Setup Guide

Table Of Contents
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 EMC 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.
The output of show IPv6 cam command has been enhanced to include the ECMP field in the Neighbor table of Ipv6 CAM. The sample
output is displayed as follows, which is similar to the prefix table.
The following is the portion of the example output:
Neighbor Mac-Addr Port Vid EC
------------------------------------- -------------------------
[ 132] 20::1 00:00:20:d5:ec:a0 Fo 1/49/1 0 1
[ 132] 20::1 00:00:20:d5:ec:a1 Fo 1/50/1 0 1
Support for moving /128 IPv6 Prefixes and /32 IPv4
Prefixes
The software supports a command to program IPv6 /128 route prefixes in the route table. You can define IPv6 /128 route prefixes in the
route table using the ipv6 unicast-host-routecommand. You can also define IPv4 /32 route prefixes in the host table using the
ipv4 unicast-host-routecommand.
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Equal Cost Multi-Path (ECMP)