Users Guide

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 conguration can take eect on
existing prexes only when “clear ip route *” command is used. When you use the clear command, all the existing /32 IPv4 prex 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,
unied forwarding table (UFT) is enabled, and the host table size is bigger compared to the LPM. When you move the IPv4 /32 route
prex entry in host table, more space is obtained that can be utilized for other route prex entries.
Support for ECMP in host table
ECMP support in the L3 host table is available on the system. IPv6 /128 prex route entries and IPv4 /32 prex entries which are moved to
host table can have ECMP. For other platforms, only the IPv6 /128 prex route entries is stored in the L3 host table without ECMP
support.
The software supports a command to program IPv6 /128 route prexes in the host table.
The output of show IPv6 cam command has been enhanced to include the ECMP eld in the Neighbor table of Ipv6 CAM. The sample
output is displayed as follows, which is similar to the prex 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 1/4 0 1
[ 132] 20::1 00:00:20:d5:ec:a1 Fo 1/8 0 1
Support for moving /128 IPv6 Prexes and /32 IPv4 Prexes
The software supports a command to program IPv6 /128 route prexes in the route table. You can dene IPv6 /128 route prexes in the
route table using the ipv6 unicast-host-routecommand. You can also dene IPv4 /32 route prexes in the host table using the
ipv4 unicast-host-routecommand.
RTAG7
RTAG7 is a hashing algorithm that load balances the trac within a trunk group in a controlled manner. In order to eectively increase the
bandwidth of the LAG/Equal Cost Multiple Path routes, trac is balanced across the member links. The balancing is performed by using
the RTAG7 hashing, which is designed to have the member links used eciently as the trac prole gets more diverse.Hashing-based load
balancing is used in the following applications:
• L3 ECMP
• LAGs
• HiGig trunking
The RTAG7 hash scheme generates a hash that consists of the following two portions:
• The rst portion is primarily generated from packet headers to identify micro-ows in the trac. The Parameters that are considered
for hash computations by default in RTAG7 hashing is shown in the given example:
Dell#show load-balance
Load-Balancing Configuration For LAG & ECMP:
--------------------------------------------
IPV4 Load Balancing Enabled
Equal Cost Multi-Path (ECMP)
295