Hubs & Switches Ethernet Basics -10

There is only so much available bandwidth, in some instances it can be dynamic An overabundance of data on the network, not only affects the infrastructure equipment tasked with its distribution, but also the end devices or nodes meant to receive it. Once a node has been overwhelmed, it needs to recuperate or recover and so called “time outs” can occur. Hubs & Switches

To understand the differences between Hubs, Switches, and Managed switches, the 3 types of traffic must be understood There are 3 types of ‘traffic’ 1.Unicast 2.Multicast 3.Broadcast

Traffic Types - Unicast Unicast = 1 to 1 communication. Traffic generated by one device meant specifically for another.

Multicast = 1 to many nodes communication. Traffic generated by one device meant for multiple nodes but not necessarily all nodes Traffic Types - Multicast

Broadcast = 1 to all nodes communication. Traffic generated by one device and sent to all other devices. Traffic Types - Broadcast

The type of traffic directly effects the amount of traffic on a Network or "Networking" device The amount of traffic directly effects the bandwidth utilization of that device. The bandwidth utilized on the device effects the device’s ability to transmit and receive data in an efficient manner. Network performance will degrade if too much bandwidth is used because of too much of the wrong kind of traffic Traffic Types – Unicast, Multicast and Broadcast

Devices which regenerate incoming signals (frames) and distribute them to all other ports. (Broadcast) Considered to be “dumb” devices (indiscriminately send data everyone with no means to filter it) Do not support 10/100 auto-sensing (either 10BASE OR 100BASE) Subject to rules of Propagation Equivalent and Variability Value (Calculations necessary for a “collision domain”) Hubs

To PLC 1 From I/O 1 PLC1 To PLC 1 From I/O 1 To PLC 1 From I/O 1 To PLC 1 From I/O 1 Operating mode of a Hub Data Storage server

I/O 1 PLC 1 To I/O 1 From PLC 1 To I/O 1 From PLC 1 To I/O 1 From PLC 1 To I/O 1 From PLC 1 Operating mode of a Hub Data Storage server

Operating method of a Hub

A Device which delivers a received Unicast data packet only to that port on which the destination station is connected. ALL switches on the network instantly recognize newly attached devices, read MAC address and records that into its address table RJ45 ports are typically 10/100 auto-negotiation/crossing Multiple versions for variety of RJ45/Fiber port configurations It is a good practice to keep extra ports for expansion, laptop access and networking to rest of network Unmanaged Switches

Managed switches can operate on a network without any set up programming as do Unmanaged switches Managed switches can be given their own IP address, permitting custom configuration of ports and overall control of switch SNMP software as well as other methods allow for the monitoring and configuration of (alarming, bandwidth utilization, security, etc.) Managed Switches

To PLC B From PC 12 PLC B PLC A To PLC B From PC 12 On a switch, each port is a Collision Domain Can 10/100mbps Half or Full Duplex Unicast traffic is sent only to the port it is destined to go Operating mode of a Switch

How does a switch direct Unicast traffic efficiently? PLC A PLC C PLC B RC 13 RC 12 RC 11 P1 P4 P3 P2 P5 PC 1 Address table Port 1 Port 2Port 4 Port 5 PC 1RC 11 RC 12 RC 13 PLC BPLC A Port 3 PLC C Operating mode of a Switch

Address table PC 1 PLC C To PLC C From PC 1 Port 1 Port 2Port 4 Port 5 To PLC C From PC 1 PLC A PLC B RC 13 RC 12 RC 11 PC 1RC 11 RC 12 RC 13 PLC B P1 P4 P3 P2 P5 PLC A Port 3 PLC C Port 3 PLC C Operating mode of a switch

Address table Port 1 Port 4 Port 5 PLC 1 Port 2 RC 11 RC 12 RC 13 PLC C P3 PC 1 RC 13 RC 12 RC 11 P1 P4 P2 P5 PLC B Port 3 PLC C To PLC C From PC 1 To RC 11 From PLC A Port 3 PLC C Port 2 RC 11 To RC 11 From PC 1 To PLC C From PLC 1 PLC C PLC A PLC B Operating mode of a Switch

Managed vs. Unmanaged Switches

Switches – unmanaged Device which delivers a received Uni-Cast data packet only to that port on which the destination station is connected. ALL switches on the network instantly recognize newly attached devices, read MAC address and records that into its address table (no manual configuration needed) RJ45 ports are typically 10/100 auto-sensing Multiple versions for variety of RJ45/Fiber port configurations

Switches – Managed Device which delivers a received Uni-Cast data packet only to that port on which the destination station is connected. ALL switches on the network instantly recognize newly attached devices, read MAC address and records that into its address table (no manual configuration needed) RJ45 ports are typically 10/100 auto-sensing Multiple versions for variety of RJ45/Fiber port configurations

Can be programmed using Serial, Web interface, or SNMP software Port security - Security functionality is important in terms of awareness and prevention of unwanted access to devices as well as the network as a whole. Port mirroring - necessary for accurate network diagnostic monitoring and troubleshooting by allowing you to copy the Unicasts traffic from one port to another. Multicast Filtering - provides for the proper management of IP multicast traffic. It ensures that not only Unicasts but multicast traffic is properly directed only where it is meant to go. Remote monitoring – Allows for the capability of remotely monitoring conditions and criteria of the "goings on" of the switch. Spanning Tree Protocol facilitates redundant back bone connections and loop free networks. Prioritization support, ensures that frames tagged with higher priority will be handled quickly and efficiently. Broadcast Limiters which allow the administrator to filter the amount of broadcast traffic on a packets per second per port basis. Managed Vs Non-Managed

Unicast traffic, through a hub, is like broadcast traffic Multicast traffic through a hub or “unmanaged Switch” is like broadcast traffic Broadcast traffic when not controlled, can affect overall network performance as well as your network nodes ability to perform its primary process causing “time outs” which lead to communication failures and ultimately process failure Remember the traffic?

Features Prevent collisions Auto-polarity, -sensing Auto-negotiation, -MDI/MDIX Web interface Port security Port mirroring Multicast Filtering/IGMP Remote monitoring Redundancy SNMP Broadcast Limiter ManagedUnmanaged Managed Vs Non-Managed

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