we are ISP and we want to start assigning our customer IPv6, as i know assigning /64 for customer is not recommended and minimum recommended network length is /56 and even /48, i need your opinion and what is technical issue we could face if we assign /64
Its all depends on what kind of ISP, is ths IPv6 address using for DSL ? or Hosting ?
RIPE have some good suggestion here : ISP Point of view
RFC for DSL deployment :
Cisco good thread discussion and clarfication for reference :
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Thanks for you reply
in fact the ipv6 will be assigned to business customers means corporate, enterprises and SMEs, who host their services with us, customer could have their own switches, FW, load balancer ,,,etc
Given your customer base a /64 allocation would be considered inadequate. Sure it can hold 18446744073709551616 hosts, but crucially a /64 is the smallest subnet allocation which is considered best practice. In doing so you do no leave your customers any scope for architecting a hierarchical addressing scheme.
You can carve up a /64 into smaller subnets, but have a read of RFC7421 to see why not: