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Table Of Contents
- Dell Networking Configuration Guide for the Z9500 Switch 9.13.0.0
- About this Guide
- Configuration Fundamentals
- Getting Started
- Console Access
- Default Configuration
- Configuring a Host Name
- Accessing the System Remotely
- Configuring the Enable Password
- Configuration File Management
- Enabling Software Features on Devices Using a Command Option
- View Command History
- Upgrading Dell EMC Networking OS
- Verify Software Images Before Installation
- Management
- Configuring Privilege Levels
- Configuring Logging
- Track Login Activity
- Limit Concurrent Login Sessions
- Enabling Secured CLI Mode
- Log Messages in the Internal Buffer
- Disabling System Logging
- Sending System Messages to a Syslog Server
- Display the Logging Buffer and the Logging Configuration
- Changing System Logging Settings
- Configuring a UNIX Logging Facility Level
- Synchronizing Log Messages
- Enabling Timestamp on Syslog Messages
- File Transfer Services
- Terminal Lines
- Setting Timeout for EXEC Privilege Mode
- Using Telnet to get to Another Network Device
- Lock CONFIGURATION Mode
- Recovering from a Forgotten Password on the Z9000 System
- Ignoring the Startup Configuration and Booting from the Factory-Default Configuration
- Recovering from a Failed Start on the Z9000 System
- Restoring the Factory Default Settings
- Viewing the Reason for Last System Reboot
- 802.1X
- Port-Authentication Process
- Configuring 802.1X
- Important Points to Remember
- Enabling 802.1X
- Configuring dot1x Profile
- Configuring the Static MAB and MAB Profile
- Configuring Critical VLAN
- Configuring MAC addresses for a do1x Profile
- Configuring Request Identity Re-Transmissions
- Forcibly Authorizing or Unauthorizing a Port
- Re-Authenticating a Port
- Configuring Timeouts
- Configuring Dynamic VLAN Assignment with Port Authentication
- Guest and Authentication-Fail VLANs
- Access Control Lists (ACLs)
- IP Access Control Lists (ACLs)
- IP Fragment Handling
- Configure a Standard IP ACL
- Configure an Extended IP ACL
- Configure Layer 2 and Layer 3 ACLs
- Using ACL VLAN Groups
- Applying an IP ACL
- IP Prefix Lists
- ACL Resequencing
- Route Maps
- Important Points to Remember
- Configuring UDF ACL
- Configuring IP Mirror Access Group
- Bare Metal Provisioning (BMP)
- Bidirectional Forwarding Detection (BFD)
- Border Gateway Protocol IPv4 (BGPv4)
- Autonomous Systems (AS)
- Sessions and Peers
- Route Reflectors
- BGP Attributes
- Multiprotocol BGP
- Implement BGP with Dell EMC Networking OS
- Configuration Information
- BGP Configuration
- Enabling BGP
- Configuring AS4 Number Representations
- Configuring Peer Groups
- Configuring BGP Fast Fall-Over
- Configuring Passive Peering
- Maintaining Existing AS Numbers During an AS Migration
- Allowing an AS Number to Appear in its Own AS Path
- Enabling Neighbor Graceful Restart
- Filtering on an AS-Path Attribute
- Regular Expressions as Filters
- Redistributing Routes
- Enabling Additional Paths
- Configuring IP Community Lists
- Configuring an IP Extended Community List
- Filtering Routes with Community Lists
- Manipulating the COMMUNITY Attribute
- Changing MED Attributes
- Changing the LOCAL_PREFERENCE Attribute
- Configuring the local System or a Different System to be the Next Hop for BGP-Learned Routes
- Changing the WEIGHT Attribute
- Enabling Multipath
- Filtering BGP Routes
- Filtering BGP Routes Using Route Maps
- Filtering BGP Routes Using AS-PATH Information
- Configuring BGP Route Reflectors
- Aggregating Routes
- Configuring BGP Confederations
- Enabling Route Flap Dampening
- Changing BGP Timers
- Enabling BGP Neighbor Soft-Reconfiguration
- Enabling or disabling BGP neighbors
- Route Map Continue
- Enabling MBGP Configurations
- BGP Regular Expression Optimization
- Debugging BGP
- Sample Configurations
- Content Addressable Memory (CAM)
- Control Plane Policing (CoPP)
- Data Center Bridging (DCB)
- Ethernet Enhancements in Data Center Bridging
- Priority-Based Flow Control
- Enhanced Transmission Selection
