Configuring X.25 8-17Local Charging Preventionprevents calls (if Y) from being charged to this port. Incoming calls from the networkwith Reverse Charging specified will be rejected; outgoing calls will have ReverseCharging inserted if it is not already in the call packet.Reverse Charge Acceptanceauthorizes transmission of incoming calls that request the X.25 Reverse Chargingfacility. If N is selected for this parameter and a call requests Reverse Charging, thecall will not be transmitted.Fast Select Acceptanceauthorizes transmission of incoming calls that request the X.25 Fast Select facility.Incoming Calls Barredis an X.25 facility that prevents transmission of incoming calls to this port.Outgoing Calls Barredis an X.25 facility that prevents transmission of outgoing calls from this port.Maximum Packet Sizeis the maximum data packet size that will be allowed to pass through this port. Apacket size included in a call setup packet will be used, as long as it is smaller than themaximum specified here.Default Packet Sizewill be assigned to an incoming call setup packet if the packet does not include apacket size. A packet size of 512 bytes is imposed on all protocols except X.25between the PAD port and the logical port. The Default Packet Size is used for trans-mission out the logical port. (X.25 traffic uses the Maximum Packet Size configured onthe X.25 port.)Multiple packet sizes (e.g., multipoint SDLC-to-QLLC) require either mul-tiple logical ports or X.25 address translation (see page 8-27) (which allowsmodification of facilities in Call Request packets).Maximum Window Sizeis the maximum number of sequentially numbered I-frames that can be waiting foracknowledgment by the (end-to-end) destination device. If this number is exceeded,no frames will be transmitted until an acknowledgment is received.There is also a local level-3 window for X.25 traffic. This window willalways be in effect unless the D-bit is set at the attached X.25 device.Default Window Sizewill be assigned to an incoming call setup packet if the packet does not include awindow size.Maximum Throughput Classspecifies the default throughput class that will be inserted into a Call Request packetif Throughput Class Negotiation is not enabled or if a throughput class is not requestedin the Call Request. This value should not be higher than the line speed specified forthe physical port.
