Data-Link Switching

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Data-Link Switching (DLSw) is a tunneling protocol designed to tunnel unroutable, non-IP based protocols such as IBM Systems Network Architecture (SNA) and NBF over an IP network.

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DLSw was initially documented in IETF RFC 1434 in 1993. In 1995 it was further documented in the IETF RFC 1795. DLSw version 2 was presented in 1997 in IETF RFC 2166 as an improvement to RFC 1795. Cisco Systems has its own proprietary extensions to DLSw in DLSw+. According to Cisco, DLSw+ is 100% IETF RFC 1795 compliant but includes some proprietary extensions that can be used when both devices are Cisco. [1]

Some organisations are starting to replace DLSw tunneling with the more modern Enterprise Extender [2] (EE) protocol which is a feature of IBM APPN on z/OS systems. Microsoft refers to EE as IPDLC. Enterprise Extender uses UDP traffic at the transport layer rather than the network layer. [3] Cisco deploy Enterprise Extender on their hardware via the IOS feature known as SNAsW (SNA Switch).

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References

  1. "Data-Link Switching (DLSw)". Cisco . Retrieved 2011-06-16.
  2. IBM Corporation. "Enterprise Extender" . Retrieved September 3, 2012.
  3. "Understanding Enterprise Extender, Part 1 - Concepts and Considerations". IBM . Retrieved 2008-09-15.