Configures the timers that control the data flow for the logical link
control (LLC) sub-layer.
Important
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This command may be repeated as often as necessary to define the
needed timers.
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Privilege
Security Administrator, Administrator
Mode
Exec > Global Configuration > Context Configuration > GPRS
Service Configuration
configure > context
context_name
> gprs-service
service_name
Entering the above command sequence results in the following prompt:
[context_name]host_name(config-gprs-service)#
Syntax
llc { iov-ui-in-xid-reset | n201u-max { sapi11 pkt-size | sapi3 pkt-size | sapi5 pkt-size | sapi9 pkt-size } | nu-overflow-detection high-watermark high_num low-watermark low_num increment-oc| pdu-lifetime secs | random-value-in-iov-ui [ negotiation-failure-action { fallback-to-default-iovui | reject } ] | reset-vur | t200 sapi1 time | t200 [ sapi11 time | sapi3 time | sapi5 time | sapi7 time | sapi9 time ] | uplink-pdu-len-validation }
default llc { iov-ui-in-xid-reset | n201u-max { sapi11 | sapi3 | sapi5 | sapi9 } | nu-overflow-detection | pdu-lifetime | random-value-in-iov-ui | reset-vur | T200 [ sapi1 | sapi11 | sapi3 | sapi5 | sapi7 | sapi9 ] | uplink-pdu-len-validation }
no llc { iov-ui-in-xid-reset | nu-overflow-detection | random-value-in-iov-ui | reset-vur | uplink-pdu-len-validation }
default
Resets the configuration parameter to the default values.
no
Disables a defined configuration parameter and returns to the SGSN
default.
iov-ui-in-xid-reset
This keyword makes it possible for the operator to configure whether
or not to send IOV-UI in an XID-RESET. This is useful when the MS is not setup
to accept IOV-UI (for example, MS sends Attach/RAU Requests with cksn=7) and
including IOV-UI in the XID-Reset would result in Attach/RAU failure.
Default: Enabled
n201u-max sapi
n
pkt_size
This keyword sets the maximum number of octets, per service access
point identifier (SAPI), for the downlink data packets. This is the upper limit
that the SGSN will negotiate with the subscriber for packets sent from the SGSN
to the BSC.
sapi
n : Command must identify one
of the following SAPI: sapi11, sapi3, sapi5, or sapi9.
pkt_size : Must be an integer from 140 to
1520. Default size is 1520 octets.
nu-overflow-detection high-watermark
high_num
low-watermark
low_num
increment-oc
Enables/disables overflow detection for the N(u) counter and setting
overflow high/low thresholds facilitates ciphering synchronization between the
MS and SGSN.
high_num : Enter an integer between 1 and
511.
low_num : Enter an integer between 0 and 510.
If the expected value of nu(Vur) is greater than or equal to the
configured high-watermark, and the received nu(LFN) is less than or equal to
the configured low-watermark, the SGSN increments the overflow counter (VurOC).
The recommended overflow settings are as follows:llc
nu-overflow-detection high-watermark 496 low-watermark 15
increment-oc While expecting a packet with 496 < nu < 511
and a packet with 0 < nu < 15 is received, overflow is detected and VurOC
is incremented.
pdu-lifetime
secs
Defines LLC layer PDU lifetime at the BSC. .
secs must be an integer from 0 to 90.
Default: 6
random-value-in-iov-ui [ negotiation-failure-action {
fallback-to-default-iovui | reject } ]
Including this keyword enables the SGSN to negotiate the sending of a
random value for the IOV-UI in the XID Request sent to the MS. If this keyword
is not included, then by default the SGSN sends a zero (0) as the value of the
IOV-UI in the XID message.
Including
default in a command with the
negotiation-failure-action keyword resets the
SGSN configuration so that all calls are rejected whenever the decipering fails
due to failure of the XID negotiation for random IOV-UI
If the
negotiation-failure-action fallback-to-default-iovui
option is included in the configuration, then the SGSN
will fall back to unencrypted mode whenever tthe XID negotiation for random
IOV-UI negotiation fails..
