Users Guide

The longest prefix match (LPM) table on the system supports different types of prefixes for IPv6 and IPv4. The
route table, also called the LPM table, is divided into the following three logical tables:
1 IPv4 32-bit LPM table (Holds IPv4 Prefixes)
2 IPv6 64-bit LPM table (Holds IPv6 Prefixes less than /65 Prefix Length)
3 IPv6 128-bit LPM table (Holds IPv6 Prefixes greater than /64 Prefix Length)
The LPM table, which is 8K in size, is a dedicated table. It comprises eight ternary content addressable
memory (CAM) blocks, with each block being 1K in size. The table can contain 16KIPv4 route entries or 8K
IPv6 route entries (less than /65 prefix-length) or 3K IPv6 route entries (greater than /64 prefix-length). You
can configure the LPM table with one of the following partitions to support the IPv4 and IPv6 prefix route
entries:
• Partition 1: IPv6 128-bit LPM entries can be stored in this partition. IPv4 and 64-bit IPv6 entries cannot
be saved in this partition.
• Partition 2: IPv4 LPM and 64-bit IPv6 LPM entries can be stored in this partition.
The platforms uses only IPv6 /0 – 0/64 prefix route entries. Support for /0 – /128 IPv6 prefix route entries is
available, although they are not utilized. A total of eight pools or regions are present with each region
containing 1024 210-bit entries (supports up to 0/64 prefix). To support up to /128 prefixes, you must use 2
banks (410-bit entries). It is necessary to partition the LPM.
The optimized booting functionality does not use Openflow and therefore SDN support is not available. LPM
partitioning might have a slight impact on the number of SDN-programmed L3 entries because the LPM
space becomes reduced.
IPv6 Header Fields
The 40 bytes of the IPv6 header are ordered, as shown in the following illustration.
Figure 50. IPv6 Header Fields
IPv6 Routing 478