Dell PowerConnect J-8216 Software Guide for JUNOS version 10.3 - Page 95

Chapter 1: Software Overview • Maintains the routing tables used by the switch and controls the routing protocols that run on the switch. • Provides control and monitoring functions for the switch, including controlling power and monitoring system status. Junos OS Processes Junos OS running on the Routing Engine and Packet Forwarding Engine consists of multiple processes that are responsible for individual functions. The separation of functions provides operational stability, because each process accesses its own protected memory space. In addition, because each process is a separate software package, you can selectively upgrade all or part of Junos OS, for added flexibility. Table 20 on page 23 describes the primary Junos OS processes. Table 20: Junos OS Processes Process Name Description Chassis process chassisd Detects hardware on the system that is used to configure network interfaces. Monitors the physical status of hardware components and field-replaceable units (FRUs), detecting when environment sensors such as temperature sensors are triggered. Relays signals and interrupts-for example, when devices are taken offline, so that the system can close sessions and shut down gracefully. Ethernet switching process eswd Handles Layer 2 switching functionality such as MAC address learning, Spanning Tree protocol and access port security. The process is also responsible for managing Ethernet switching interfaces, VLANs, and VLAN interfaces. Manages Ethernet switching interfaces, VLANs, and VLAN interfaces. Forwarding process pfem Defines how routing protocols operate on the switch. The overall performance of the switch is largely determined by the effectiveness of the forwarding process. Interface dcd process Configures and monitors network interfaces by defining physical characteristics such as link encapsulation, hold times, and keepalive timers. Management process mgd Provides communication between the other processes and an interface to the configuration database. Populates the configuration database with configuration information and retrieves the information when queried by other processes to ensure that the system operates as configured. Interacts with the other processes when commands are issued through one of the user interfaces on the switch. If a process terminates or fails to start when called, the management process attempts to restart it a limited number of times to prevent thrashing and logs any failure information for further investigation. 23