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Re: [RRG] new draft on " A Taxonomy for New Routing and Addressing Architectu...
Heiner,
sorry for this belated reply.
On Apr 1, 2008, at 7:47 AM, HeinerHummel@aol.com wrote:
What is a topologically aggregatable address ? Or better asked, is
the TAA a topologically aggregatable address?
yes
TAA = Topologically Aggregatable Address
E.164 telephone numbers are topologically aggregatable addresses.
Indeed, in former days the mapping was done mechanically. Each digit
selected the next link mechanically, even before the over-next digit
was dialed. In West-Germany leading digit "3" was reserved for the
eastern part for 45 years anticipating the reunion. So there is a
real relationship between number and route/location.
I have my doubts wrt. TAA. Aren't TAAs just aggregatable addresses,
ie. AAs? I thought IP addresses do not contain any topology
information, no matter whether they are aggregatable or not.
Quote from the draft: This terminology is chosen to avoid confusion.
Heiner
thanks for the feedback. We are in the process of refining the
terminology. It is really important to get this right, to be able to
carry out meaningful design discussions.
It looks to me the above confusion seems coming from not defining
"topology" first.
What we mean by topology is Internet topology (not geographic
topology), i.e. the ISP AS interconnectivity.
TAAs are addresses that can be aggregated on a per ISP AS basis, i.e.
it would be possible to aggregate all the prefixes belonging to one
ISP AS to one routing entry, without losing reachability.
- so TAAs are never assigned to edge users.
- This definition by no means implies that the TAA would contain
no bits that hint geo location of a prefix; rather it only requires
that the *highest order bits* identify ISP ASes.
Of course each AS is not necessarily limited to announce only one
prefix; the normal policy/TE practices can perform, within the
constraint of routing scaling.
Lixia
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