- Data Center Bridging Exchange Protocol (DCBx)
- Enabling Data Center Bridging
- Data Center Bridging: Default Configuration
- Configuring Priority-Based Flow Control
- Configuring PFC in a DCB Map
- Applying a DCB Map on a Port
- Configuring PFC without a DCB Map
- Priority-Based Flow Control Using Dynamic Buffer Method
- Behavior of Tagged Packets
- Operations on Untagged Packets
- Configuration Example for DSCP and PFC Priorities
- SNMP Support for PFC and Buffer Statistics Tracking
- Generation of PFC for a Priority for Untagged Packets
- Performing PFC Using DSCP Bits Instead of 802.1p Bits
- PFC and ETS Configuration Examples
- Using PFC to Manage Converged Ethernet Traffic
- Configure Enhanced Transmission Selection
- Hierarchical Scheduling in ETS Output Policies
- Applying the DCB Policies on Linecard
- Applying DCB Policies on SFM Ports
- Using ETS to Manage Converged Ethernet Traffic
- Configure a DCBx Operation
- Verifying the DCB Configuration
- QoS dot1p Traffic Classification and Queue Assignment
- Configuring the Dynamic Buffer Method
- Sample DCB Configuration
- Debugging and Diagnostics
- Dynamic Host Configuration Protocol (DHCP)
- DHCP Packet Format and Options
- Assign an IP Address using DHCP
- Implementation Information
- Configure the System to be a DHCP Server
- Configure the System to be a Relay Agent
- Configure the System to be a DHCP Client
- Configure Secure DHCP
- Option 82
- DHCP Snooping
- Enabling DHCP Snooping
- Enabling IPv6 DHCP Snooping
- Adding a Static Entry in the Binding Table
- Adding a Static IPV6 DHCP Snooping Binding Table
- Clearing the Binding Table
- Clearing the DHCP IPv6 Binding Table
- Displaying the Contents of the Binding Table
- Displaying the Contents of the DHCPv6 Binding Table
- Debugging the IPv6 DHCP
- IPv6 DHCP Snooping MAC-Address Verification
- Configuring the DHCP secondary-subnet
- Drop DHCP Packets on Snooped VLANs Only
- Dynamic ARP Inspection
- Configuring Dynamic ARP Inspection
- Source Address Validation
- Equal Cost Multi-Path (ECMP)
- FIP Snooping
- Fibre Channel over Ethernet
- Ensure Robustness in a Converged Ethernet Network
- FIP Snooping on Ethernet Bridges
- Using FIP Snooping
- FIP Snooping Prerequisites
- Important Points to Remember
- Enabling the FCoE Transit Feature
- Enable FIP Snooping on VLANs
- Configure the FC-MAP Value
- Configure a Port for a Bridge-to-Bridge Link
- Configure a Port for a Bridge-to-FCF Link
- Impact on Other Software Features
- FIP Snooping Restrictions
- Configuring FIP Snooping
- FCoE Transit Configuration Example
- Displaying FIP Snooping Information
- FIPS Cryptography
- Flex Hash
- Force10 Resilient Ring Protocol (FRRP)
- GARP VLAN Registration Protocol (GVRP)
- Internet Group Management Protocol (IGMP)
- Interfaces
- Port Numbering Convention
- Interface Types
- View Basic Interface Information
- Resetting an Interface to its Factory Default State
- Enabling a Physical Interface
- Physical Interfaces
- Egress Interface Selection (EIS)
- Management Interfaces
- VLAN Interfaces
- Loopback Interfaces
- Null Interfaces
- Port Channel Interfaces
- Port Channel Definition and Standards
- Port Channel Benefits
- Port Channel Implementation
- Interfaces in Port Channels
- Configuration Tasks for Port Channel Interfaces
- Creating a Port Channel
- Adding a Physical Interface to a Port Channel
- Reassigning an Interface to a New Port Channel
- Configuring the Minimum Oper Up Links in a Port Channel
- Adding or Removing a Port Channel from a VLAN
- Assigning an IP Address to a Port Channel
- Deleting or Disabling a Port Channel
- Load Balancing Through Port Channels
- Changing the Hash Algorithm
- Bulk Configuration
- Defining Interface Range Macros
- Monitoring and Maintaining Interfaces
- Displaying Traffic Statistics on HiGig Ports
- Link Bundle Monitoring
- Monitoring HiGig Link Bundles
- Non Dell-Qualified Transceivers
- Splitting 40G Ports without Reload
- Splitting QSFP Ports to SFP+ Ports
- Configuring wavelength for 10–Gigabit SFP+ optics
- Link Dampening
- Using Ethernet Pause Frames for Flow Control
