RoHC Profile Decompression Configuration Mode Commands

RoHC Profile Decompression Configuration Mode Commands
 
The RoHC Profile Decompression Configuration Mode is used to configure RoHC (Robust Header Compression) Decompressor parameters.
note_smallImportant: The availability of commands, keywords and variables in this mode are dependent on platform type, product version, and installed license(s).
accept-delayed-pkts
Accepts delayed packets
Product
HSGW, PDSN
Privilege
Administrator
Syntax
[ default ] accept-delayed-pkts
default
Returns the command to its default value of disabled.
Usage
This command helps reduce packet loss during context repair.
Example
Use the following command to enable the system to accept delayed packets:
accept-delayed-pkts
context-timeout
Ensures that no expired contexts are used for data compression.
Product
HSGW, PDSN
Privilege
Administrator
Syntax
context-timeout seconds
default context-timeout
default
Returns the command to its default value.
seconds
Specifies the context timeout value (in seconds) as an integer from 0 through 100.
Default: 20
Usage
The RoHC stack should periodically clean up expired contexts and release memory in case there is no data activity for the call on this context. The context cleanup period is internally calculated to be set to half of the value of the context-timeout value. This will ensure that no expired contexts are used for data compression.
Example
The following command sets the context-timeout parameter to 30 seconds:
context-timeout 30
crc-errors-fo
Sets the limits for when a NACK message is sent while in the FO (First Order) state. A NACK is sent whenever CRC errors are detected within a specified number of packets.
Product
HSGW, PDSN
Privilege
Administrator
Syntax
crc-errors-fo-k num_errors
crc-errors-fo-n num_packts
default crc-errors-fo-k
default crc-errors-fo-n
default
Returns the command to its default value.
crc-errors-fo-k num_errors
Specifies the number of received packets that trigger the sending of a NACK as an integer from 1 through 10.
Default: 1
note_smallImportant: num_errors must be less than or equal to the value specified with the crc-errors-fo-n command.
crc-errors-fo-n num_packts
Specifies the number of packets to check for CRC errors as an integer from 1 through 10.
Default: 1
Usage
Use this command to set the parameters that trigger sending a NACK message when in the FO state.
Example
To configure a NACK to be sent when 4 out of the last 10 packets have CRC errors when in the FO state, use the following commands:
crc-errors-fo-k 4
crc-errors-fo-n 10
crc-errors-so
Sets the limits for when a NACK message is sent while in the SO (Second Order) state. A NACK is sent whenever CRC errors are detected within a specified number of packets.
Product
HSGW, PDSN
Privilege
Administrator
Syntax
crc-errors-so-k num_errors
crc-errors-so-n num_packets
default crc-errors-so-k
default crc-errors-so-n
default
Returns the command to its default value.
crc-errors-so-k num_errors
Specifies the number of received packets that trigger the sending of a NACK as an integer from 0 through 10.
Default: 1
note_smallImportant: num_errors must be less than or equal to the value specified with the crc-errors-so-n command.
crc-errors-so-n num_packets
Specifies the number of packets to check for CRC errors as an integer from 1 through 10.
Default: 1
Usage
Use this command to set the parameters that trigger sending a NACK message when in the SO state.
Example
To configure a NACK to be sent when 4 out of the last 10 packets have CRC errors when in the SO state, use the following commands:
crc-errors-so-k 4
crc-errors-so-n 10
end
Exits the current configuration mode and returns to the Exec mode.
Product
All
Privilege
Security Administrator, Administrator
Syntax
end
Usage
Use this command to return to the Exec mode.
exit
Exits the current mode and returns to the parent configuration mode.
Product
All
Privilege
Security Administrator, Administrator
Syntax
exit
Usage
Use this command to return to the parent configuration mode.
nack-limit
Sets the number of unsuccessful decompressions allowed before a NACK is sent.
Product
HSGW, PDSN
Privilege
Administrator
Syntax
nack-limit limit
default nack-limit
default
Returns the command to its default value.
limit
Specifies the number of unsuccessful decompressions allowed as an integer from 0 through 20.
Default: 0
Usage
Use this command to set the maximum number of unsuccessful decompressions before a NACK message is sent.
Example
The following command sets the number of unsuccessful decompressions allowed to 10:
nack-limit 10
optimistic-mode-ack
When this command is enabled and a type 2 IR-DYN packet is successfully decompressed, an optional ACK is sent in U-mode.
Product
HSGW, PDSN
Privilege
Administrator
Syntax
[ default | no ] optimistic-mode-ack
default
Returns the command to its default value of enabled.
no
Disables the sending of the optional ACK.
