3Com MSR 50, MSR 30 X25 packet-size, # Set the modulo on the X.25 interface Serial 2/0 to, 451

451

n

Example

■The packet numbering mode on the pair of DTE and DCE must be the same

■You need to run the shutdown and undo shutdown commands on the interface to apply the new configuration.

■The packet numbering mode of X.25 Layer 3 is different from the frame numbering mode of LAPB (Layer 2 in X.25). When modulo 128 is applied to the DTE/DCE interface with high throughput, it improves only the efficiency of local DTE/DCE interface (point-to-point efficiency) for LAPB; while for Layer 3 in X.25, it improves the efficiency of the two communicating DTE peers (or peer-to-peer efficiency).

# Set the modulo on the X.25 interface Serial 2/0 to 128.

<Sysname> system-view

[Sysname] interface serial 2/0

[Sysname-Serial2/0] x25 modulo 128

x25 packet-size

Syntax x25 packet-sizeinput-packet output-packet

undo x25 packet-size

View Interface view

Parameter input-packet: Maximum input packet length in bytes, ranging from 16 (inclusive) to 4096 (inclusive) and must be the integer power of 2.

output-packet: Maximum output packet length in bytes, its value ranges from 16 (inclusive) to 4096 (inclusive) and must be the integer power of 2.

Description Use the x25 packet-sizecommand to set the maximum input and output packet lengths of X.25 interface.

Use the undo x25 packet-sizecommand to restore their default values.

By default, the maximum input packet length is 128 bytes, and the maximum output packet length is 128 bytes.

Normally, an X.25 packet-switching network has a limitation of the transmission packet size, and the maximum size of a data packet sent by the DTE shall not exceed this size (otherwise it will trigger the reset of the VC). In this way, the DTE devices at sending end and receiving end are required to have datagram fragmentation and reassembly functions. The DTE device at sending end fragments the datagram with a length exceeding the maximum transmission packet length based on the maximum transmission packet length, and sets M bit in other fragments except the final fragment. After receiving these fragments, the DTE at receiving end will reassemble them to a datagram and submit it to the upper-layer protocol based on the M bit. Consult access ISP about this maximum receiving packet length.