Re: [nesg] RE: status update for ESnet

Michel:

The simple answer is that 128-bit prefixes are required for the loopback
address in a Juniper router.  Host address are required for the loopback
for both IPv4 and IPv6.

Regards,
Mike Collins
LBNL/ESnet
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Bob,

> Interfaces addresses are globally unique and are /64s.
> Loop back addresses are globally unique /128s from a common /64.

I am curious about the /128 loopbacks. I typically don't treat loopbacks
differently than any other interface on a regular subnet, meaning I give
them a /64 as well.

I understand that, contrarily to /127 commonly used on ptp links, /128
addresses do not violate [addrarch], so doing this is ok.

However, the use of /128s out of a "loopback pool" /64 makes loopbacks
unaggregatable, where using /64s could make them aggregatable.

I am curious about the reasons behind the choice of /128s for loopbacks.
Is there a deliberate choice to make them unaggregatable (which has
operational advantages as well as drawbacks)?

Thanks
Michel.