configured, the system
assumes the DNS client is configured in the same context where the SGTP service
is configured.
context_name : Enter a string of 1 to 79
alphanumeric characters to identify the context.
There is a dns-sgsn command option in the call-control profile, which,
if configured, would override the configuration in this SGTP service
configuration.
echo-interval
interval_seconds
Configures the duration between echoes.
seconds Enter an integer from 0 through
3600.
Default: 60
echo-retransmission { exponential-backoff [ [
min-timeout
timeout_seconds
] [ smooth-factor
smooth_factor
] + ] | timeout
timeout_seconds
}
Configures the retransmission parameters for GTP-C echo messages. The
operator can choose to use either an "exponential-backoff" timers or a
"fixed-retransmission" timer:
-
The
exponential-backoff timer uses an
exponential backoff algorithm to better manage the GTP-C path during periods of
network congestion and to perform exponential-backoff echo timing. The
exponential-backoff timer uses a calculated round-trip time (RTT), as well as a
configurable factor or a multiplier to be applied to the RTT statistic.
Different paths can each have a different RTT, so the exponential-backoff timer
can be configured for multiple paths. One or both of the following parameters
can be configured to refine the exponential-backoff timer configuration:
-
min-timeout
timeout_seconds :
Specifies the minimum time period (in seconds) for the exponential-backoff echo
timer. If the RTT multiplied by the smooth factor is less than this minimum
timeout value, then the node uses the value set with this keyword. Range is
1-20. Default is 5.
-
smooth-factor
smooth_factor :
Specifies the multiplier that the exponential-backoff echo timer uses when
calculating the time to wait to send retries, when the gateway has not received
a response from the peer within value defined for the path echo interval. Range
is 1-5. Default is 2.
-
timeout
timeout_seconds :
Configures the number of seconds for the fixed retransmission timeout value for
GTP-C echo messages. Range from 1 to 20. Default is 5.
guard-interval
interval_seconds
Configures the interval (in seconds) for which the SGTP maintains
responses sent to gateway. This optimizes the handling of retransmitted
messages. This value should be configured to be greater than the gateway's
configuration for max-retries multiple by retry-interval.
interval_seconds : Enter an integer from 10
to 3600.
Default: 100
ignore response-port-validation
This keyword instructs the gateway to ignore the response port
validation.
For the gateway to process incoming GTP responses to an
incorrect port, this keyword must be entered, and the same
bind address must be configured for GTPC and
GTPU in the SGTP service.
Default: Disabled. To reset the default for this parameter, you must
enter the following command:
no gtpc ignore response-port-validation .
ip qos-dscp
dscp_marking
Configures the diffserv code point marking to be used per hop behavior
(PHB) when sending GTP-C messages originating from the session manager and
SGTPC manager.
Note that CS (class selector) mode options below are provided to
support backward compatibility with the IP precedence field used by some
network devides. CS maps one-to-one to IP precedence, i.e., CS1 is IP
precedence value 1. If a packet is received from a non-DSCP aware router, that
used IP precedence markings, then the DSCP router can still understand the
encoding as a Class Selector code point.
dscp_marking : Enter one of the following
values:
-
af11: Marks traffic as Assured Forwarding 11 PHB (high
throughput data)
-
af12: Marks traffic as Assured Forwarding 12 PHB (high
throughput data)
-
af13: Marks traffic as Assured Forwarding 13 PHB (high
throughput data)
-
af21: Marks traffic as Assured Forwarding 21 PHB (low
latency data)
-
af22: Marks traffic as Assured Forwarding 22 PHB (low
latency data)
-
af23: Marks traffic as Assured Forwarding 23 PHB (low
latency data)
-
af31: Marks traffic as Assured Forwarding 31 PHB
(multimedia streaming)
-
af32: Marks traffic as Assured Forwarding 32 PHB
(multimedia streaming)
-
af33: Marks traffic as Assured Forwarding 33 PHB
(multimedia streaming)
-
af41: Marks traffic as Assured Forwarding 41 PHB
(multimedia conferencing).
-
af42: Marks traffic as Assured Forwarding 42 PHB
(multimedia conferencing)
-
af43: Marks traffic as Assured Forwarding 43 PHB
(multimedia conferencing)
-
be
: Designates use of Best Effort forwarding PHB. This is the
default value.
-
cs0
: Designates use of class selector mode 0 PHB.
-
cs1
: Designates use of class selector mode 1 PHB.
-
cs2
: Designates use of class selector mode 2 PHB.
-
cs3
: Designates use of class selector mode 3 PHB.
-
cs4
: Designates use of class selector mode 4 PHB.
-
cs5
: Designates use of class selector mode 5 PHB.
-
cs6
: Designates use of class selector mode 6 PHB.
-
cs7
: Designates use of class selector mode 7 PHB.
-
ef : Designates use of Expedited Forwarding PHB
Default:
be (best effort)
max-retransmissions
max_retransmissions
Configures the maximum number of retries for packets.
max_retransmissions : Enter an integer from 0
to 15.
Default: 4
retransmission-timeout
timeout_seconds
Configures the control packet retransmission timeout in GTP, in
seconds.
timeout_seconds : Enter an integer value from
1 through 20.
Default: 5
send { common-flags | rab-context |
target-identification-preamble }
Important
|
Sending of common flags must be enabled to configure dual PDP type
(IPv4v6) addressing with the
dual-address-pdp command in the SGSN global
configuration mode.
|
-
rab-context : This option configures the
SGTP service to include/exclude the radio access bearer (RAB) context IE in
SGSN 'context response' message during Inter-SGSN Routing Area Update
procedure. Default is to send the RAB context IE.
-
target-identification-preamble : This
option configures the SGTP service to include the Target Identification IE
preamble byte in the target-id of Relocation Requests that it sends. By
default, the preamble is not included. In accordance with 3GPP TS 29.060,
v9.2.0, if the preamble is included then multiple optional parameters, such as
Extended RNC ID, are encoded. Extended RNC ID expands the ID range from 4095 to
65535.
In situations of MME interaction with the SGSN during SRNS
procedures via GTPv1, the SGSN can use this Extended RNC ID field to indicate
the Target RNC ID associated with the MME and vice versa.
Default: sending RAB context IE.
sync-echo-with-peer
This keyword is applicable to the SGSN only.
This keyword enables the SGSN to synchronize path management
procedures with the peer after a GTP service restart recovery.
After GTP service recovery, the SGSN restarts the timers for GTP echo
transmission, hence a drift in echo request transmission time (from the
pre-recovery time) can occur causing the SGSN to be out of sync with the peer.
By using this keyword, when the SGSN receives the first Echo Request (GTPC or
GTPU) from the peer after the GTP service restart, in addition to replying with
an ECHO Response, the SGSN transmits an ECHO Request to the peer and the SGSN
restarts the timers associated with the path management procedures. This causes
the path management procedure at SGSN to synchronize with the peer node.
Default: Enabled
Usage Guidelines
Use this command to configure GTP-C settings for the current SGTP
service. Repeat the command as needed to configure all required GTP-C
parameters.
Example
Following command excludes the radio access bearer (RAB) context IE in
the SGSN Context Response message during the inter-SGSN RAU procedure:
no gtpc send rab-context
Configure the SGSN to send
common flags with all GTP-C messages:
gtpc send common-flags
Set the SGSN to use GTPC echo-retransmission with exponential-backoff
and both filters set for default:
gtpc echo-retransmission exponential-backoff