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This chapter describes the Link Access Procedure, Balanced (LAPB) Service parameters. 3Com's implementation is based on the CCITT X.25 Level 2 specification; see this document for more information. Table 78 lists the LAPB Service parameters and commands.
Syntax
SHow [!<path> | !*] -LAPB CONFiguration
SHowDefault [!<path> | !*] -LAPB CONFiguration
No default
The CONFiguration parameter displays the LAPB parameter values on a path-by-path basis.
Syntax
SETDefault !<path> -LAPB CONTrol = Enable | Disable
SHow [!<path> | !*] -LAPB CONTrol
SHowDefault [!<path> | !*] -LAPB CONTrol
Disable
The CONTrol parameter enables or disables the LAPB Service. For parameter changes to take effect immediately, you must toggle the path by enabling it. When you enable the path, Enterprise OS software first disables it and then enables it.
The SHow command displays CONTrol settings for a particular path. If no path is specified, the CONTrol values for all paths are shown.
Values
|
Enable |
Enables LAPB over the specified path. |
|
Disable |
Disables LAPB over the specified path. |
Syntax
SETDefault !<path> -LAPB FrameSeq = Basic | Extended
SHow [!<path> | !*] -LAPB FrameSeq
SHowDefault [!<path> | !*] -LAPB FrameSeq
Basic
The FrameSeq parameter specifies basic or extended sequencing.
Values
|
Basic |
Enables numbered frames to range from 0-7. |
|
Extended |
Enables numbered frames to range from 0-127. |
Syntax
SETDefault !<path> -LAPB InterfaceType = DTE | DCE
SHow [!<path> | !*] -LAPB InterfaceType
SHowDefault [!<path> | !*] -LAPB InterfaceType
DTE
The InterfaceType parameter specifies the interface type of the path. Most public data networks (PDNs) function as data communications equipment (DCE), so the default value of this parameter is acceptable. If you want to configure the bridge/router in a private network, one device must function as the DCE and the other as the data terminal equipment (DTE).
Values
Syntax
SETDefault !<path> -LAPB N2 = <1-255>
SHow [!<path> | !*] -LAPB N2
SHowDefault [!<path> | !*] -LAPB N2
10
The N2 parameter specifies the maximum number of times a frame is sent after a time-out.
Syntax
SETDefault !<path> -LAPB T1 = <100-1000000>
SHow [!<path> | !*] -LAPB T1
SHowDefault [!<path> | !*] -LAPB T1
3000
The T1 parameter specifies the maximum time (in milliseconds) that the LAPB Protocol waits for an acknowledgment once a frame is transmitted. Any value you enter for the T1 parameter is internally divided by 250 milliseconds. As a result, any value you enter less than 250 actually equals zero.
Syntax
SETDefault !<path> -LAPB T3 = <0-1000000>
SHow [!<path> | !*] -LAPB T3
SHowDefault [!<path> | !*] -LAPB T3
0
The T3 parameter specifies the maximum period of line idle time. When this time expires, the link is assumed to be down and LAPB attempts to set up the link again. If the value of this parameter is set to 0, LAPB does not bring the idle link down. Any value you enter for the T3 parameter is internally divided by 250 milliseconds. As a result, any value you enter less than 250 actually equals zero.
Syntax
SETDefault !<path> -LAPB WindowSize = <1-127>
SHow [!<path> | !*] -LAPB WindowSize
SHowDefault [!<path> | !*] -LAPB WindowSize
7
The WindowSize parameter specifies the maximum number of frames LAPB sends without an acknowledgment.