Configuring DLSw

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This section includes the following sections:

Minimum DLSw Configuration

To enable DLSw on a router, you must include at least the following statements at the [edit protocols dlsw] hierarchy level:


            
               local-peer peer-address;
               
               promiscuous;

Specify the promiscuous statement to allow the router to accept all incoming peer connections.

Configuring the Remote Peer

You can specify one or more remote peers to initiate a DLSw connection. Configuring the remote peer initiates the connection and also accepts connection from that remote peer only, if promiscuous mode is not configured.

To configure a specific DLSw remote peer, include the remote-peer statement at the [edit protocols dlsw] hierarchy level:


            
               remote-peer peer-address;

You can configure more than one remote peer.

Configuring Load Balancing

When more than one remote peer provides alternative paths to a destination, you can specify preferences among the available routers or enable load balancing for alternatives that have the same lowest cost value. The DLSw router maintains a cache of paired media access control (MAC) address and IP address entries to determine whether an SNA host can reached by means of any of the peers it knows about. There are separate caches for local and remote peers, called the local reachability cache and the remote reachability cache.

To configure DLSw load balancing, include the load-balance statement at the [edit protocols dlsw] hierarchy level:


            
               load-balance circuit-weight;

By default, load balancing is disabled. Load balancing uses the circuit-weight algorithm to make its determinations. This requires that, if there are multiple routes to a destination that share the same lowest cost value, the number of circuits traversing each peer is balanced according to the circuit weight you configure for each peer:

To configure the circuit cost, or how much preference is attached to establishing a circuit using a peer, include the cost statement at the [edit protocols dlsw remote-peer peer-address] hierarchy level:
cost cost;

By default, the cost value is 100. The range is from 0 through 127. The lower the configured cost value, the higher the preference.
To configure the circuit weight, or the extent to which a peer should participate in establishing circuits, include the circuit-weight statement at the [edit protocols dlsw remote-peer peer-address] hierarchy level:
circuit-weight weight;

By default, the circuit-weight value is 1. The range is from 1 through 127. The higher the configured circuit-weight value, the greater the percentage of total circuits established with this remote peer.

Configuring DLSw Timers

You can also configure two timer values that influence how circuits on the DLSw router are established:

Explorer timeout is the maximum time the DLSw router waits for its peers to respond to its explorer requests. To configure a timeout period, include the explorer-wait-time statement at the [edit protocols dlsw] hierarchy level:
explorer-wait-time seconds;

By default, the explorer-wait-time value is 10 seconds. The range is from 5 through 60 seconds.
Reachability cache timeout is the maximum time an entry remains in the reachability cache before it is deleted. To configure a timeout period, include the reachability-cache-timeout statement at the [edit protocols dlsw] hierarchy level:
reachability-cache-timeout seconds;

By default, the reachability-cache-timeout value is 900 seconds. The range is from 0 through 3600 seconds. A lower value helps detect new routes that might have become available during the timeout period.

Configuring the Local Peer

You can specify a local peer from which you will accept connection requests specifically. To configure a DLSw local peer, include the local-peer statement at the [edit protocols dlsw] hierarchy level:


            
               local-peer peer-address;

Examples: Configuring DLSw Peers

Configure the router when it is closer to the client and expects to initiate connections to peers:


            
               dlsw {
               local-peer peer-address;
               
               remote-peer peer-address;
               
               }

Configure the router when it is closer to the server and does not expect to initiate connections:


            
               dlsw {
               local-peer peer-address;
               
               promiscuous;
               }

Configure specific peers and accept incoming connections only from those peers:


            
               dlsw {
               local-peer peer-address;
               
               promiscuous;
               }

Configure so that for some applications you initiate connections, and for other applications you receive connections from other peers:


            
               dlsw {
               local-peer peer-address;
               
               remote-peer peer-address;
               
               promiscuous;
               }

Configuring the Initial Pacing Window

To configure the DLSw initial pacing window size, include the receive-initial-pacing statement at the [edit protocols dlsw] hierarchy level:


            
               receive-initial-pacing number;

Specify the number value to configure the initial value of the receive pacing window size for the sending peer.

