> RoHC Profile Decompression Configuration Mode Commands
> The RoHC Profile Decompression Configuration Mode is used to configure RoHC (Robust Header Compression) Decompressor parameters.
> Important: 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
> Default: 20 seconds
> The context timeout value in seconds. seconds must be an integer from 0 through 100.
> 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
> This command sets the limits for when a NACK message is sent when in the FO (First Order) state. A NACK is sent when out of a specified number of packets a specified number of them have CRC errors.
> 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
> Default: 1
> The number of received packets within a specified number of received packets that triggers the sending of a NACK. num_errors must be an integer from 1 through 10.
> Important: 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
> Default: 1
> The number of packets to check for CRC errors. num_packts must be an integer from 1 through 10.
> 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
> This command sets the limits for when a NACK message is sent when in the SO (Second Order) state. A NACK is sent when out of a specified number of packets a specified number of them have CRC errors.
> 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
> Default: 1
> The number of received packets within a specified number of received packets that triggers the sending of a NACK. num_errors must be an integer from 0 through 10.
> Important: 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
> Default: 1
> The number of packets to check for CRC errors. num_packets must be an integer from 1 through 10.
> 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
> Returns the CLI prompt to to the Exec mode.
> Product
> HSGW, PDSN
> Privilege
> Administrator
> Syntax end
> Usage
> Change the mode back to the Exec mode.
> exit
> Exits the this configuration mode and returns to the previous mode.
> Product
> HSGW, PDSN
> Privilege
> Administrator
> Syntax exit
> Usage
> Return to the previous 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
> Default: 0
> Specifies the number of unsuccessful decompressions allowed. limit must be an integer from 0 through 20.
> 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 is enabled, if 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
> When enabled, this command sets the number of packets to send ACKs for.
> 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
> Default: 3
> The number of packets to send ACKs for . num_pktsmust be an integer from 0 through 20.
> 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
> 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
> Default: 80ms
> Specifies the time in milliseconds to wait for a feedback packet to be picked up. m_secs must be an integer value from 0 through 1000.
> 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
> Default: bidirectional-optimistic
> Returns the command to its default setting.
> 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.
> 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
> 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
> Default:
> Specifies the number to use for the value of p in the RTP SN calculation. value must be 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
> Allow 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.
> size
> Default: 4
> Set the size of the sliding window. size must be an integer from 1 through 1000.
> 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 RoHC clock option. The clock option informs the compressor of the clock resolution of the decompressor. This is needed to allow 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
> Disable 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 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
> Disable 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
> Disable 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
> Disable 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
> Disable 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
> Disable 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 8 additional bits of SN (Sequence Number. Usually 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
> Disable 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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