Cisco ECMP

BGP defaults to 1 path.

OSPF defaults to 4 paths.

EIGRP defaults to 4 paths.

ECMP Algorithms

Your equipment might support different options.

Universal

• Default
• Selects based on (src-ip, dst-ip)

Original

• Legacy
• Exists on Cisco equipment

Tunnel

• Meant for tunnel endpoints
• Help with with low src-ip and dst-ip diversity

Include Ports

• Selects based on longer tuple
  • (src-ip, dst-ip, src-port, dst-port)

ip cef load-sharing algorithm

References

IP Switching: Cisco Express Forwarding - Configuring a Load-Balancing Scheme for Cisco Express Forwarding Traffic Support - Cisco

IP Switching Cisco Express Forwarding Configuration Guide - Configuring a Load-Balancing Scheme Cisco ASR 1000 Series Aggregation Services Routers - Cisco