Configuring the Idle Timeout

To configure an idle timeout period, include the connection-idle-timeout statement at the [edit protocols dlsw] hierarchy level:


            
               connection-idle-timeout time;

Specify the connection-idle-timeout statement to configure the idle time period after which the connection is torn down.

Configuring the Multicast Address

To configure the multicast address for DLSw, include the multicast-address statement at the [edit protocols dlsw] hierarchy level:


            
               multicast-address address;

Configuring Class of Service

Class of service (CoS) can be used to classify DLSw packets, which are sent to a logical tunnel interface that loops the packets into the Packet Forwarding Engine. The Packet Forwarding Engine classifies and queues the packets based on the configured type-of-service (ToS) value.

To configure CoS for DLSw, include the dlsw-cos statement at the [edit protocols dlsw] hierarchy level:


            
               dlsw-cos {
               
               destination-interface interface-name;
               
               type-of-service number;
               
               }

To enable traffic through a specified destination interface, specify the destination-interface statement. To configure the ToS value, specify the type-of-service statement.

To configure the Differentiated Services code point (DSCP) for DLSw, include the dscp statement at the [edit class-of-service interfaces interface-name unit unit-number classifiers] hierarchy level:

For information on configuring class-of-service properties, see the JUNOS Class of Service Configuration Guide.

Example: Configuring CoS for a DLSw Connection

Configure the lt-0/0/0 interface:


            
               [edit]
               interfaces lt-0/0/0 {
               
                  
                     unit 0 {
                     encapsulation frame-relay;
                     dlci 100;
                     peer-unit 1;
                     family inet;
                     }
                  
               
               
                  
                     unit 1 {
                     encapsulation frame-relay;
                     dlci 100;
                     peer-unit 0;
                     family inet;
                     }
                  
               
               }

Enable the DLSw protocol:


            
               [edit protocols]
               dlsw {
               local-peer 1.1.1.1;
               remote-peer 1.1.1.2;
               
                  
                     dlsw-cos {
                     type-of-service 192;
                     destination-interface lt-0/0/0.0;
                     }
                  
               
               }

Configure the CoS parameters on the lt-0/0/0 interface:


            
               [edit class-of-service]
               classifiers {
               
                  
                     inet-precedence ipPREC {
                     
                        
                           forwarding-class best-effort {
                           loss-priority low code-points 000;
                           loss-priority high code-points 001;
                           }
                        
                     
                     
                        
                           forwarding-class expedited-forwarding {
                           loss-priority low code-points 010;
                           loss-priority high code-points 011;
                           }
                        
                     
                     
                        
                           forwarding-class assured-forwarding {
                           loss-priority low code-points 100;
                           loss-priority high code-points 101;
                           }
                        
                     
                     
                        
                           forwarding-class network-control {
                           loss-priority low code-points 110;
                           loss-priority high code-points 111;
                           }
                        
                     
                     }
                  
               
               }
               interfaces {
               
                  
                     lt-0/0/0 {
                     
                        
                           unit 1 {
                           
                              
                                 classifiers {
                                 dscp default;
                                 }
                              
                           
                           }
                        
                     
                     }
                  
               
               }

Tracing DLSw Protocol Traffic

To debug the DLSw protocol or trace DLSw protocol traffic, you can specify DLSw–specific options by including the traceoptions statement at the [edit protocols dlsw] hierarchy level:


            
               traceoptions {
               
               file filename <files number> <size size> <world-readable |
                  no-world-readable>;
               
               flag flag;
               
               }

You can specify the following DLSw–specific trace options in the flag statement:

all—Everything
memory—Memory traces
packets—Packet traces
parse—Configuration parse traces
route-socket—Route socket traces

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