• SonicOS 7.1 Rules and Policies
• Overview
  • About SonicOS
  • SonicOS Workflow
  • How to Use the SonicOS Administration Guides
  • Guide Conventions
• Settings
  • Configuring App/Match/Malware
  • Configuring Content Filtering Service (CFS)
    • SonicWall CFS
    • CFS Custom Category
  • Geo-IP
    • Custom List
      • Editing a Custom List Entry
      • Deleting Custom List Entries
    • Using Geo-IP Diagnostics
  • Botnet
    • Configuring Botnet Settings
    • Creating Custom Botnet Lists
    • Viewing Dynamic Botnets Lists
    • Configuring a Dynamic Botnet List Server
    • Using Botnet Diagnostics
  • Decryption (DPI-SSL)
    • Certificate
    • Common Name
    • SSL Servers
  • Decryption (DPI-SSH)
  • Signature Update
• Security Policy
  • User & Country
  • App/URL/Custom Match
• NAT Policy
  • About NAT in SonicOS
  • About NAT Load Balancing
    • Determining the NAT LB Method to Use
    • Caveats
    • How Load Balancing Algorithms are Applied
    • Sticky IP Algorithm Examples
      • Example One - Mapping to a Network
      • Example Two - Mapping to an IP Address Range
  • About NAT64
    • Use of Pref64::/n
  • About FQDN-based NAT
  • About Source MAC Address Override
  • Viewing NAT Policy Entries
    • Changing the Display
    • Filtering the Display
  • Adding or Editing NAT or NAT64 Rule Policies
  • Deleting NAT Policies
  • Creating NAT Rule Policies: Examples
    • Creating a One-to-One NAT Policy for Inbound Traffic
    • Creating a One-to-One NAT Policy for Outbound Traffic
    • Inbound Port Address Translation via One-to-One NAT Policy
    • Inbound Port Address Translation via WAN IP Address
    • Creating a Many-to-One NAT Policy
    • Creating a Many-to-Many NAT Policy
    • Creating a NAT Load Balancing Policy for Two Web Servers
• Routing
  • About Routing
    • About Metrics and Administrative Distance
      • About Metrics
      • About Administrative Distance
    • Route Advertisement
    • ECMP Routing
    • Policy-based Routing
    • Policy-based TOS Routing
    • PBR Metric-based Priority
    • Policy-based Routing and IPv6
    • OSPF and RIP Advanced Routing Services
      • About Routing Services
        • Protocol Type
        • Maximum Hops
        • Split-Horizon
        • Poison Reverse
        • Routing Table Updates
        • Subnet Sizes Supported
        • Autonomous System Topologies
      • OSPF Terms
    • Drop Tunnel Interface
    • App-based Routing
  • Rules and Policies >
    • Configuring
      • Adding Static Routes
      • Probe-Enabled Policy-based Routing Configuration
• Decryption Policy
  • Client-side SSL Rules
  • Server-side SSL Rules
  • SSH Rules
  • Setting up the Decryption Policy Table
    • Managing the Decryption Policy Toolbars
    • Changing the Policy Priority
    • Creating Decryption Policies
      • Adding Decryption Policies
      • Editing Decryption Policies
      • Deleting Decryption Policies
• DoS Policy
  • Setting up the DoS Policy Table
    • Managing the DoS Policy Toolbars
    • Changing the DoS Policy Priority
    • Creating DoS Policies
      • Adding DoS Policies
      • Editing DoS Policies
      • Deleting DoS Policies
• DNS Policy
  • Creating DNS Policies
    • Adding DNS Policies
    • Editing DNS Policies
    • Deleting DNS Policies
  • DNS Doctoring
• Endpoint Policy
• Shadow
• SonicWall Support
  • About This Document

ECMP Routing

SonicOS supports equal-cost multi-path (ECMP) routing, a technique for routing packets along multiple paths of equal cost. The forwarding engine identifies paths by next-hop. When forwarding a packet, the router must decide which next-hop (path) to use. Multi-path routing can be used in conjunction with most routing protocols.

In SonicOS, you can use ECMP routing to specify multiple next hops for a given route's destination. In environments with substantial requirements, there are several reasons for doing this. A router could just use one ISP most of the time, and switch to the other when the first one fails for some reason. Another application of multi-path is to keep a path on standby and enable it only when bandwidth requirements surpass a predefined threshold. SonicOS supports up to four next-hop paths.

Various routing protocols, including Open Shortest Path First (OSPF) and Intermediate System to Intermediate System (ISIS), explicitly allow ECMP routing. Some router implementations also allow equal-cost multi-path usage with RIP and other routing protocols.