a. I.A.Ring Single-ring Backup
I.A. Ring/I.A. Chain is the latest generation of network backup protocol of ISON Company. In the IT network system in the past, little concern is given to this aspect. However, backup technology plays an extremely important rolein application to industrial environment.
Under the architecture of Ether network, both Ringed and Meshed network architectures are inapplicable due to formation of loop of the network, and leading to occurrence of Broadcast Storm. As a result, STP(Spanning Tree Protocol) appears inIT application, which can block redundant circuits, prevent the network from generating broadcast storm, and achieve the effect of circuit backup.
Under STP, when changes take place in network topology, such as increasing the number of circuits or the network disconnecting, it will take basically 30 seconds or above to adjust the whole network system to resume working. During this period of time, the whole network stay in the state of stopping working, and any data exchange between the packets, data or any nodes will not proceed. However, with development of IT industry, for the purpose of improving overly long break-down time, the STP protocol has evolved into RSTP(Rapid Spanning Tree Protocol),which just requires less than 5 seconds to resume the break-down time of the network. Such evolution can sufficiently satisfy the demand of general application. Unfortunately, for applications to specific industrial environments like wafer factory, nuclear power plant, etc., network interruption for one second may result in prominent loss, let alone for five seconds. At this point, for ISON used in the industrial Ether network i-switch, the specified Protocol of I.A.Ring can be formulated in order to decrease time of network interruption with expectations on lessening data loss and damage of system breakdown to the least degree.
Protocol of ISONI.A.Ring is a function design exclusively for circuit backup. The Ring network topology is one that can save the most circuit materials and achieve the optimal backup ability in a variety of network topologies (See Fig. 1).
(Figure 1) Ring Topology can save expense of the line materials
The basic functions and operation method are similar to STP/RSTP by blocking certain backup line segment as it is done in general. Once change of network topology occurs, such as line interruption or the network i-switch break-down, the blocked circuits can be opened to resume operation of network, as Fig. 2 shows. The biggest advantage lies in thatthe network can resume normal operation with extremely short time about 20ms, even if the single ring network topology has achieved 250pcs' architecture of switch (approaching the node number of Class C network segment), so that the user can hardly be aware of any change occurring in the network. Even so, through the functions of software including Alarm, E-Mail, SNMP Trap, etc. or those of hardware like Relay and LED light, the i-switch will actively advise the administrator that specific network problem has occurred. In such case, thanks to the back-up circuit mechanism, the system administrator can proceed repair or maintenance at site with ease. In addition, when the administrator intends to adjust network topology, such as adding or reducing the network equipment or i-switches, he/she can pushes or plugs the circuits directly without shutting down the whole system, which can help considerably in respect with maintaining and upgrading the system.
(Figure 2) When change occurs in the network topology, the blocked terminal will open
b. Ring Coupling Redundant path between Rings
The Ring Backup Network owns backup circuits and a rapid system recovery speed, although the Single Ring Network may encounter issues involving difficulty in progressively extending the network to a wider area or insufficient connections, when applied to a more disperse environment or larger and more complicated network system. The Ring Backup can help here, since this function is to connect between Ring Networks or the local end system with the backbone network, as Fig. 3 presents.
(Figure 3) Establish the backup circuits between two Ring Networks, and block one circuit
Ring Coupling Configuration
It is risky to connect merely one circuit between two Ring Networks; therefore,circuit backup is set up through connecting two circuits. However, in connecting two circuits, network loop will occur. In such case, as I.A.Ring, Ring Coupling function will block one segment of the circuit, and will open only when the switch or the circuit breaks down, as Fig. 4 shows.
(Figure 4) When the circuit breaks down, the blocked terminal will open.
In Fig. 4, four switches are exerted to connect the backup circuits for two Ring Networks, which can achieve the circuits' backup effect. On the other hand, when one of the four switches connecting two Ring Networks breaks down, or when the network interrupts, communication between the two Ring Networks remains normal, since under the basic application concept, Ring Coupling has varied connecting methods--A Dual Ring, or B. Dual-homing, as Fig. 5 presents.
(Figure 5) Establish backup circuits for two Ring Networks and block one of the circuits
In Dual-Homing mode, two connecting points are set on a switch-- one to connect the primary line, and the other to link the backup line. Dual Ring Mode is a more economic choice, since only one switch is employed to connect the two Ring Networks. However, in using the two modes, User has to consider occurrence of single-point failure in using only one switch; for example, the switch may be broken down or destroyed by irresistible external force. Then, the system constructor can conduct system planning and installation based on the environment that is actually applied and the customer's demand. In addition, according to different backup levels, appropriate backup function mode must be chosen for the system to proceedoptimization, unrestricted extension, or system decentralization and deployment. For this function, flexibility is the biggest advantage.
c. I.A. Chain Backup Function
I.A. Chain (Daisy Chain) is transformed through the function of Ring coupling. After combining the Ring with Ring Coupling, a circuit is taken from the Ring, achieving the optimal combination of backup ability and saving circuit expense. The advantage is not only saving the expense of circuits, but also extending outwards from the core end on the basis of design consideration, which achieves ability of enlarging the network topology without interrupting the existing application, together with considerable convenience and high application flexibility. However, the disadvantages involve with bandwidth's utilization of settings restricted to the circuits' setting, so data always flow towards the same direction, which is inapplicable to environment with high bandwidth loadings.
I.A. Chain (NLB, Network Load Balancing Chain), this new function was extended from the Daisy Chain concept with new features to overcome Daisy Chain’s bandwidth congestion problems. User can have all of Daisy Chain's advantages and convenience. For example, under the high speed network topology at high speed and high density, the bandwidth can gain bypass decentralized to different nodes in the network, have the whole network system own the setting with the most flexible freedom, and gain the bandwidth management function.
Regardless of Daisy chain type or NLB Load balancing type, I.A.Chain can mix with and connect to the switch at the core end without shutting down the core switch nor changing the setting, demonstrating the flexibility and convenience in practical use.
The method to set I.A.Ring/I.A.Chain is simple and easy. Through three setting logic groups, User can accomplish backup setting on the switch. The setting method is as follows: 1. After deciding the role mode of the switch, select two connecting ports for the switch; 2. Click "Save" to save the setting; 3. According to the system architecture diagram, set the role played by each switch, and finish the setting. Additionally, after completing all settings, keep in mind that you go to the Running Configuration Setting Page, and save the changed setting files as the Executable for booting next time.
Note: Upon using I.A.Ring/Chain function, please close the RSTP/STP, Loop protection function.