Configuring additional parameters for X.25 datagram transmission
X.25 allows the addition of some characteristics, including a series of optional user facilities provisioned in ITU-T Recommendation X.25, for the sake of improving performance and broadening application ranges.
This section describes how to configure such additional features, including the options in the commands x25 map and x25 pvc. Select and configure these additional features according to the X.25 network structure, and the services provided by the service provider.
Complete the following tasks to configure additional parameters for X.25 datagram transmission:
Task | Remarks |
|---|---|
Optional. | |
Setting the maximum number of SVCs that can be associated with one address mapping | Optional. |
Optional. | |
Optional. | |
Setting the queue length for all the virtual circuits on an interface | Optional. |
Optional. | |
Optional. |
Setting the maximum SVC idle interval
For the sake of cost saving, specify an SVC idle time on the expiration of which the SVC will be disconnected. Enabling this feature will not affect the data transmission, because the SVC can be set up again if new packets are waiting for transmission.
To set the maximum SVC idle interval:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter interface view. | interface interface-type interface-number | N/A |
3. Set the maximum idle interval for all the SVCs on the interface. | x25 timer idle minutes | Optional. 0 minutes by default, where no SVC cleared automatically. |
4. Set the maximum idle interval for an SVC associated with an address mapping. | x25 map protocol-type protocol-address x121-address x.121-address idle-timer minutes | Optional. No mapping is created by default. If created, the value defaults to 0 minutes, where no SVC cleared automatically. |
Setting the maximum number of SVCs that can be associated with one address mapping
You can specify the maximum number of SVCs allowed to set up for one address mapping. By default, an X.25 address mapping can only be associated with one virtual circuit. In case of busy traffic and slow line speed, increase this number appropriately to reduce data loss. Up to eight SVCs can be associated with an X.25 address mapping.
To set the maximum number of SVCs that can be associated to one address mapping:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter interface view. | interface interface-type interface-number | N/A |
3. Set the maximum number of SVCs that can be associated to the same address mapping. |
| Optional. The count defaults to 1. |
Setting the packet acknowledgement threshold
By setting the packet acknowledgement threshold (also called "receive-threshold"), you enable the receiving router to send acknowledgement packets before the input window gets full.
According to the X.25 protocol, the receiver sends an acknowledgement when the input window (set with the window-size input-window-size command) gets full. If the delay on your X.25 network is intolerable, set the packet acknowledgement threshold to enable the receiver sends acknowledgement before the input window gets full.
Set the acknowledgement threshold in the range of 0 to the input window size:
If it is set to 1, the receiver acknowledges every packet.
If it is set to 0 or the input window size, the receiver acknowledges packets only when the input window gets full.
To set the packet acknowledgement threshold:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter interface view. | interface interface-type interface-number | N/A |
3. Set the packet acknowledgement threshold. | x25 receive-threshold count | Optional. By default, the threshold is 0. The device acknowledges incoming packets when the input window gets full. |
For information about input window size, see "Traffic control parameters."
Configuring X.25 user facilities
X.25 stipulates various user facilities and you can select and configure them. These configurations can be modified in two ways:
X.25 interface-based configuration (by using the x25 call-facility command)
address-mapping-based configuration (by using the x25 map command)
The configuration based on X.25 interface takes effect in every call originating from this X.25 interface, and the configuration based on address mapping takes effect only in the calls originating from this address mapping. If both configurations are made, the configuration based on address mapping takes priority.
