Routing

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  • 1.  Why do we assign a /64 on IPV6 P2p Interfaces

    Posted 10-21-2011 12:59

    Hello Community

     

    I recently started to explore IPV6 and after reading some material i see that authors use a /64 host portion on p2p

     

    interfaces for example in Junos day 1 book i,e, exploring IPV6 author uses the 2001:db8:0:5::/64 on one of the p2p 

     

    interfaces and 2001:db8:0:3::/64 on the other.

     

    My question is isnt it a waste of ip addresses on p2p links in core.As we know that in IPV4 a /30 seems quite logical.

     

    /64 for hosts on a p2p links is way too much when u know that no lan segments are attached and hence SLAAC wont be

     

    utilized

     

    Thanks & Regards

     

    Malik



  • 2.  RE: Why do we assign a /64 on IPV6 P2p Interfaces
    Best Answer

    Posted 10-22-2011 02:41

    Hello there,

    Using /64 gives you 2^(128-64) = 18,446,744,073,709,551,616 IPv6 addresses on a single subnet. That's may seem like a waste, but OTOH, simplifies the ops job greatly since they don't have to learn how to variable-length-subnet hexadecimal IPv6 prefixes 

    Take a look at http://packetlife.net/blog/2010/may/6/ipv6-127-prefixes/  and http://tools.ietf.org/html/rfc3627 section 4 "Solutions".

    HTH

    Rgds

    Alex