Linksys SLM224G4S manual Advanced Stacking, Stack Resiliency, Unit IDs, Unit ID Allocation

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Appendix B

About Switch Stacking

the Console port, Telnet or Web-based Utility) and reset the units to make this assignment permanent.

The unit that is assigned number 1 will act as the Master; this is indicated by the Stack Master LED on its front panel being lit amber. The unit that is assigned number 2 will act as the Backup Master.

Stack Resiliency

A stack’s topology may be either Ring or Chain. The best practice is to configure the stack in Ring topology, due to its higher resiliency in case of unit failure or stacking link failure.

Additionally, if a redundant power supply is used, it is recommended to make sure that the Master and Backup Master units are connected to the redundant power supply.

Advanced Stacking

In order to understand the operation of the stack it is necessary to understand two key concepts:

•Unit IDs, and how they are allocated

•Stack unit start up process

Unit IDs

Each unit in a stack has an assigned unique Unit ID number. Unit ID numbers are meaningful as follows:

•The unit that is assigned Unit ID=1 will serve as the Stack Master. All other units will be stack members.

The stack Master provides a single point of control, configuration and management for the entire stack, and stores the configuration for all stack members (which themselves do not store any configuration information at all).

•The unit that is assigned Unit ID=2 is a special stack member, which serves as the Stack Backup Master.

A stack Backup Master, in addition to being a stack member, serves as a Backup in case the stack Master fails or is disconnected for any reason. If that should happen, the Backup Master takes over the role of stack Master for the remaining stack members.

To make this possible, the stack Master will store a copy of the active configuration on the Backup Master, but this copy will only be used if and when it takes over the role of stack Master. Note that only the configuration file is copied. Any dynamically filled tables, e.g. addresses learned, are not copied from the Master to the Backup Master. If the Backup Master takes over the role of stack Master, it will start building its own dynamic tables from scratch.

•Units that are assigned Unit IDs 3-6 (SLM224G4S) or Unit IDs 3-4 (SLM248G4S) are called Stack Members.

A stack member will only operate as a member of the stack under the direction of an operational stack Master (or a Backup Master that has taken over the role).

Stack members are not directly manageable and configurable, and must be managed through the stack Master, and do not contain any meaningful configuration information (not even their own configuration). If an operational master is not present and reachable, these units will not be functional.

•Master Enabled units

Units that are assigned a unit ID number of 1 or 2 are calledmasterenabledunits.Onlymasterenabledunits participate in master election (see below) whenever they are initiated, inserted into a new stack or lose connectivity with the existing master. Only master enabled units can become the stack master or backup master. Units with assigned IDs of 3-6 (SLM224G4S) or 3-4 (SLM248G4S) can become neither a master nor a backup master unless this is done manually by the system administrator or they are reset to the factory default first.

Unit ID Allocation

Units are shipped from the factory with no Unit ID, and must be assigned a unique Unit ID before they can operate as part of a stack. Unit ID numbers are assigned to units in one of two ways:

•Assigned by the system administrator, in which case they can only be changed manually by the system administrator

•Allocated to a stack member unit by the stack Master during system initialization

In general, a unit that was assigned a Unit ID will tend to keep this number even after it is rebooted. The stack Master may reallocate Unit IDs during system initialization to resolve duplicate Unit ID conflicts (see below). Manually assigned Unit IDs cannot be changed by the stack Master, even if they are in conflict.

Unit ID assignment/change takes effect only during system initialization and does not take place during run- time of the system.

Units of a stack do not have to be numbered in sequence or in order, and may be interconnected as desired, as long as each unit has a unique ID and at least one unit of the stack serves as stack Master.

24/48-Port 10/100 + 4-Port Gigabit Resilient Clustering Smart Switch with 2 Combo SFPs

