Multiplex communications – Communication techniques for information carried in plural... – Adaptive
Reexamination Certificate
1998-04-14
2001-06-26
Olms, Douglas (Department: 2732)
Multiplex communications
Communication techniques for information carried in plural...
Adaptive
C370S242000, C370S401000, C370S470000
Reexamination Certificate
active
06252888
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to data communications networks and, more specifically, the present invention relates to virtual local area networks.
2. Background Information
A Local Area Network (LAN) has generally been defined as a network of computers or workstations located within a single broadcast domain. Computers that are connected to the LAN can become connected for the interchange of data. Once a message transmitted to the LAN, the message is broadcast to and received by every other user connected to the LAN.
Virtual LANs (VLANs) are used to segment networks into logically defined virtual workgroups. By logically separating the segments, messages are generally broadcast only to the workstations in the logical segment. As a result, the overall traffic is reduced since traffic remains within the segment. In addition, an added level of security is realized with VLANs since workstation users no longer receive broadcasts addressed to other segments.
There are varieties of known methods to identify and route data between workstations in a VLAN. One method is explicit tagging, which involves a VLAN tag being added to an ordinary data packet or frame. The VLAN tag indicates, among other things, the VLAN to which the data frame belongs. Another method of identifying and routing data between workstations in a VLAN is implicit tagging. Implicit tagging methods include associating a particular set of ports to a particular VLAN or associating particular communications protocol to a particular VLAN.
In some instances, some of the workstations that are connected to the VLAN may be “VLAN aware.” These workstations recognize the VLAN tags that are added to the ordinary data frames. In other instances, the workstations that are connected to the VLAN are “non-VLAN aware.” These workstations do not recognize the VLAN tags that are added to the data frames.
What is desired is a method and an apparatus providing data communications in networks such as VLANs. Such a method and apparatus should have the ability to transfer tagged and untagged data frames among VLAN aware and non-VLAN unaware workstations. Such a method and apparatus should convert the data frames as appropriate to enable compatibility with both the VLAN aware and non-VLAN unaware workstations. In addition, error correction codes in the frames should be maintained accordingly.
SUMMARY OF THE INVENTION
A method of communicating between a first device and a second device in a data communications network is disclosed. In one embodiment, a frame is received with a first error detection code from the first device at an inbound port of the network, the first error detection code corresponding to the frame as sent to the inbound port. The frame is converted to a first format if the frame was not sent to the inbound port in the first format. The frame is then forwarded in the first format with the first error detection code from the inbound port to an outbound port of the network. The frame is then converted to a second format if the second device recognizes the second format. Afterwards, the frame is sent from the outbound port to the second device. A second error detection code is generated corresponding to the frame as sent from the outbound port to the second device. The frame as sent to the inbound port and forwarded through the network is verified against the first error detection code. If an error is detected in the verification step, then the second error detection code is corrupted. The second error detection code is then forwarded from the outbound port to the second device. Additional features and benefits of the present invention will become apparent from the detailed description, figures and claims set forth below.
REFERENCES:
patent: 5872781 (1999-02-01), Bennett et al.
patent: 5935268 (1999-08-01), Weaver
patent: 5987034 (1999-11-01), Simon et al.
patent: 6038227 (2000-03-01), Farris et al.
patent: 6049528 (2000-04-01), Hendel et al.
patent: 6094439 (2000-07-01), Krishna et al.
“Release Notes for the BayStack Model 350T 10/100 Autosense Switch” Part No. 896-00162-A, Bay Networks, Mar. 1997.
“Switch Node Product Description” Part. No. 11347 Rev. A, Bay Networks,May 1997.
“Ethernet Tutorial” at http://www.six.es/tutorial.htm, Manual Ethernet Page, Mar. 8, 1998.
“Virtual LAN Communications” at http://cio.cisco.com/warp/public/614/13.html, Cisco Systems Inc., Jan. 28, 1998.
“VLAN Interoperability” at http//cto.cisco.com/warp/public/537/6.html, Cisco Systems Inc, 1996.
“Virtual Lan Communications”, at http://cio.cisco.com/warp/public/614/13/html, Cisco Systems Inc., 1996.
“3COM Transcend VLANs: Leveraging Virtual LAN Technology to Make Networking Easier”, 3Com Strategic Directions, 3Com Corp., 1996.
“The Virtual LAN Technology Report” at http://www.3com.com
sc/200374.html, 3COM Corp, Jan. 28, 1998.
“Fast IP: Enhanced Performance and Control in Switched Networks”, 3Com Technical Papers, 3Com Corp., 1997.
“Virtual Local Area Nwtworks” at http://www.cis.ohio.state.edu/-jain/cis788-97/virtual_lans/index.htm, Cisco Systems Inc., modified Aug. 14, 1997.
Network 21 Cutover Workgroup: VLAN Information and Implementation (Draft ver 1.03, at http:/
et21policy.ucdavis.edu
ewvlan.html;, Jan. 28, 1998.
Fite, Jr. David B.
Ilyadis Nicholas
Salett Ronald M.
Hom Shick
Nortel Networks Corporation
Olms Douglas
Sokoloff Blakely
Taylor & Zafman LLP
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