Usage
Use this command to enable and disable the sending of an optional ACK in U-mode when a type 2 IR-DYN packet is successfully decompressed.
Example
To enable the sending of the optional ACK, enter the following command:
optimistic-mode-ack
To disable the sending of the optional ACK, enter the following command:
no optimistic-mode-ack
optimistic-mode-ack-limit
Sets the number of packets for which to send ACKs.
Product
HSGW, PDSN
Privilege
Administrator
Syntax
optimistic-mode-ack-limit num_pkts
default optimistic-mode-ack-limit
default
Returns the command to its default value.
num_pkts
Specifies the number of packets for which to send ACKs as an integer from 0 through 20.
Default: 3
Usage
Use this command to set the number of packets to send the optional ACK for when a type 2 IR-DYN packet is successfully decompressed.
Example
Enter the following command to set the number of packets to send and ACK for to 6:
optimistic-mode-ack-limit 6
Use the following command to set the number of packets to send an ACK for back to the default of 3:
default optimistic-mode-ack-limit
piggyback-wait-time
Specifies the time in milliseconds to wait for a feedback packet to be picked up as piggybacked feedback by the associated compressor.
Product
HSGW, PDSN
Privilege
Administrator
Syntax
piggyback-wait-time m_secs
default piggyback-wait-time
default
Returns the command to its default value.
m_secs
Specifies the time (in milliseconds) to wait for a feedback packet to be picked up as an integer value from 0 through 1000.
Default: 80
Usage
Use this command to set the time in milliseconds to wait for a feedback packet to be picked up as piggybacked feedback by the associated compressor.
Example
The following command sets the wait time to 120 ms:
piggyback-wait-time 120
preferred-feedback-mode
Specifies the preferred feedback mode to use between the compressor and the decompressor
Product
HSGW, PDSN
Privilege
Administrator
Syntax
preferred-feedback-mode { bidirectional-optimistic | bidirectional-reliable | unidirectional }
default preferred-feedback-mode
default
Returns the command to its default setting of bidirectional-optimistic.
bidirectional-optimistic
This mode is similar to the Unidirectional mode, with the exception of a feedback channel used to send error recovery requests from the decompressor to compressor.
This is the default mode.
bidirectional-reliable
Reliable mode makes extensive use of a feedback channel to avoid packet loss from context invalidation. A secure reference model is used instead of the optimistic approach used in the other modes. With the secure reference model, the confidence of the compressor depends on acknowledgements from the decompressor for every context updating packet.
Periodically the compressor sends context updating packets repeatedly until an acknowledgement is received from the decompressor.
unidirectional
Packets are sent in only one direction, from the compressor to the decompressor.
Usage
Use this command to specify the preferred feedback method to use between the compressor and the decompressor for the current RoHC profile.
Example
Use the following command to set the preferred feedback mode to bidirectional-reliable:
preferred-feedback-mode bidirectional-reliable
rtp-sn-p
Specifies the value of p in RTP SN (RTP Sequence Number) calculation. Least Significant Bits (LSB) encoding is used for header fields whose values are usually subject to small changes. With LSB encoding, the k least significant bits of the field value are transmitted instead of the original field value, where k is a positive integer. After receiving k bits, the decompressor derives the original value using a previously received value as reference (v_ref). The scheme is guaranteed to be correct if the compressor and the decompressor each use interpretation intervals as follows:
•
In which the original value resides
•
And in which the original value is the only value that has the exact same k least significant bits as those transmitted.
The interpretation interval can be described as a function:
f(v_ref, k). Let f(v_ref, k) = [v_ref - p, v_ref + (2^k - 1) - p]
Where p is an integer.
Product
HSGW, PDSN
Privilege
Administrator
Syntax
rtp-sn-p value
default rtp-sn-p
default
Returns the command to its default value.
value
Specifies the number the value of p in the RTP SN calculation as an integer from 0 through 999.
Usage
Use this command to set the value to use for p when performing the RTP SN calculation.
Example
The following command sets the RTP Sequence Number integer “p” value to 100:
rtp-sn-p 100
rtp-sn-p-override
Allows an override of p in RTP SN calculation. This is disabled by default.
Product
HSGW, PDSN
Privilege
Administrator
Syntax
[ default | no ] rtp-sn-p-override
default
Returns the command to its default value of disabled.
no
Disables overriding p in RTP SN calculation.
Usage
Use this command to allow an override of p in RTP SN calculations.
