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.

ATM Encapsulation Header Lengths

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:

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:

atmHeader setDefault

Sets to IxTclHal default values for all configuration options.

EXAMPLES

See examples in stream

SEE ALSO

atmPort, stream, streamQueue, streamQueueList