Server Message Block: Difference between revisions

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=== SMB 2.0 ===

Microsoft introduced a new version of the protocol (SMB 2.0 or SMB2) in 2006 with [[Windows Vista]] and [[Windows Server 2008]].<ref name="smb2">{{cite web | url=http://blogs.msdn.com/chkdsk/archive/2006/03/10/548787.aspx | title=What's new in SMB in Windows Vista | date=March 10, 2006 | access-date=May 1, 2006 | author=Navjot Virk and Prashanth Prahalad | work=Chk Your Dsks | publisher=[[Microsoft]] | url-status=dead | archive-url=https://web.archive.org/web/20060505005515/http://blogs.msdn.com/chkdsk/archive/2006/03/10/548787.aspx | archive-date=May 5, 2006 | df=mdy-all }}</ref> Although the protocol is proprietary, its specification has been published to allow other systems to interoperate with Microsoft operating systems that use the new protocol.<ref>{{cite techreporttech report |url=https://docs.microsoft.com/openspecs/windows_protocols/ms-smb2 |title=Server Message Block (SMB) Protocol Versions 2 and 3 |department=Windows Protocols |work=Open Specifications |series=[[Microsoft Docs]] |institution=[[Microsoft]] |number=MS-SMB2 |access-date=2020-11-29}}</ref>

SMB2 reduces the 'chattiness' of the SMB 1.0 protocol by reducing the number of commands and subcommands from over a hundred to just nineteen.<ref name="barreto"/> It has mechanisms for [[Pipeline (computing)|pipelining]], that is, sending additional requests before the response to a previous request arrives, thereby improving performance over high-[[Latency (engineering)|latency]] links. It adds the ability to compound multiple actions into a single request, which significantly reduces the number of [[round-trip delay time|round-trips]] the client needs to make to the server, improving performance as a result.<ref name="barreto"/> SMB1 also has a compounding mechanism—known as AndX—to compound multiple actions, but Microsoft clients rarely use AndX.{{Citation needed|date=November 2010}} It also introduces the notion of "durable file handles": these allow a connection to an SMB server to survive brief network outages, as are typical in a wireless network, without having to incur the overhead of re-negotiating a new session.