Browse Prior Art Database

Mechanism to Automatically Align Packets in Switch Adapters

IP.com Disclosure Number: IPCOM000115302D
Original Publication Date: 1995-Apr-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 66K

Publishing Venue

IBM

Related People

Galand, C: AUTHOR [+4]

Abstract

In a fast packet switched network, data packets are received from a terminal equipment in a receive port adapter which is connected to a switch.

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

Mechanism to Automatically Align Packets in Switch Adapters

      In a fast packet switched network, data packets are received
from a terminal equipment in a receive port adapter which is
connected to a switch.

      In the port adapter, the data packets are processed according
to the protocol used in the terminal equipment, and then routed
through the network.  The routing operation results in appending the
packet with a network routing header NH which is used at each
switching node along the route of the packet to switch the packet to
the adequate output adapter.  The NH may be of fixed or variable
length.  It is of fixed length when it carries a label which has been
defined at the connection set-up (label swap), and it is of variable
length when it carries the entire sequence of successive labels to be
used at each switching node (source routing).

      It is clear that the network header NH is required in all trunk
adapters in the network, but must be removed in the last port of the
network, since the connected equipment expects to receive the
original payload.  Under the assumption that the adapters require
full 4-byte alignment, this requirement translates into a different
alignment of the data representing the packet in port and trunk
adapters.

      It may happen however in a multicast scenario, that a packet
arrives at a switch receive adapter A and must be transmitted to two
different transmit adapters: one trunk adapter B, and one port
adapter C.  Th...