- Configure the MTU Size on an Interface
- Auto-Negotiation on Ethernet Interfaces
- View Advanced Interface Information
- Configuring the Traffic Sampling Size Globally
- Dynamic Counters
- Internet Protocol Security (IPSec)
- IPv4 Routing
- IP Addresses
- Configuration Tasks for IP Addresses
- Assigning IP Addresses to an Interface
- Configuring Static Routes
- Configure Static Routes for the Management Interface
- Enabling Directed Broadcast
- Resolution of Host Names
- Enabling Dynamic Resolution of Host Names
- Specifying the Local System Domain and a List of Domains
- Configuring DNS with Traceroute
- ARP
- Configuration Tasks for ARP
- Configuring Static ARP Entries
- Enabling Proxy ARP
- Clearing ARP Cache
- ARP Learning via Gratuitous ARP
- Enabling ARP Learning via Gratuitous ARP
- ARP Learning via ARP Request
- Configuring ARP Retries
- ICMP
- Configuration Tasks for ICMP
- Enabling ICMP Unreachable Messages
- UDP Helper
- Enabling UDP Helper
- Configuring a Broadcast Address
- Configurations Using UDP Helper
- UDP Helper with Broadcast-All Addresses
- UDP Helper with Subnet Broadcast Addresses
- UDP Helper with Configured Broadcast Addresses
- UDP Helper with No Configured Broadcast Addresses
- Troubleshooting UDP Helper
- IPv6 Routing
- Protocol Overview
- Implementing IPv6 with Dell EMC Networking OS
- Longest Prefix Match (LPM) Table and IPv6 /65 – /128 support
- ICMPv6
- Path MTU Discovery
- IPv6 Neighbor Discovery
- Secure Shell (SSH) Over an IPv6 Transport
- Configuration Tasks for IPv6
- Adjusting Your CAM-Profile
- Assigning an IPv6 Address to an Interface
- Assigning a Static IPv6 Route
- Configuring Telnet with IPv6
- SNMP over IPv6
- Displaying IPv6 Information
- Displaying an IPv6 Interface Information
- Showing IPv6 Routes
- Showing the Running-Configuration for an Interface
- Clearing IPv6 Routes
- Disabling ND Entry Timeout
- Configuring IPv6 RA Guard
- iSCSI Optimization
- iSCSI Optimization Overview
- Default iSCSI Optimization Values
- iSCSI Optimization Prerequisites
- Configuring iSCSI Optimization
- Displaying iSCSI Optimization Information
- Enable and Disable iSCSI Optimization
- Synchronizing iSCSI Sessions Learned on VLT-Lags with VLT-Peer
- Monitoring iSCSI Traffic Flows
- Information Monitored in iSCSI Traffic Flows
- Detection and Auto-Configuration for Dell EqualLogic Arrays
- Configuring Detection and Ports for Dell Compellent Arrays
- Application of Quality of Service to iSCSI Traffic Flows
- Intermediate System to Intermediate System
- IS-IS Protocol Overview
- IS-IS Addressing
- Multi-Topology IS-IS
- Graceful Restart
- Implementation Information
- Configuration Information
- IS-IS Metric Styles
- Configure Metric Values
- Sample Configurations
- Link Aggregation Control Protocol (LACP)
- Layer 2
- Link Layer Discovery Protocol (LLDP)
- 802.1AB (LLDP) Overview
- Optional TLVs
- TIA-1057 (LLDP-MED) Overview
- Configure LLDP
- CONFIGURATION versus INTERFACE Configurations
- Enabling LLDP
- Enabling LLDP on Management Ports
- Advertising TLVs
- Storing and Viewing Unrecognized LLDP TLVs
- Viewing the LLDP Configuration
- Viewing Information Advertised by Adjacent LLDP Neighbors
- Configuring LLDPDU Intervals
- Configuring LLDP Notification Interval
- Configuring Transmit and Receive Mode
- Configuring the Time to Live Value
- Debugging LLDP
- Relevant Management Objects
- Microsoft Network Load Balancing
- Multicast Source Discovery Protocol (MSDP)
- Anycast RP
- Implementation Information
- Configure Multicast Source Discovery Protocol
- Enable MSDP
- Manage the Source-Active Cache
- Accept Source-Active Messages that Fail the RFP Check
- Specifying Source-Active Messages
- Limiting the Source-Active Messages from a Peer
- Preventing MSDP from Caching a Local Source
- Preventing MSDP from Caching a Remote Source
- Preventing MSDP from Advertising a Local Source
- Logging Changes in Peership States
- Terminating a Peership
- Clearing Peer Statistics
- Debugging MSDP
- MSDP with Anycast RP
- Configuring Anycast RP
- MSDP Sample Configurations
- Multiple Spanning Tree Protocol (MSTP)