X.25 interface-based configuration
To configure X.25 user facility on an X.25 interface basis:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Define a Recognized Operating Agency (ROA) list. | x25 roa-list roa-name roa-id&<1-10> | Optional. Not defined by default. |
3. Enter interface view. | interface interface-type interface-number | N/A |
4. Specify the Closed User Group (CUG) number. | x25 call-facility closed-user-group number | Optional. Not specified by default. |
5. Perform max packet negotiation when initiating a call. | x25 call-facility packet-size input-packet output-packet | Optional. Not configured by default. |
6. Perform window size negotiation when initiating a call. | x25 call-facility window-size input-window-size output-window-size | Optional. Not configured by default. |
7. Request reverse charging when initiating a call. | x25 call-facility reverse-charge-request | Optional. Not configured by default. |
8. Receive calls with reverse charging requests. | x25 reverse-charge-accept | Optional. Not configured by default. |
9. Request throughput-level negotiation when initiating a call. | x25 call-facility threshold in out | Optional. Not configured by default. |
10. Carry transmission delay request when initiating a call. | x25 call-facility send-delay milliseconds | Optional. Not configured by default. |
11. Specify the ROA. | x25 call-facility roa-list name | Optional. Not configured by default. |
Address mapping-based configuration
To configure X.25 user facility on an address mapping basis:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Define an ROA list. | x25 roa-list roa-name roa-id&<1-10> | Optional. Not defined by default. |
3. Enter interface view. | interface interface-type interface-number | N/A |
4. Specify the CUG number. | x25 map protocol-type protocol-address x121-address x.121-address closed-user-group number | Optional. Not specified by default. |
5. Perform max packet negotiation when initiating a call. | x25 map protocol-type protocol-address x121-address x.121-address packet-size input-packet output-packet | Optional. Not configured by default. |
6. Perform window size negotiation when initiating a call. | x25 map protocol-type protocol-address x121-address x.121-address window-size input-window-size output-window-size | Optional. Not configured by default. |
7. Request reverse charging when initiating a call. | x25 map protocol-type protocol-address x121-address x.121-address reverse-charge-request | Optional. Not configured by default. |
8. Receive calls with reverse charging requests. | x25 map protocol-type protocol-address x121-address x.121-address reverse-charge-accept | Optional. Not configured by default. |
9. Request throughput-level negotiation when initiating a call. | x25 map protocol-type protocol-address x121-address x.121-address threshold in out | Optional. Not configured by default. |
10. Carry transmission delay request when initiating a call. | x25 map protocol-type protocol-address x121-address x.121-address send-delay milliseconds | Optional. Not configured by default. |
11. Specify the ROA. | x25 map protocol-type protocol-address x121-address x.121-address roa-list name | Optional. Not configured by default. |
For CUG configuration, see "Configuring X.25 closed user group."
Setting the queue length for all the virtual circuits on an interface
You can specify the sending and receiving queue lengths of virtual circuit for X.25 to adapt to different network environments. The default queue length can contain 200 packets, but you can increase the number for the sake of preventing accidental packet loss in case of large traffic size or low X.25 network transmission rate.
To set the queue length for all the virtual circuits on an interface:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter interface view. | interface interface-type interface-number | N/A |
3. Set the queue length of X.25 virtual circuit. | x25 queue-length queue-size | Optional. The default setting is 200. |
Enabling the sending of broadcast packets through X.25
Internetworking protocols must send some broadcast datagrams for specific purposes. On the broadcasting physical networks (such as Ethernet), such requirements are naturally supported.
To realize broadcasting in non-broadcasting networks like X.25, determine whether to copy and send a broadcast to a destination. For example, you must enable X.25 to send broadcast datagrams so broadcast-based application layer routing protocols can exchange route information on an X.25 network.
You can enable a virtual circuit to send broadcasting datagrams, regardless of whether it is an SVC or PVC.
To enable the sending of broadcast packets through X.25:
Step | Command |
|---|---|
1. Enter system view. | system-view |
2. Enter interface view. | interface interface-type interface-number |
3. Enable to send broadcasting packets to the peer of the SVC associated with this address mapping. | x25 map protocol-type protocol-address x121-address x.121-address broadcast |
4. Enable to send broadcasting packets to the peer of this PVC. | x25 pvc pvc-number protocol-type protocol-address x121-address x.121-address broadcast |
Restricting the use of address mapping
Before a destination is called, this destination must be found in the address mapping table. Before a call is received, the source of this call must also be found in the address mapping table. However, in some cases, some address mappings are used for only outgoing calls, and others are used for only incoming calls.
To restrict the use of an address mapping:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter interface view. | interface interface-type interface-number | N/A |
3. Disable initiating calls using an address mapping. | x25 map protocol-type protocol-address x121-address x.121-address no-callout | N/A |
4. Disable accepting calls using an address map. | x25 map protocol-type protocol-address x121-address x.121-address no-callin | N/A |