Network Administrator: four key points of Frame Relay switch Management

WAN connection has many implementation technologies, such as integrated business digital networks and point-to-point protocols. Frame Relay is undoubtedly the most ideal WAN technology for remote connection so far. Frame Relay defines the process of sending data on the public data network, which is suspected of being a high-performance data link layer. It mainly works on the OSI reference model and data link layer, but relies on upper-layer protocols such as TCP for error correction control.

It is said that there is still a fate between the frame relay technology and the integrated business digital network. Because frame relay was originally designed as a protocol running on the integrated business digital network. However, it has become a unique industry standard for the exchange-type data link layer protocol. It uses the Advanced Data Link Control encapsulation protocol to manage virtual circuits between connected devices. Frame Relay uses virtual circuits to establish connections for connection-oriented services.

Frame Relay Technology has now become the most common technology for remote connection in a wide area network. In fact, frame relay technology is still a network connection technology. As long as the network administrator master the key points of its management, he can still easily face it. Specifically, you need to master the following four key points when managing frame relay.

1. Master the management and configuration of local management interfaces

The local management interface is the trust standard between the user station device and the frame relay switch. It is responsible for the connection between devices and maintains the connection status between devices. Cisco's local management interface provides richer management functions. If the maintenance mechanism is supported, the maintenance mechanism is mainly used to verify whether data is being transmitted. If the multi-object transmission mechanism is supported, this mechanism is mainly used to provide local data link identifiers to network servers; for example, global addressing technology is supported. This addressing technology gives the data link connection identifier a global meaning rather than a local meaning in the frame relay network, and is the basis for the implementation of Wan remote connection. Most importantly, Cisco's local management interface also supports the status mechanism. This status Mechanism reports the current status of known data link connection identifiers to the frame relay switch.

Cisco's Frame Relay Device mainly provides three local management interfaces. CISCO, Ansi, and Q933A. Currently, the local management interfaces of many frame relay devices on the market refer to the local management interface models of Cisco frame relay devices. Therefore, in this regard, Cisco's local management interface can be said to be the originator of other frame relay devices.

As a qualified Frame Relay Device administrator, you must be familiar with the features of these three local management interfaces, especially the working principles and related configurations. Understanding the configuration and management of local management interfaces can be said to be the basis for maintaining frame relay.

2. proficient in Frame Relay Multiplexing Technology

In fact, the main problem for devices in the wan to achieve remote connection is stability. Because the Wan is different from the intranet of an enterprise. The enterprise's internal network is more complex, that is, a little device and a little scope. Even if a problem occurs, it can be quickly repaired.

However, the Wan is different. In case of a fault, it is difficult to find the cause of the fault. Even if you find the cause of the fault, it is difficult to fix it in a short time. Just like the network breakdown caused by the last tsunami, the most direct feeling for common users is that MSN cannot be used. Therefore, in the wide area network, it is difficult to solve the problem of stable communication between different network devices.

To solve this problem, frame relay provides a method of multiplexing. Multiplexing is implemented by allocating different data link connection identifiers, sharing physical media, and establishing many Logical Data sessions for each data interruption device. In professional books, this logical session is also called a virtual circuit.

Cisco's frame relay switch provides more flexibility for multiplexing technology, allowing more effective use of existing network bandwidth. Therefore, Frame Relay reduces the connection cost while improving the connection stability of network devices. For example, if there is a wide area network composed of frame relay devices, there will be many links between various frame relay devices. Generally, Wan operators do not have to maintain these links on their own, so they can be handed over to professional companies. Enterprises only need to spend a small amount of money to rent a dedicated road. Of course, if enterprises do not have high requirements for speed, they can spend less to rent a link with others. It seems that the driver only needs to pay the road maintenance fee, instead of building the road on his own and conducting regular maintenance.

The frame relay multiplexing technology seems complicated. In fact, as a network administrator, you only need to master three steps of its implementation. For other work, Cisco's frame relay device will help us solve the problem.

Step 1: The Frame Relay switching device will automatically create a table to print different data link connection identifiers to the outbound port. This table is like a map. When there is a car on the frame relay link, it will not be until the Driver opens.

Step 2: When the frame relay device receives a frame, the switch needs to analyze it. This frame should be suitable for the link. Because the advantage of multiplexing technology is that there are multiple paths at the same time to reach the destination. In this case, the frame relay switching device needs to analyze the table generated in step 1. Based on the shortest path principle or the shortest time principle, it is better to determine which link is used for connection.

Step 3: When the Frame Relay Device selects a reasonable path based on certain judgment principles, the frame will be sent. That is to say, before the first frame is sent, Frame Relay must establish a full path for communication with the target device. Of course, during data transmission, the local management interface will always judge the status of this link. If there is a problem with this link, the frame relay switch will immediately adopt another link to ensure data transmission consistency.

These three steps are the core of multiplexing technology. As a relay network administrator, you need to understand these three basic steps. This is the basis for troubleshooting and Management of Frame Relay networks. Only by mastering these three basic steps can the network administrator solve the problem easily.

Iii. Learn to analyze fault causes through the Frame Relay table

When the frame relay network fails, our network administrator often needs a useful mark, namely, the frame relay exchange table. Through this table, we can find the point where the frame relay network is faulty. We can also identify the cause of the network failure from the information provided in this table. In this way, we can provide data support for fault resolution and shorten the time for fault resolution.

The frame relay exchange table for Cisco frame relay devices usually consists of four entries. Two are used to indicate the inbound port and data link connection identifier, and the other two are the outbound port and data link connection identifier. When a frame passes through each vswitch, the data link connection identifier is re-printed. Generally, the access port of a frame can be changed, but its data link connection identifier cannot be changed.

Therefore, if the network administrator finds that the data link connection identifier of the inbound and outbound ports is inconsistent. For example, if the value is 100 when you enter the vswitch, but the value changes when you exit, you need to consider whether the frame relay device has a problem or whether to cancel the link.

In addition, there may be three connection states in the frame relay table. The administrator can also determine the operation status of the frame relay switch through the connection status.

The first is the active status, indicating that the connection is valid. The Frame Relay switch and the router connected to the frame relay switch can exchange data normally. The second is inactive. It indicates that the local connection to the frame relay switch is valid. However, the remote router to the frame relay switch is abnormal and cannot communicate normally. The third State is the deletion state, which represents two meanings. If there may be no local management interface that can receive information about the frame relay switch, or if there is no service between the user's equipment router and the frame relay switch, no data exchange is performed.

4. Two useful time intervals

There are two important time intervals in frame relay network management. As a network administrator of Frame Relay, you must master its role and related adjustments. These two intervals are often adjusted to improve the performance and stability of the frame relay network to a certain extent.

First, routers exchange reverse ARP information at intervals. The reverse ARP mechanism allows the router to automatically establish frame relay. In fact, the router automatically learns the data exchange path. By default, routers exchange reverse ARP information every 60 seconds.

Second, the router of the user station device sends a maintenance message to the frame relay switch at intervals. The purpose of maintaining information is to verify whether the frame relay switch is working properly. If the design time is too long, the normal data transmission may be affected. If the design time is too short, the network bandwidth consumption will be increased. Therefore, administrators need to evaluate the stability of their networks and the urgency of continuous data exchange to make a proper choice. By default, the interval is 10 S.

The above four highlights are the four main tasks in frame relay network management. Of course, if you really want to become an excellent Frame Relay Network Administrator, you also need to learn about other related technologies, such as global addressing addresses.

1. Frame Relay/ATM service network solution
2. Configure a frame relay switch