IBM BC-203 manual DLSw+ Support for Other SNA Features, BC-212

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Overview of IBM Networking

DLSw+

If you are using NetBIOS applications, note that there are two NetBIOS timers—one at the link level and one at the next higher level. Local acknowledgment for LLC2 is designed to solve link timeouts only. If you are experiencing NetBIOS session timeouts, you have two options:

Experiment with increasing your NetBIOS timers and decreasing your maximum NetBIOS frame size.

Avoid using NetBIOS applications on slow serial lines.

Note By default, the Cisco IOS software translates Token Ring LLC2 to Ethernet 802.3 LLC2. To configure the router to translate Token Ring LLC2 frames into Ethernet 0x80d5 format frames, refer to the section “Enable Token Ring LLC2-to-Ethernet Conversion” in the “Configuring Source-Route Bridging” chapter of the Cisco IOS Bridging and IBM Networking Command Reference, Volume I.

DLSw+ Support for Other SNA Features

DLSw+ can be used as a transport for SNA features such as LAN Network Manager (LNM), DSPU, SNA service point, and SNA Switching Services (SNASw) through a Cisco IOS feature called virtual data-link control (VDLC).

LNM over DLSw+ allows DLSw+ to be used in Token Ring networks that are managed by IBM’s LNM software. Using this feature, LNM can be used to manage Token Ring LANs, control access units, and Token Ring attached devices over a DLSw+ network. All management functions continue to operate as they would in a source-route bridged network or an RSRB network.

DSPU over DLSw+ allows Cisco’s DSPU feature to operate in conjunction with DLSw+ in the same router. DLSw+ can be used either upstream (toward the mainframe) or downstream (away from the mainframe) of DSPU. DSPU concentration consolidates the appearance of multiple physical units (PUs) into a single PU appearance to VTAM, minimizing memory and cycles in central site resources (VTAM, NCP, and routers) and speeding network startup.

SNA service point over DLSw+ allows Cisco’s SNA service point feature to be used in conjunction with DLSw+ in the same router. Using this feature, SNA service point can be configured in remote routers, and DLSw+ can provide the path for the remote service point PU to communicate with NetView. This allows full management visibility of resources from a NetView 390 console, while concurrently offering the value-added features of DLSw+ in an SNA network.

SNASw over DLSw+ allows Cisco’s APPN Branch Extender functionality to be used in conjunction with DLSw+ in the same router. With this feature, DLSw+ can be used to access SNASw in the data center. DLSw+ can also be used as a transport SNASw upstream connectivity, providing nondisruptive recovery from failures. The DLSw+ network can appear as a connection network to the SNASw nodes.

Using DLSw+ as a transport for other Cisco IOS SNA features requires a feature called VDLC. Cisco IOS data-link users (such as LNM, DSPU, SNA service point, and SNASw) write to a virtual data-link control interface. DLSw+ then reads from this interface and sends out the traffic. Similarly, DLSw+ can receive traffic destined for one of these Data Link Users and write it to the virtual data-link control interface, from which the appropriate Data Link User will read it.

In Figure 88, SNASw and DLSw+ use Token Ring and Ethernet, respectively, as “real” data-link controls, and use virtual data-link control to communicate between themselves. When one of the high-layer protocols passes data to the virtual data-link control, the virtual data-link control must pass it to a higher-layer protocol; nothing leaves the virtual data-link control without going through a data-link user.

Cisco IOS Bridging and IBM Networking Configuration Guide

BC-212

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Contents Overview of IBM Networking BC-203Rsrb BC-204Configuration Considerations BC-205DLSw+ BC-206DLSw Version 2 Standard DLSw StandardBC-207 IP Multicast DLSw+ FeaturesEnhanced Peer-on-Demand Routing Feature UDP UnicastLocal Acknowledgment BC-209BC-210 LLC2 Session Without Local AcknowledgmentBC-211 DLSw+ Support for Other SNA Features BC-212Stun Networks Stun and BstunBC-213 Stun Features BC-214BC-215 BC-216 StunBstun Networks Bstun FeaturesLLC2 and Sdlc Parameters BC-217Cisco’s Implementation of LLC2 BC-218Cisco’s Implementation of Sdlc IBM Network Media TranslationBC-219 Virtual Token Ring Concept Sdllc Media Translation FeaturesBC-220 Other Considerations Resolving Differences in LLC2 and Sdlc Frame SizeMaintaining a Dynamic RIF Cache BC-221Qllc Conversion BC-222Cisco’s Implementation of Qllc Conversion BC-223Comparing Qllc Conversion to Sdllc BC-224Other Implementation Considerations BC-225RFC 1490 Routed Format for LLC2 BNN BC-226RFC 1490 Bridged Format for LLC2 BAN BC-227BC-228 NciaNcia Client/Server Model Ncia ServerBC-229 BC-230 Ncia Server Client/Server ModelMigration Support Advantages of the Client/Server ModelExtended Scalability BC-231BC-232 AlpsDspu and SNA Service Point BC-233BC-234 Router Acting as a Dspu ConcentratorBenefits of SNASw SNA Switching ServicesBC-235 IP Infrastructure Support Reduced Configuration RequirementsScalable Appn Networks Network Design SimplicityBranch Extender HPR Capable SNA Routing ServicesBC-237 Enterprise Extender HPR/IP BC-238Dynamic SNA BTU Size Usability FeaturesDynamic CP Name Generation Support Dlur Connect-OutManagement Enhancements Token Ring, Ethernet, and Fddi LAN and IP-Focused Connection TypesTrap MIB Support for Advanced Network Management Awareness Virtual Token RingVirtual Data-Link Control DLC Switching Support for Access to Sdlc and QllcCisco Transaction Connection Native IP Data-Link Control HPR/IPCtrc and Cics BC-243Ctrc and DB2 BC-244Benefits of Ctrc Cmcc Adapter HardwareBC-245 Channel Port Adapter Channel Interface ProcessorBC-246 Parallel Channel Port Adapter Differences between the CIP and CPAEscon Channel Port Adapter BC-247Supported Environments Cmcc Adapter Features for TCP/IP EnvironmentsCommon Link Access to Workstation TCP/IP OffloadCisco Multipath Channel+ IP Host BackupBC-249 Cisco SNA Cmcc Adapter Features for SNA EnvironmentsBC-250 TN3270 Server Cisco Multipath ChannelBC-251 Telnet Server Functions SNA FunctionsBC-252 BC-253 BC-254