Highlights of SQL Server 2005 Communication Protocol Enhancements

Welcome to the new SQL Server Protocols team blog site.  SQL Server 2005 (aka Yukon) will be released with an impressive list of new features and capabilities and I'd like to highlight some of the enhancements to the connectivity/protocols layer of SQL Server 2005.

New Features

  • Improved Error Messages
    We no longer report connectivity errors as a GNE (General Network Error).  Whenever possible, the error message is propagated from the server to the client so that the source of the problem may be more easily identified
  • Self-signed SSL Certificates
    The server is now capable of generating a self-signed SSL certificate if a certificate hasn't been provisioned on the machine.  This means that the server will always be capable of performing encryption (although for security reasons, a provisioned certificate is still recommended).  A consequence of this is that the login packet will be encrypted whenever possible
    SQL Server now provides support for native XML web services over HTTP.
  • Dedicated Admin Connection (DAC)
    The DAC is a specialized connection intended for diagnostics and troubleshooting.  The server actually reserves a separate set of resources for the DAC and isolates it from normal connections so that there is a good chance that a DAC connection will be available even though normal connections may not.
  • SQL Browser
    The responsibility of responding to SSRP requests for providing protocol information to clients is now handled by a separate service called SQL Browser.  The removal of this functionality from the server process reduces the attack surface area.
  • TDS Endpoints
    Endpoints are objects that represent a communication point between the server and a client.  Using TDS endpoints, a connection privileges may be configured at a finer granularity
  • SQL Network Interface (SNI)
    SNI is a replacement for Netlibs and provides a common communication transport layer for the client and server.  One of the benefits of SNI is that it provides a built-in tracing capability which greatly aids in debugging problems.
  • Multi-homed TCP/IP support
    The server may be configured to listen on individual IP addresses and ports
  • NUMA
    NUMA nodes can now be affinitized to TCP/IP ports in addition to VIA



  • Reduced Protocol List
    The only protocols to consider now are TCP/IP, Named Pipes, and Shared Memory.  Banyan Vines, Multiprotocol, AppleTalk, and IPX/SPC have all been deprecated
  • Shared Memory
    The shared memory implementation has changed from SQL Server 2000 for security and performance reasons.
  • VIA
    The VIA protocol supports the QLogic driver by default but may be configured to use any other driver
  • Connection String
    Connection strings can use an explicit protocol prefix, e.g., tcp:, to force a particular protocol without failing over to other protocols

I've only provided a brief summary but some of the items will be explained in greater detail in future posts.  Please let me know if any of them are of particular interest to you and I'll try to provide more info.

Il-Sung Lee
Program Manager, SQL Server Protocols

Disclaimer: This posting is provided "AS IS" with no warranties, and confers no rights

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