atmHeader
atmHeader - configure ATM header parameters.
SYNOPSIS
atmHeader sub-command options
DESCRIPTION
The atmHeader command is used to configure the ATM header options which are used in streams configured with the stream command. Note that stream get must be called before this command's get sub-command.
Note that different types of ATM encapsulation result in different length headers, as discussed in the following table.
Encapsulation |
Header Length |
---|---|
LLC Snap Routed |
8 |
LLC Bridged Ethernet / 802.3 |
10 |
LLC Bridged Ethernet / 802.3 No FCS |
10 |
LLC Encapsulated PPP |
6 |
VC Muxed PPP |
2 |
VC Muxed Routed |
0 |
VC Muxed Bridged Ethernet / 802.3 |
2 |
VC Muxed Bridged Ethernet / 802.3 No FCS |
2 |
The data portion of the packet normally follows the header, except in the case of the two LLC Bridged Ethernet choices, where 12 octets of MAC address and 2 octets of Ethernet type follow the header. The offsets used in the dataIntegrity, filter, flexibleTimestamp, ip, ipV6Fragment, packetGroup, protocolOffset, qos, tableUdfColumn, tcp, udf, and udp are with respect to the beginning of the AAL5 packet and must be adjusted by hand to account for the header.
The framesize of an ATM packet is set by a combination of the enableCpcsLength and cpcsLength options in this command and the framesize option in the stream command. If enableCpcsLength is set to true, then the ATM frame's size is set from the cpcsLength value only. Otherwise, it is set from the stream's framesize value and the cpcsLength value is calculated from that. Further, the stream getQueue command resets this command's enableCpcsLength option to false. It is important to correctly set the stream's framesize value and this command's enableCpcsLength and cpcsLength options after each stream getQueue command and call atmHeader set before the next stream setQueue command.
STANDARD OPTIONS
aal5Error
May be used to insert a bad AAL5 CRC.
Option |
Value |
Usage |
---|---|---|
aal5NoError |
0 |
(default) No error is inserted |
al5BadCrc |
1 |
Inserts an AAL5 CRC error. |
cellLossPriority
Sets the Cell Loss Priority, also abbreviated as CLPUsed to set the discard priority level of the cell. It indicates whether the cell should be discarded if it encounters extreme congestion as it moves through the network. Values of 0 and 1 are allowed, with 0 having a higher priority than 1. (default = 0)
cpcsLength
If enableCpcsLength is true, then this is used as the length of the CPCS PDU. (default = 28)
enableAutoVpiVci
Selection true | false
If true, the vpi/vci values are forced to 0 and 32. (default = false)
enableCL true | false
Indicates whether congestion has been experienced. (default = false)
enableCpcsLength
true |false
If true, the value of cpcsLength is used as the length of the CPCS PDU. The value of the framesize configured in the stream command is ignored. It is important to note that this value is always set to false by the stream getQueue command. (default = false)
encapsulation
The type of header encapsulation.
Option |
Value |
Usage |
---|---|---|
atmEncapsulationVccMuxIPV4Routed |
101 |
|
atmEncapsulationVccMuxBridgedEthernetFCS |
102 |
|
atmEncapsulationVccMuxBridgedEthernetNoFCS |
103 |
|
atmEncapsulationVccMuxIPV6Routed |
104 |
|
atmEncapsulationVccMuxMPLSRouted |
105 |
|
atmEncapsulationLLCRoutedCLIP |
106 |
(default) |
atmEncapsulationLLCBridgedEthernetFCS |
107 |
|
atmEncapsulationLLCBridgedEthernetNoFCS |
108 |
|
atmEncapsulationLLCPPPoA |
109 |
|
atmEncapsulationVccMuxPPPoA |
110 |
|
atmEncapsulationLLCNLPIDRouted |
111 |
|
genericFlowControl
Generic Flow Control for use in UNI mode device control signalling. Uncontrolled equipment uses a setting of 0000. (default = 0)
header
Read-only. The 5-byte calculated header value.
hecErrors
Indicates the number of HEC errors to insert into the HEC byte. Values of 0 (no errors) through 8 (8 errors) are allowed. (default = 0)
vci
The virtual circuit identifier. (default = 32)
vpi
The virtual path identifier. (default = 0)
COMMANDS
The atmHeader command is invoked with the following sub-commands. If no sub-command is specified, returns a list of all sub-commands available.
atmHeader cget option
Returns the current value of the configuration option given by option. Option may have any of the values accepted by the atmHeader command.
atmHeader config option value
Modify the configuration options of the atmHeader. If no option is specified, returns a list describing all of the available options (see STANDARD OPTIONS) for atmHeader.
atmHeader get chasID cardID portID
Gets the current configuration of the atmHeader for the port. Note that stream get must be called before this command's get sub-command. Call this command before calling atmHeader cget option value to get the value of the configuration option. Specific errors are as follows:
- No connection to a chassis
- Protocol data has not been configured for this port through a stream set or protocol set
atmHeader set chasID cardID portID
Sets the configuration of the atmHeader in IxHAL for the port by reading the configuration option values set by the atmHeader config option value command. Specific errors are as follows:
- No connection to a chassis
- Invalid port number
- Port unavailable or in use
- Configured parameters are not valid for this setting
- ATM is not supported on this port
atmHeader setDefault
Sets to IxTclHal default values for all configuration options.
EXAMPLES
See examples in stream