Specifications

190 Implementing IBM System Networking 10Gb Ethernet Switches
Run no ip route <IP subnet> <IP netmask> [<interface number>] to remove a static route.
The destination address of the route to remove must be specified by using dotted
decimal notation.
Run no ip route destination-address <IP address> to clear all static routes with the
specified destination.
Run no ip route gateway <IP address> to clear all static routes that use the
specified gateway.
Equal-Cost Multi-Path static routes
Equal-Cost Multi-Path (ECMP) static routes are not used in the reference architecture. We
use dynamic routing protocol (OSPF) instead. This section shows basic configuration
commands and concepts for completeness. For more details, see 5.5, “More information” on
page 238.
ECMP is a forwarding mechanism that routes packets along multiple paths of equal cost.
ECMP provides equal-distributed link load sharing across the paths. The hashing algorithm
used is based on the source IP address (SIP). ECMP routes allow the switch to choose
between several next hops toward a destination. The switch performs periodic health checks
(ping) on each ECMP gateway. If a gateway fails, it is removed from the routing table, and an
SNMP trap is sent.
To configure ECMP static routes, add the same route multiple times, each with the same
destination IP address, but with a different gateway IP address. These routes become
ECMP routes. You can use two methods:
򐂰 OSPF integration: When a dynamic route is added through Open Shortest Path First
(OSPF), the switch checks the route’s gateway against the ECMP static routes. If the
gateway matches one of the single or ECMP static route destinations, then the OSPF
route is added to the list of ECMP static routes. Traffic is load-balanced across all of the
available gateways. When the OSPF dynamic route times out, it is deleted from the list of
ECMP static routes.
򐂰 ECMP route hashing: You can configure the parameters used to perform ECMP route
hashing as follows:
– sip: Source IP address (default)
– dipsip: Source IP address and destination IP address
sip and dipsip options: The sip and dipsip options enabled under ECMP route hashing
or in port trunk hashing (portchannel hash) apply to both ECMP and trunk features (the
enabled settings are cumulative). If unexpected ECMP route hashing occurs, disable the
unwanted source or destination IP address option set in trunk hashing. Likewise, if
unexpected trunk hashing occurs, disable any unwanted options set in ECMP
route hashing.
Hash setting: The ECMP hash setting applies to all ECMP routes.