3Com 86-0621-000, C36460T DLSw CONNectUsage Parameter Default Change, Leaf Node Sessions Support

48

Boundary Routing and When configuring NetView Service Point in a Boundary Routing environment, NetView Service Point note that the SSCP-PU session actually flows over LLC2 rather than DLSw, even

though the -SNA PortDef parameter is defined as DLSw. As a result, the session does not show up as a DLSw circuit.

Configuring BSC When connecting a NETBuilder bridge/router to an Network Control Program and NCPs (NCP) for a BSC configuration, be careful when disabling the 3780/2780 EP lines.

If you try to pull the cable out, the NCP may go into a state that will require the NCP to be rebooted. Check with your IBM service representative for additional details.

DLSw Circuit Balancing Circuit balancing does not work properly if WAN links are set to different speeds. For circuit balancing to work properly, you must have WAN links of the same speed. If the WAN links are different speeds, for example, T1 and 64 K, the bridge/router with circuit balancing learns the route from the T1 link before learning the route from the 64 K link. All circuits are directed to the DLSw tunnel on the T1 link instead of being distributed on both 64 K and T1 DLSw tunnels. Only after alternate routes are in the circuit-balancing router cache will subsequent session establishment be balanced.

DLSw and

CONNectUsage

Parameter

Default Change

The default value of the -SYS CONNectUsage parameter is High for NETBuilder bridge/routers with a DPE module. The default value of CONNectUsage for all other platforms is Low. This difference simplifies DLSw configurations.

When the DPE module is used in a non-DLSw configuration, a small amount of memory is allocated (226 K of approximately 12 MB). Non-DLSw configurations in very large networks running OSPF and BGP may require that the CONNectUsage parameter be changed to Low to recapture this 226 K of memory. For all other configurations, this additional small memory allocation should have no effect.

DLSw Prioritization

DLSw and IBM Boundary

Routing in Large

Networks

The FLush -SYS STATistics command does not flush DLSw priority statistics. You must use the FLush -DLSw PRioritySTATistics command.

The following considerations are related to DLSw in large networks.

Leaf Node Sessions Support

When a leaf node has more than 50 end stations, use the following tuning parameters:

SETDefault !<port> -LLC2 TransmitWindow = 1

SETDefault !<port> -LLC2 RetryCount = 20

SETDefault !<port> -LLC2 TImerReply = 10000

Use these parameters for the leaf node and central node WAN ports.

Number of DLSw Circuits

The -SYS CONNectionUsage parameter controls the maximum number of DLSw circuits. The default value of the CONNectionUsage parameter is High for NETBuilder bridge/router with a DPE module and for the boundary router peripheral node, but the default value is low for all other NETBuilder bridge/router platforms. Change this value using:

SETDefault -SYS CONNectionUsage = Low Medium High