Users Guide

Viewing an ECMP Group
NOTE: An ecmp-group index is generated automatically for each unique ecmp-group when you
configure multipath routes to the same network. The system can generate a maximum of 512 unique
ecmp-groups. The ecmp-group indices are generated in even numbers (0, 2, 4, 6... 1022) and are for
information only.
You can configure ecmp-group with id 2 for link bundle monitoring. This ecmp-group is different from
the ecmp-group index 2 that is created by configuring routes and is automatically generated. These two
ecmp-groups are not related in any way.
Dell(conf-ecmp-group-5)#show config
!
ecmp-group 5
interface tengigabitethernet 1/2/1
interface tengigabitethernet 1/3/1
link-bundle-monitor enable
Dell(conf-ecmp-group-5)#
Support for /128 IPv6 and /32 IPv4 Prefixes in
Layer 3 Host Table and LPM Table
IPv6 enhancements utilize the capability on platform to program /128 IPv6 prefixes in LPM table and /32 IPv4
prefixes in Host table. Also host table provides ECMP support for destination prefixes in the hardware. The
platform uses the hardware chip that supports this behavior and hence they can make use of this capability.
CLI commands are introduced to move /128 IPv6 prefix route entries and /32 IPv4 prefix route entries from
Host table to LPM table and vice versa. When moving the destination prefixes from Route to Host table, there
is a possibility of getting into hash collision because the Host table on the device is a Hash table. In this
scenario, a workaround does not exist for the user having route entries programmed in host table.
When the command is issued, you are prompted with a warning message stating that the command
configuration can take effect on existing prefixes only when “clear ip route *” command is used. When you
use the clear command, all the existing /32 IPv4 prefix route entries are reprogrammed in appropriate table.
Also, all the other existing IPv4 entries are removed and reprogrammed as a result of the clear command.
Dell Networking OS releases earlier than Release 9.3(0.1) stores IPv6 /128 entries in Host table since it cannot
be written in LPM table, and IPv4 0/32 route entries are written in LPM table itself to support the ECMP since
ECMP was not supported in Host table. On the system, unified forwarding table (UFT) is enabled, and the host
table size is bigger compared to the LPM. When you move the IPv4 /32 route prefix entry in host table, more
space is obtained that can be utilized for other route prefix entries.
Support for ECMP in host table
ECMP support in the L3 host table is available on the system. IPv6 /128 prefix route entries and IPv4 /32 prefix
entries which are moved to host table can have ECMP. For other platforms, only the IPv6 /128 prefix route
entries is stored in the L3 host table without ECMP support.
The software supports a command to program IPv6 /128 route prefixes in the host table.
Equal Cost Multi-Path (ECMP) 334