- Spanning Tree Variations
- Configure Multiple Spanning Tree Protocol
- Enable Multiple Spanning Tree Globally
- Adding and Removing Interfaces
- Creating Multiple Spanning Tree Instances
- Influencing MSTP Root Selection
- Interoperate with Non-Dell Bridges
- Changing the Region Name or Revision
- Modifying Global Parameters
- Modifying the Interface Parameters
- Configuring an EdgePort
- Flush MAC Addresses after a Topology Change
- MSTP Sample Configurations
- Debugging and Verifying MSTP Configurations
- Multicast Features
- Open Shortest Path First (OSPFv2 and OSPFv3)
- Protocol Overview
- OSPF with Dell EMC Networking OS
- Configuration Information
- Configuration Task List for OSPFv2 (OSPF for IPv4)
- Enabling OSPFv2
- Assigning a Router ID
- Assigning an OSPFv2 Area
- Enable OSPFv2 on Interfaces
- Configuring Stub Areas
- Configuring LSA Throttling Timers
- Enabling Passive Interfaces
- Enabling Fast-Convergence
- Changing OSPFv2 Parameters on Interfaces
- Enabling OSPFv2 Authentication
- Configuring Virtual Links
- Creating Filter Routes
- Applying Prefix Lists
- Redistributing Routes
- Troubleshooting OSPFv2
- Sample Configurations for OSPFv2
- Configuration Task List for OSPFv2 (OSPF for IPv4)
- OSPFv3 NSSA
- Configuration Task List for OSPFv3 (OSPF for IPv6)
- Enabling IPv6 Unicast Routing
- Applying cost for OSPFv3
- Assigning IPv6 Addresses on an Interface
- Assigning Area ID on an Interface
- Assigning OSPFv3 Process ID and Router ID Globally
- Configuring Stub Areas
- Configuring Passive-Interface
- Redistributing Routes
- Configuring a Default Route
- OSPFv3 Authentication Using IPsec
- Troubleshooting OSPFv3
- Pay As You Grow
- PIM Sparse-Mode (PIM-SM)
- PIM Source-Specific Mode (PIM-SSM)
- Policy-based Routing (PBR)
- Port Monitoring
- Private VLANs (PVLAN)
- Per-VLAN Spanning Tree Plus (PVST+)
- Protocol Overview
- Implementation Information
- Configure Per-VLAN Spanning Tree Plus
- Enabling PVST+
- Disabling PVST+
- Influencing PVST+ Root Selection
- Modifying Global PVST+ Parameters
- Modifying Interface PVST+ Parameters
- Configuring an EdgePort
- PVST+ in Multi-Vendor Networks
- Enabling PVST+ Extend System ID
- PVST+ Sample Configurations
- Quality of Service (QoS)
- Implementation Information
- Port-Based QoS Configurations
- Policy-Based QoS Configurations
- DSCP Color Maps
- Enabling QoS Rate Adjustment
- Enabling Strict-Priority Queueing
- Weighted Random Early Detection
- Explicit Congestion Notification
- Configuring Weights and ECN for WRED
- Pre-Calculating Available QoS CAM Space
- SNMP Support for Buffer Statistics Tracking
- Enabling Buffer Statistics Tracking
- Routing Information Protocol (RIP)
- Remote Monitoring (RMON)
- Rapid Spanning Tree Protocol (RSTP)
- Protocol Overview
- Configuring Rapid Spanning Tree
- Important Points to Remember
- Configuring Interfaces for Layer 2 Mode
- Enabling Rapid Spanning Tree Protocol Globally
- Adding and Removing Interfaces
- Modifying Global Parameters
- Modifying Interface Parameters
- Influencing RSTP Root Selection
- Configuring an EdgePort
- Configuring Fast Hellos for Link State Detection
- Security
- Role-Based Access Control
- AAA Accounting
- AAA Authentication
- Obscuring Passwords and Keys
- AAA Authorization
- RADIUS
- RADIUS Authentication
- Configuration Task List for RADIUS
- Support for Change of Authorization and Disconnect Messages packets
- Change of Authorization (CoA) packets
- Disconnect Messages
- Attributes
- Error-cause Values
- CoA Packet Processing
- CoA or DM Discard
- Disconnect Message Processing
- Configuring DAC
- Configuring the port number
- Configuring shared key
- Disconnecting administrative users logged in through RADIUS
- Configuring CoA to bounce 802.1x enabled ports
- Configuring CoA to re-authenticate 802.1x sessions
- Terminating the 802.1x user session
- Disabling 802.1x enabled port
- Important points to remember
- Configuring replay protection
- Rate-limiting RADIUS packets
- Configuring time-out value
- TACACS+
- Protection from TCP Tiny and Overlapping Fragment Attacks
- Enabling SCP and SSH