If the
negotiation-failure-action reject
option is included in the configuration to return the
SGSN to the default functionality and reject all calls when random IOV-UI
negotition fails. This option is typically used only if the
negotiation-failure-action fallback-to-default-iovui
option has previously been part of the configuration.
The
reject option conditionally causes the SGSN
to reject calls , for example, when XID for random IOV-UI negotiation failure
occurs during intra-RAU or standalone authentication for SMS, the SGSN moves
the subscriber to STANDBY and marks the XID negotiation as a failure.
OR
Despite the
reject configuration, the SGSN may respond to
XID negotiation failure in one of the following mnners according to associated
circumstances:
- Initiates XID for new random IOV-UI negotiation:
- with the MS is in STANDBY state, any uplink packet (in either
ciphered or unciphered mode, except Attach / Intra-RAU) from the MS which
results in CELL-UPDATE, READY TIMER START and RADIO STATUS READY causes an
event indication to the application.
- Initiates Detach:
- with the MS is in STANDBY state, any uplink activity causes the
SGSN to initiate a new XID exchange, which if it fails or aborts due to the
reception of SUSPEND, RADIO-STATUS and READY-TIMER expiry, results in the SGSN
initiating Detach.
- when PAGING is ongoing , any Page response from the MS results
in the SGSN initiating Detach.
- during OLD_SGSN ISRAU, when any uplink data comes before T3
tunnel timer expiry then the SGSN initiates Detach.
- Handles Messages:
- Attach and intra-RAU (from both local and non-local TLLI or
from both the same and different RA) will be processed in any state.
- Moves to STANDBY state:
- MS is moved to STAND-BY state if the XID exchange failed due to
any of the following cases suspend, radio status, BVC block, BVC reset, ready
timer expiry, no response received for XID exchange during INTRA-RAU/Standalone
Authentication for SMS.
- XID is ongoing in READY state and if the MS moves to either 3G
or to the peer-SGSN then the subscriber is moved to STANDBY state.
reset-vur
Enables/disables the mechanism to reset the Vur value maintained at
LLC if the intra RAU request is received with N(U) = 0
Default: Disabled
T200 sapi1
time
Sets the retransmission timer (in seconds) for sapi1.
time must be an integer of 1 to 10.
Default: 5
T200 sapi11
time
Sets the retransmission timer (in seconds) for sapi11.
time must be an integer of 1 to 50.
Default: 40
T200 sapi3
time
Sets the retransmission timer (in seconds) for sapi3.
time must be an integer of 1 to 10.
Default: 5
T200 sapi5
time
Sets the retransmission timer (in seconds) for sapi5.
time must be an integer of 1 to 20.
Default: 10
T200 sapi7
time
Sets the retransmission timer (in seconds) for sapi7.
time must be an integer of 1 to 40.
Default: 20
T200 sapi9
time
Sets the retransmission timer (in seconds) for sapi9.
time must be an integer of 1 to 40.
Default: 20
uplink-pdu-len-validation
This feature enables validation of the size of the uplink LLC packets.
With validation enabled, the SGSN will drop any uplinked packets that are
larger than the negotiated limit.
If the
no form of the command is used, then this
feature is disabled. The SGSN will be more flexible with uplink packet sizes.
So if the SGSN and MS have a mismatch and the MS sends packets that are larger
than expected, then the SGSN will not drop the packets.
Default: Enabled.
Usage Guidelines
Use the command repeatedly to configure additional timers and features
for the LLC sub-layer.
Example
Set the T200 retransmission timer to timeout at 12 seconds for SAPI5:
llc t200 sapi5 12
Use the following command to instruct the SGSN to ignore the N201_U
packet size limits for uplink packets from an MS:
no uplink-pdu-len-validation
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