Browse Prior Art Database

Reduction of NetBIOS Broadcast Storms Caused by Group Name Discovery

IP.com Disclosure Number: IPCOM000116007D
Original Publication Date: 1995-Jul-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 87K

Publishing Venue

IBM

Related People

Anand, VK: AUTHOR [+2]

Abstract

NetBIOS* implemented using Transmission Control Protocol/Intent Protocol (TCP/IP) as the transport mechanism presents some additional difficulties not found in standard NetBIOS implementations using the IEEE 802.2 protocol as the transport mechanism. NetBIOS over TCP/IP is fully described in two internet Request For Comments (RFCs) documents numbered 1001 and 1002. This disclosure addresses the problem of sending a NetBIOS datagram to a NetBIOS Group Name. (A NetBIOS group name is a name that can be shared by many workstations, which differs from a NetBIOS unique name which can be owned by only one workstation.)

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Reduction of NetBIOS Broadcast Storms Caused by Group Name Discovery

      NetBIOS* implemented using Transmission Control Protocol/Intent
Protocol (TCP/IP) as the transport mechanism presents some additional
difficulties not found in standard NetBIOS implementations using the
IEEE 802.2 protocol as the transport mechanism.  NetBIOS over TCP/IP
is fully described in two internet Request For Comments (RFCs)
documents numbered 1001 and 1002.  This disclosure addresses the
problem of sending a NetBIOS datagram to a NetBIOS Group Name.  (A
NetBIOS group name is a name that can be shared by many workstations,
which differs from a NetBIOS unique name which can be owned by only
one workstation.)

      First, review how a datagram is sent to a group name in
standard NetBIOS using 802.2 as the transport protocol.  A NetBIOS
application issues a NetBIOS Control Block (NCB) with command code
set to send datagram to the NetBIOS component.  The application
specifies the destination NetBIOS name as a group name.  The NetBIOS
component builds a send datagram NetBIOS packet and specifies the
destination network address as the NetBIOS Functional Address (IEEE
802.2 supports functional addresses).  The packet is sent by the
802.2 transport component.  The packet will be received by all
NetBIOS workstations which have added the NetBIOS functional address.

      The method used by standard NetBIOS will not work when TCP/IP
is the underlying transport.  The reason is that TCP/IP does not
support functional addresses.  The RFCs 1001/1002 state that when
sending a datagram, the NetBIOS component must first do name
discovery on the destination name.  This results in a name query
packet being broadcast to the network.  When name recognized response
packets are received, the response packet is checked to see if the
responding workstation has the name registered as a group name.  If
so, the datagram is being sent to a group name and must broadcast the
datagram to the network.  There is one tremendous problem with this
method for sending a datagram to a group name.  The problem is that a
network broadcast storm can be created by sending a...