Network server having dynamic load balancing of messages in both inbound and outbound directions

• US 6,243,360 B1
• Filed: 09/21/1998
• Issued: 06/05/2001
• Est. Priority Date: 09/18/1996
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Basilico, Albert Richard
• Primary Examiner(s): HSU, ALPUS
• Application Number:
  US09/157,740
• Time in Patent Office: 988 Days
• Field of Search: 370/230, 370/231, 370/235, 370/389, 370/392, 370/419, 370/420, 370/421, 370/422, 370/423, 370/463, 709/203, 709/230, 709/232, 709/234, 709/238, 709/240, 709/249, 709/250
• US Class Current: 370/231
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 45/742 Route cache; Operation thereof
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/10015 Access to distributed or replicated servers, e.g. using brokers
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/1023 based on a hash applied to IP addresses or costs
• CPC Class Codes: H04L 67/62 Establishing a time schedule for servicing the requests
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A communications network including a server having multiple entry ports and a plurality of workstations dynamically balances inbound and outbound to/from the server thereby reducing network latency and increasing network throughput. Workstations send data packets including network destination addresses to a network switch. A header is prepended to the data packet, the header identifying a switch output or destination port for transmitting the data packet to the network destination address. The network switch transfers the data packet from the switch input port to the switch destination output port whereby whenever the switch receives a data packet with the server address, the data packet is routed to any available output port of the switch that is connected to a Network Interface Card in the server. The switch includes circuitry for removing the routing header prior to the data packet exiting the switch. The server includes circuitry for returning to the workstation the address of the first entry port into the server or other network device that has more than one Network Interface Card installed therein.

Claims

1. A communications network including:

a server having a plurality of entry ports;

a plurality of workstations;

a network switch coupling the server to the plurality of workstations;

a Network Interface Card in at least one of the workstations for sending data frames including network destination addresses to the network switch;

a destination address locator, positioned in said network switch, using a network destination address in said frame to generate and record an indicia in said frame representative of a port whereat the server is coupled to said network switch;

a switch controller correlating the indicia in said frame with entries in a switch route table and routing the frame to an output port associated with an entry in said switch route table that matches the indicia or to another port in a group of ports associated with the output port if said output port is busy.

2. The apparatus of claim 1 wherein the switch controller sequentially monitors the output port and group of ports to determine a non-busy port through which the frame is routed.

3. In a communications network including a server having multiple entry ports coupled to a plurality of workstations through a network switch, a method of dynamically balancing in-bound and out-bound messages to/from the multiple entry port server comprising the steps of:

a) transmitting data packets including network destination addresses to the network switch;

a1) associating multiple ports of the server with multiple output ports of said switch;

b) appending a header to the data frame, the header identifying one of the multiple output ports of said switch as destination port for transmitting one of the data packets;

c) examining a port entry bit associated with one of the multiple output ports to determine if said output port is busy;

d) if the switch output port is busy, sequentially monitoring the multiple output ports to detect a non-busy one; and

e) routing the frame through the non-busy one to the server.

4. The method of claim 3 further including the steps if the switch output port is not busy routing the data frame through said not-busy output port;

and

removing the routing header prior to the data frame exiting the switch.

5. In a communications network including a server having multiple ports with each one coupled to a port of a switch and said switch coupled through other ones of its ports to a plurality of workstations, a method for dynamically balancing inbound and outbound messages to/from the server including the steps of:

a) receiving in said switch a message including a destination address;

b) determining if the destination address is that of the server;

b1) determining a group of switch output ports coupled to the server;

c) if the destination address is the address of the server, sequentially monitoring ports in the switch output group of ports to detect a non-busy one; and

d) routing the frame through the selected non-busy one of the group of ports.

6. A network switch comprising:

at least one input port that receives frame;

a plurality of output ports some of which are grouped to provide service to one device;

a destination address locator responsive to addresses in each of the received frames to generate and record header indicia in said each one of the received frames wherein the indicia relates to an output port to which the frame is to be routed;

a switch route table including header indicia entries and associated output port number entries; and

a switch controller correlating header indicia in each frame with entries in the switch route table and routing the frame to an output port corresponding to matched entries or to a non-busy port in ports grouped with output port if the output port is busy.

7. The network switch of claim 6 wherein the device includes a server.

8. The network switch of claim 7 further including a content addressable memory and a random access memory for associating a network switch port with a network interface Card in the server.

9. The network switch of claim 6 further including:

a) means for indicating that a destination port does not have a unique output routing; and

b) means for indicating that the destination port is currently busy.

10. The network switch of claim 6 further including a switch fabric coupled to the at least one input port and the plurality of output ports and a control signal bus linking input and output ports.

11. The network switch of claim 6 wherein the destination address locator includes:

a Contents Address Memory (CAM);

a Random Address Memory (RAM), operatively coupled to the CAM; and

a CAM/RAM controller that conducts control search of said CAM and RAM to identify the header indicia.

12. The network switch of claim 11 wherein the CAM/RAM controller includes a processor or Application Specific Integrated Circuit (ASIC).