A collision domain is, as the name implies, a part of a network where packet collisions can occur. A collision occurs when two devices send a packet at the same time on the shared network segment. The packets collide and both devices must send the packets again, which reduces network efficiency. Collisions are often in a hub environment, because each port on a hub is in the same collision domain. By contrast, each port on a bridge, a switch or a router is in a separate collision domain. Each port of the switch belongs to a single collision domain. In case of switch, the collision domain is limited to each device and in a hub, the collision domain includes all devices connected to the hub.
A broadcast domain is a domain in which a broadcast is forwarded. A broadcast domain contains all devices that can reach each other at the data link layer (OSI layer 2) by using broadcast. All ports on a hub or a switch are by default in the same broadcast domain. All ports on a router are in the different broadcast domains and routers don't forward broadcasts from one broadcast domain to another.
Router is a layer 3 device which works on network layer of OSI model which connects two different networks and it identifies network devices based on their IP addresses.
The Routers are the devices used for connecting local network to the other local network/s. They are generally located at the gateway where two or more than two networks connect.
Switch is a layer 2 device which works on data link layer of OSI model, it communicates by using frames and it identifies network devices on the basis of MAC addresses or physical addresses.
System Switching Board (SSB) and Forwarding Engine Board (FEB) are the two different router models used for the control board functionality.
An aggregate route is the second form of a locally configured route within the JUNOS software.
System Switching Board (SSB) and Forwarding Engine Board (FEB) are the two different router models used for the control board functionality.
An aggregate route is the second form of a locally configured route within the JUNOS software.
Each router model uses a different name for the control board functionality. The possible names include:
Forwarding Engine Board (FEB): The Forwarding Engine Board is found in both the M5 and M10 platforms and integrates the circuit board with the FPC. Each router contains no more than one FEB, which is specific to either the M5 or the M10 chassis.
System Switching Board (SSB):The System Switching Board is found in the M20 platform. Each platform is configured to hold dual SSBs, but only one board is operational at any one time.
System Control Board (SCB): The System Control Board is found in the M40 platform. Each chassis contains no more than one SCB.
Switching and Forwarding Module (SFM): The Switching and Forwarding Module is found in the M40e and M160 platforms. Each M40e router can contain 2 SFMs, with only one operational at a time. The M160 router contains four SFMs working in parallel.
Memory Mezzanine Board (MMB): The Memory Mezzanine Board is found in the T320 and T640 platforms and is located on the FPC itself.
Each Routing and Control Board (RCB) consists of the following internal components:
CPU-Runs Junos OS to maintain the routing tables and routing protocols and handles these exception packets and performs the appropriate action.
EEPROM- Stores the serial number of the Routing Engine.
DRAM-Provides storage for the routing and forwarding tables and for other Routing Engine processes.