- Using SCP with SSH to Copy a Software Image
- Removing the RSA Host Keys and Zeroizing Storage
- Configuring When to Re-generate an SSH Key
- Configuring the SSH Server Cipher List
- Configuring the HMAC Algorithm for the SSH Server
- Configuring the HMAC Algorithm for the SSH Client
- Configuring the SSH Server Cipher List
- Configuring the SSH Client Cipher List
- Secure Shell Authentication
- Troubleshooting SSH
- Telnet
- VTY Line and Access-Class Configuration
- Two Factor Authentication (2FA)
- Configuring the System to Drop Certain ICMP Reply Messages
- Dell EMC Networking OS Security Hardening
- Service Provider Bridging
- sFlow
- Simple Network Management Protocol (SNMP)
- Protocol Overview
- Implementation Information
- Configuration Task List for SNMP
- Important Points to Remember
- Set up SNMP
- Reading Managed Object Values
- Writing Managed Object Values
- Configuring Contact and Location Information using SNMP
- Subscribing to Managed Object Value Updates using SNMP
- Enabling a Subset of SNMP Traps
- Enabling an SNMP Agent to Notify Syslog Server Failure
- Copy Configuration Files Using SNMP
- Copying a Configuration File
- Copying Configuration Files via SNMP
- Copying the Startup-Config Files to the Running-Config
- Copying the Startup-Config Files to the Server via FTP
- Copying the Startup-Config Files to the Server via TFTP
- Copy a Binary File to the Startup-Configuration
- Additional MIB Objects to View Copy Statistics
- Obtaining a Value for MIB Objects
- MIB Support to Display Reason for Last System Reboot
- MIB Support for Power Monitoring
- MIB Support to Display the Available Memory Size on Flash
- MIB Support to Display the Software Core Files Generated by the System
- SNMP Support for WRED Green/Yellow/Red Drop Counters
- MIB Support to Display the Available Partitions on Flash
- MIB Support to Display Egress Queue Statistics
- MIB Support to ECMP Group Count
- MIB Support for entAliasMappingTable
- MIB Support for LAG
- MIB Support to Display Unrecognized LLDP TLVs
- Manage VLANs using SNMP
- Managing Overload on Startup
- Enabling and Disabling a Port using SNMP
- Fetch Dynamic MAC Entries using SNMP
- Deriving Interface Indices
- Monitoring BGP sessions via SNMP
- Monitor Port-Channels
- Troubleshooting SNMP Operation
- Transceiver Monitoring
- Storm Control
- Spanning Tree Protocol (STP)
- Protocol Overview
- Configure Spanning Tree
- Important Points to Remember
- Configuring Interfaces for Layer 2 Mode
- Enabling Spanning Tree Protocol Globally
- Adding an Interface to the Spanning Tree Group
- Modifying Global Parameters
- Modifying Interface STP Parameters
- Enabling PortFast
- Prevent Network Disruptions with BPDU Guard
- Selecting STP Root
- STP Root Guard
- Enabling SNMP Traps for Root Elections and Topology Changes
- STP Loop Guard
- Displaying STP Guard Configuration
- SupportAssist
- System Time and Date
- Tunneling
- Upgrade Procedures
- Uplink Failure Detection (UFD)
- Virtual LANs (VLANs)
- Virtual Routing and Forwarding (VRF)
- Virtual Link Trunking (VLT)
- Overview
- Configure Virtual Link Trunking
- RSTP Configuration
- Preventing Forwarding Loops in a VLT Domain
- Sample RSTP Configuration
- Configuring VLT
- Configuring a VLT Interconnect
- Enabling VLT and Creating a VLT Domain
- Configuring a VLT Backup Link
- Configuring a VLT Port Delay Period
- Reconfiguring the Default VLT Settings (Optional)
- Connecting a VLT Domain to an Attached Access Device (Switch or Server)
- Configuring a VLT VLAN Peer-Down (Optional)
- Configuring Enhanced VLT (Optional)
- VLT Sample Configuration
- PVST+ Configuration
- Peer Routing Configuration Example
- eVLT Configuration Example
- PIM-Sparse Mode Configuration Example
- Verifying a VLT Configuration
- Additional VLT Sample Configurations
- Troubleshooting VLT
- Specifying VLT Nodes in a PVLAN
- Configuring a VLT VLAN or LAG in a PVLAN
- Proxy ARP Capability on VLT Peer Nodes
- VLT Nodes as Rendezvous Points for Multicast Resiliency
- Configuring VLAN-Stack over VLT
- IPv6 Peer Routing in VLT Domains Overview