Example
The following command enables the override of p in the RTP SN calculation:
rtp-sn-p-override
sliding-window-ts
Computes jitter as described in RFC 3095,[4.5.4]
Product
HSGW, PDSN
Privilege
Administrator
Syntax
sliding-window-ts size
default sliding-window-ts
default
Returns the command to its default value of 4.
size
Sets the size of the sliding window. size must be an integer from 1 through 1000.
Default: 4
Usage
Use this command to set the size of the sliding window used to compute jitter for the current RoHC profile.
Example
The following command sets the sliding window size to 500:
sliding-window-ts 500
use-clock-option
Controls usage of the RoHC clock option. The clock option informs the compressor of the clock resolution of the decompressor. This allows the compressor to estimate the jitter introduced by the clock of the decompressor when doing timer-based compression of the RTP timestamp.
Product
HSGW, PDSN
Privilege
Administrator
Syntax
[ default | no ] use-clock-option
default
Returns the command to its default value of enabled.
no
Disables use of the RoHC clock option.
Usage
Use this command to enable and disable the use of the RoHC clock option.
Example
The following command enables RoHC clock option usage:
use-clock-option
The following command disables RoHC clock option usage:
no use-clock-option
use-crc-option
Controls usage of the RoHC cyclic redundancy check (CRC) option. The CRC option contains an 8-bit CRC computed over the entire feedback payload, without the packet type and code octet, but including any CID fields,
Product
HSGW, PDSN
Product
Administrator
Syntax
[ default | no ] use-crc-option
default
Returns the command to its default value of enabled.
no
Disables use of the CRC option.
Usage
Use this command to enable and disable the use of the RoHC CRC option.
Example
The following command enables RoHC CRC option usage:
use-crc-option
The following command disables RoHC CRC option usage:
no use-crc-option
use-feedback
Controls use of the feedback channel. A feedback channel sends error recovery requests and (optionally) acknowledgments of significant context updates from the decompressor to the compressor.
Product
HSGW, PDSN
Privilege
Security Administrator, Administrator
Syntax
[ default | no ] use-feedback
default
Returns the command to its default value of disabled.
no
Disables use of the feedback channel.
Usage
Use this command to enable and disable the use of the RoHC feedback channel.
Example
The following command enables RoHC feedback channel usage:
use-feedback
The following command disables RoHC feedback channel usage:
no use-feedback
use-jitter-option
Controls usage of RoHC jitter option. The jitter option allows the decompressor to report the maximum jitter it has observed
Product
HSGW, PDSN
Privilege
Administrator
Syntax
[ default | no ] use-jitter-option
default
Returns the command to its default value of enabled.
no
Disables use of the jitter option.
Usage
Use this command to enable and disable the use of the RoHC jitter option.
Example
The following command enables RoHC jitter option usage:
use-jitter-option
The following command disables RoHC jitter option usage:
no use-jitter-option
use-reject-option
Controls usage of RoHC reject option. The reject option informs the compressor that the decompressor does not have sufficient resources to handle the flow.
Product
HSGW, PDSN
Privilege
Administrator
Syntax
[ default | no ] use-reject-option
default
Returns the command to its default value of disabled.
no
Disables use of the reject option.
Usage
Use this command to enable and disable the use of the RoHC reject option.
Example
The following command enables RoHC reject option usage:
use-reject-option
The following command disables RoHC reject option usage:
no use-reject-option
use-sn-not-valid-option
Controls usage of the RoHC SN not valid option. The sn-not-valid option indicates that the SN of the feedback is not valid. A compressor must not use the SN of the feedback to find the corresponding sent header when this option is present.
Product
HSGW, PDSN
Privilege
Administrator
Syntax
[ default | no ] use-sn-not-valid-option
default
Returns the command to its default value of enabled.
no
Disables use of the sn-not-valid option.
Usage
Use this command to enable and disable the use of the RoHC sn not valid option.
Example
The following command enables RoHC sn not valid option usage:
use-sn-not-valid-option
The following command disables RoHC sn not valid option usage:
no use-sn-not-valid-option
use-sn-option
Controls usage of RoHC sn option. The sn option provides eight additional bits of SN (Sequence Number, usually the RTP Sequence Number.)
Product
HSGW, PDSN
Privilege
Administrator
Syntax
[ default | no ] use-sn-option
default
Returns the command to its default value of enabled.
no
Disables use of the SN option.
Usage
Use this command to enable and disable the use of the RoHC SN option.
Example
The following command enables RoHC SN option usage:
use-sn-option
The following command disables RoHC SN option usage:
no use-sn-option
 
 
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