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Browse Prior Art Database

High Speed Network Adapter with Isochronous Traffic Support

IP.com Disclosure Number: IPCOM000104071D
Original Publication Date: 1993-Mar-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 4 page(s) / 122K

Publishing Venue

IBM

Related People

Willebeek-LeMair, M: AUTHOR [+4]

Abstract

This invention describes the architecture of an FDDI-II net- work adapter which supports isochronous data transport in addition to the standard packet transport. The design is based on the bus based packet transport adapter for FDDI-I (Fig. 1) with certain modifications and additions to support the hybrid traffic mode of FDDI-II. The adapter is designed to support multiple physical attachments, which are all con- nected to the adapter bus. The architecture can support anywhere from a single host-to-FDDI-II connection up to mul- tiple FDDI-II connections as required by a bridge or a router.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

High Speed Network Adapter with Isochronous Traffic Support

      This invention describes the architecture of an FDDI-II net-
work  adapter  which  supports isochronous data transport in addition
to the standard packet transport.   The  design  is based  on  the
bus based packet transport adapter for FDDI-I (Fig. 1) with certain
modifications and additions to support the hybrid traffic mode of
FDDI-II.  The adapter is designed to support multiple physical
attachments, which are all con- nected to the adapter bus.   The
architecture  can  support anywhere from a single host-to-FDDI-II
connection up to mul- tiple  FDDI-II  connections  as  required  by
a bridge or a router.

      A block diagram of the adapter is shown in Fig. 1.   Attach-
ment  Interface Modules (AIMs) are used to connect different physical
attachments.  The AIM is logically divided  into  a Receiving  AIM
(RCV_AIM) Transmitting AIM (XMT_AIM) the por- tion of the AIM whose
function it is to receive and transmit data onto the network or to a
host, respectively.

      A block diagram of the RCV_AIM is shown in  Fig.  1.    Each
RCV_AIM  has  a  dedicated set of Compressed Cycle Registers (CCRs);
one for each possible destination within the adapter (including hosts
and other networks).   The CCR is  used  to store all the octets of
data being transferred, within a cy- cle, between two AIMs.  A Cycle
Routing Map (CRM), specifies the CCR (corresponding to the
destination AIM) to which each arriving octet is written.  The CRM is
based on the Steering Map  and  the  adapter addressing scheme.  If a
Transmission Channel is open to this station then it will  have  a
valid destination address in the CRM corresponding to the destina-
tion AIM in the adapter.

      The RCV_AIM operation is illustrated in Fig. 2.  In this ex-
ample, the adapter includes five AIMs, four of which are at- tached
to  independent FDDI-II networks and one of which is attached to a
host (AIM_2).   Furthermore, each  cycle  con- sists of five WBCs of
four octets each.  The connections es- tablished   between   AIM_3
and...