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Limited number of IPv6 NDP entries
When I configure SDM to use dual-stack (IPv4 and IPv6), I do expect to use both. However, at least with firmware 11.0.0.31, I get this limits: (switchcore) #show sdm prefer The current template is the 'dual ipv4 and ipv6 data center with IP Multicast Support' template. ARP Entries.................................... 4096 IPv4 Unicast Routes............................ 6112 IPv6 NDP Entries............................... 1024 IPv6 Unicast Routes............................ 3072 ECMP Next Hops................................. 16 IPv4 Multicast Routes.......................... 512 IPv6 Multicast Routes.......................... 256 Maximum VLAN Entries........................... 1024 What is strange is the low limit of IPv6 NDP Entries. For IPv4 hosts, each machine uses one ARP entry. However, for IPv6, you normally use two (link-local and global), but you can use more than that if you are using privacy extension (enable by default on most OS). So, in practice, switch can deal with 4k IPv4 hosts but normally less than 340 IPv6 hosts (1024/3). It can handle about 6k or IPv6 unicast routes, which is far more than hosts. Am I reading this wrongly or something is not well balanced? What will happen when "IPv6 NDP Entries" is exausted? Switch datasheet says that it has "6K ARP/NDP". I'm guessing it is 6k "shared" between both. However, 4096+1024 is 5K, not 6K. Where did that 1K go? I really need it back.