- VLT Proxy Gateway
- Virtual Router Redundancy Protocol (VRRP)
- VRRP Overview
- VRRP Benefits
- VRRP Implementation
- VRRP Configuration
- Configuration Task List
- Creating a Virtual Router
- Configuring the VRRP Version for an IPv4 Group
- Assign Virtual IP addresses
- Configuring a Virtual IP Address
- Setting VRRP Group (Virtual Router) Priority
- Configuring VRRP Authentication
- Disabling Preempt
- Changing the Advertisement Interval
- Track an Interface or Object
- Tracking an Interface
- Setting VRRP Initialization Delay
- Configuration Task List
- Sample Configurations
- Standards Compliance
- X.509v3
- Introduction to X.509v3 certification
- X.509v3 support in
- Information about installing CA certificates
- Information about Creating Certificate Signing Requests (CSR)
- Information about installing trusted certificates
- Transport layer security (TLS)
- Online Certificate Status Protocol (OSCP)
- Verifying certificates
- Event logging
Microsoft Network Load Balancing
Network Load Balancing (NLB) is a clustering functionality that is implemented by Microsoft on Windows 2000 Server and
Windows Server 2003 operating systems. Microsoft NLB clustering allows multiple servers running Microsoft Windows to be
represented by one MAC and one IP address to provide transparent failover and load-balancing. The Dell Networking OS does
not recognize server clusters by default; you must configure NLB functionality on a switch to support server clusters.
Topics:
• NLB Unicast and Multicast Modes
• NLB Benefits
• NLB Restrictions
• NLB VLAN Flooding
• Configuring NLB on a Switch
NLB Unicast and Multicast Modes
On a switch, you can configure NLB functionality to operate in two modes: unicast and multicast mode.
The server-cluster IP address and the associated cluster MAC address are configured in the NLB application running on the
Windows Server.
● In unicast mode, when the server IP address is resolved to the MAC address using the ARP application, the switch
determines whether the ARP reply obtained from the server is of an NLB type. The switch then maps the IP address (cluster
IP) with the MAC address (cluster MAC address).
● In multicast mode, the cluster IP address is mapped to a cluster multicast MAC address that is configured using a static
ARP CLI configuration command. After the NLB entry is learned, the traffic is forwarded to all the servers in the VLAN
corresponding to the cluster virtual IP address.
NLB Unicast Mode Example
Consider a sample topology in which four servers, namely S1 through S4, are configured as a cluster or a farm. This set
of servers is connected to a Layer 3 switch, which in turn is connected to the end-clients. The servers contain a single IP
address (IP-cluster address of 172.16.2.20) and a single unicast MAC address (MAC-Cluster address of 00-bf-ac-10-00-01)
for load-balancing. Because multiple ports of a switch cannot learn a single MAC address, the servers are assigned with MAC
addresses of MAC-s1 to MAC-s4) respectively on S1 through S4 in addition to the MAC cluster address. All the servers of the
cluster belong to the VLAN named VLAN1.
In unicast NLB mode, the following sequence of events occurs:
● The switch sends an ARP request to resolve the IP address to the cluster MAC address.
● The ARP servers send an ARP response with the MAC cluster address in the ARP header and a MAC address of MAC-
s1/s2/s3/s4 (for servers S1 through S4) in the Ethernet header.
● The switch associates the IP address with the MAC cluster address with the last ARP response it obtains. Assume that in
this case, the last ARP reply is obtained from MAC-s4.(assuming that the ARP response with MAC-s4 is received as the last
one). The interface associated with server, S4, is added to the ARP table.
● After the NLB ARP entry is learned on a switch when NLB enabled, all subsequent traffic is flooded on all ports in VLAN1.
With NLB, the data frame is forwarded to all servers in the cluster for the servers to perform load-balancing.
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Microsoft Network Load Balancing 513