CISCO-DLSW-EXT-MIB
The MIB module for management of Cisco specific Data Link Switching protocol enhancements. DLSw is described in RFC 1795 and RFC 2024. DLSw+ Defined Data link switching Plus (DLSw+) is a means of transporting Systems Network Architecture (SNA) and NetBIOS traffic over an IP network. The end systems can attach to the network over Token Ring, Ethernet, Synchronous Data Link Control (SDLC) protocol, or Qualified Logical Link Control (QLLC). DLSw+ switches between diverse media, and locally terminates the data links, keeping acknowledgments, keepalives, and polling off of the WAN. Local termination of data links also eliminates data link control time-outs that can occur during transient network congestion or when rerouting around failed links. Finally, DLSw+ provides a mechanism for dynamically searching a network for SNA or NetBIOS resources and includes caching algorithms that minimize the broadcast traffic required. In this document, DLSw+ routers are referred to as peers, or partners. The connection between two DLSw+ routers is referred to as a peer connection. A DLSw circuit is comprised of the data link control connection between the originating end system and the originating router, the connection between the two routers (typically a TCP connection), and the data link control connection between the target router and the target end system. A single peer connection can carry multiple circuits. The transport connection between DLSw+ routers can vary according to the needs of the network and is not tied to TCP/IP as the DLSw standard is. Cisco supports four different transport protocols between DLSw+ routers: TCP/IP-for transport of SNA and NetBIOS traffic across WANs where local acknowledgment is required to minimize unnecessary traffic and prevent data-link control timeouts and where non-disruptive rerouting around link failures is critical. This transport option is required when DLSw+ is operating in DLSw standards mode. FST/IP-for transport across WANs with an arbitrary topology and with sufficient bandwidth to accommodate SNA and NetBIOS traffic. This solution allows for rerouting around link failures, but recovery may be disruptive depending on the time required to find an alternate path. This option does not support local acknowledgment of frames. Direct-encapsulation for transport across a point-to-point or Frame Relay connection where the benefits of an arbitrary topology are not important and where nondisruptive rerouting around link failures is not required. This option does not support local acknowledgment of frames. DLSw Lite-also known as Logical Link Control, Type2 (LLC2) encapsulation -for transport across a point-to-point connection (currently only Frame Relay is supported) where local acknowledgment and reliable transport are important, but where nondisruptive rerouting around link failures is not required. DLSw Lite uses RFC 1490 encapsulation of LLC2.