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Contents Port or 48-Port 10/100 + About This Guide About This GuideIcon Descriptions Online ResourcesTable of Contents Snmp Appendix B About Switch Stacking Appendix C GlossaryGigabit Ethernet Fiber Optic Cabling Appendix G Contact Information Appendix D SpecificationsIntroduction ChapterProduct Overview Chapter Product OverviewFront Panel Back PanelSLM248G4S Installation Chapter InstallationPre-Installation Considerations Placement OptionsHardware Installation Desktop PlacementRack-Mount Placement Configuring Stacking Mode Uplinking the SwitchReplacing a Stacked Switch Connect port G1 on Unit 2 to port G2 on UnitConnect port G1 on Unit 3 to port G2 on Unit Using the HyperTerminal Application Chapter Configuration Using Console InterfaceUsing telnet Login screen appears. Proceed to the Login section belowLogin How to Use the Console InterfaceSwitch Main Menu System Configuration MenuManagement Settings User & Password SettingsSystem Information IP Configuration Security SettingsFile Management Network ConfigurationRestore System Default Settings Reboot SystemStack Configuration System Mode Port ConfigurationPort Status HelpSetup Chapter Configuration Using Web-based UtilitySetup Summary Device InformationSetup Network Settings Setup ZoomDefault Gateway The IP address default 0.0.0.0 DNS Server The IP address of your ISP’s server thatIdentification Setup TimeLocal Time Daylight SavingPort Management Port Settings Setup Stack ManagementPort Management Sntp ServersPort Configuration Port Management Link Aggregation LAG ConfigurationPort Management Lacp Lacp screen contains fields for configuring Lacp LAGsGlobal Parameter Port PriorityVlan Management Vlan Management Port SettingsVlan Management Create Vlan Lacp Port TableVlan Management Port to Vlan Vlan Management Vlan to PortJoin Vlan to Port Statistics Rmon Statistics StatisticsRmon History Statistics Rmon HistoryLog Table Rmon History TableAdd Alarm Statistics Rmon AlarmsStatistics Port Utilization Statistics Rmon EventsStatistics Interface Statistics Security Security 802.1x SettingsInterface Ethernet-likeSecurity Port Security Setting TimerWeb IP Filtering Security Management Access ListSecurity Storm Control Security RadiusBroadcast Only Counts only Broadcast traffic CoS Settings QoS CoS SettingsCoS Default CoS Settings screen is used to enable or disable CoSQoS Queue Settings QoS Dscp SettingsQoS Bandwidth QoS Basic Mode Spanning TreeSpanning Tree STP Status Global Setting Spanning Tree STP Port SettingsBridge Settings Spanning Tree Global STPMulticast Vlan Igmp SettingsMulticast Igmp Snooping Igmp GlobalMulticast Bridge Multicast Forward All Multicast Bridge MulticastSnmp Views Snmp Global ParametersSnmp Group Profile Snmp Group MembershipUser Name Provides a user-defined local user list Snmp Communities Snmp Notification Recipient Snmp Notification FilterBase Table Advanced TableAdmin User Authentication AdminUser Authentication Local User EditAdmin Dynamic Address Admin Static AddressSecure The entry is defined for locked ports Clear Table If selected, this clears the MAC Address tableAdmin Port Mirroring Admin Cable TestQuery Admin Save Configuration Admin Firmware Upgrade Admin RebootAdmin Factory Default Admin Logging Admin Server LogsAdmin Memory Logs Logout Admin Flash LogsAppendix a About Gigabit Ethernet Fiber Optic Cabling Appendix aGigabit Ethernet Fiber Optic CablingAbout Switch Stacking Appendix B About Switch StackingAppendix B Stack Building Quick StartStack Resiliency Advanced StackingUnit IDs Unit ID AllocationStack Units Startup Process Master DiscoveryMaster Election User Controls Unit and Port ConfigurationStacking Examples Replacing a Failed Stack Member in a Running StackStack Master Failure and Replacement Splitting a Stack Subgroup Contains Both Master Unit and Backup Master UnitBoth Stacks Kept Running During Insertion Merging Two StacksInserting Too Many Units Stacking Cable FailureAppendix C Appendix C GlossaryGlossary Glossary Mail protocol on the Internet Packet a unit of data sent over a networkAppendix C Appendix D Specifications SpecificationsAppendix D HOL Blocking Head of line blocking prevention DimensionsSupports up to 9K byte frames 802.3 10BASE-T EthernetLimited Warranty Warranty InformationObtaining Warranty Service Appendix ETechnical Support Warranty InformationRegulatory Information Appendix FRegulatory Information Appendix F Norsk Norwegian Miljøinformasjon for kunder i EU Appendix F Contact Information Appendix G

SLM224G4S specifications

The Linksys SLM224G4S is a sophisticated Layer 2 managed switch designed for businesses and institutions that demand high performance, reliability, and advanced networking features. This model stands out due to its blend of robustness and manageability, making it ideal for expanding networks.

One of the primary features of the SLM224G4S is its 24 Gigabit Ethernet ports, allowing for high-speed data transfers essential for bandwidth-intensive applications. Supporting auto-negotiation, these ports can detect the capabilities of connected devices and configure themselves accordingly, ensuring optimal performance without manual intervention. With four additional shared Gigabit SFP (Small Form-factor Pluggable) ports, this switch provides flexibility in network design and enhances scalability.

The SLM224G4S supports VLAN (Virtual Local Area Network) capabilities, which can segment network traffic to improve security and performance. This is particularly useful in environments where different departments or teams require distinct network segments for operational efficiency. By implementing VLANs, organizations can enhance their network management while isolating sensitive information from potential threats.

Quality of Service (QoS) is another critical technology integrated into the SLM224G4S. It prioritizes network traffic, ensuring that critical applications receive the bandwidth they need for optimal performance. This is particularly important for VoIP and video conferencing applications, where latency and jitter can significantly impact user experience.

The switch also features advanced Layer 2 management functionalities, including SNMP (Simple Network Management Protocol), allowing IT administrators to monitor network performance and quickly troubleshoot issues. The embedded web-based management interface makes configuration straightforward, enabling quick adjustments to settings without deep networking knowledge.

Security is a paramount consideration in today’s networking landscape. The SLM224G4S provides robust security features, including port security that limits the number of MAC addresses allowed on a port, reducing the risk of unauthorized access. Moreover, it supports802.1X port-based authentication, ensuring that only authenticated devices can connect to the network.

In summary, the Linksys SLM224G4S managed switch boasts features such as 24 Gigabit Ethernet ports, VLAN support, QoS, SNMP management, and advanced security protocols. These characteristics make it an excellent choice for businesses looking to enhance their network's performance, safety, and reliability, paving the way for seamless connectivity in today’s digital age.
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