> As there is AFI=16387 Type 5, I would like to suggest an additional Type by
> which the geographical coordinates wrt longitude and latitude are bijectively
> mapped to {square degree#,square minute#, second row#, second column#} such
> that the meridian (east/west) and equator ( north/south) dominated scheme is
> transformed into a fast addressable (offsetting) scheme which starts at the
> south pole and which only knows the directions to-east and to north as by the
> following:
Why? Can you give us a specific use-case.
> (1) Unicast:
> Square degree#:
> The globe may be conceived as 180 rings of spherical triangles/rectangles,
> starting at the South pole with a ring of 360 spherical triangles, each of
> which is limited by two longitudes and latitude 89° South from the Equator.
> Towards North there follow 178 rings of 360 spherical rectangles, each of
> which is limited by two consecutive longitudes and latitudes. Finally there
> is a last ring of 360 spherical triangles around the North pole.
> Each spherical triangles/rectangles is assigned a square degree number from 1
> to 64800, starting at the South Pole with that triangle which is limited by
> the two longitude degrees 0 and 1 East, the South Pole and latitude 89 South,
> winding from there in eastbound direction, while forming a full circle such
> that number 360 is assigned to that triangle, which is limited by the two
> longitude degrees 1 West and 0,while number 361 is assigned to that spherical
> rectangle, which is limited by the longitude degrees 0 and 1 East and the
> latitudes 89 South and 88 South. While winding in eastbound direction and
> while winding towards the North Pole, the last number 64800 is assigned to
> that spherical triangle which is limited by the longitudes 1 West and 0, the
> latitude 89 North and the North Pole.
>
> Square minute# derived from given longitude minute x and latitude minute y.
> if South of the Equator then minute row# = 60 –y else minute row# = y+1
> if West of Greenwich then minute column# = 60- x else minute column# = x+1.
> square minute# = (minute row# -1) times 60 + minute column#Square minute#
> derived from given longitude minute x and latitude minute y.
>
> second row# and second column# derived from given longitude second x and
> latitude second y.
> if South of the Equator then second row# = 60 –y else second row# = y+1
> if West of Greenwich then second column# = 60- x else second column# = x+1.
> (no second square# needs to be calculated)
>
> The proposed enhancement would enable a next-hop determination by either one
> or three table offsets in case of unicast forwarding
>
> (2) Multicast
> Multicast-Locator {square degree#; "multicast address"-number which is
> unique per indicated square degree}
> Well-known Multicast-Locator {square degree# =64801; standardized "Multicast
> address" number for that well-known service}
>
> The Multicast-Locator enables the retrieving of the proper entry from a new
> Multicast-FIB entry (inside a participating node only) which enables multiple
> concurrent next-hops eventually.
But a multicast entry will describe a set of receivers spread across the
planet. So the concept of a multicast group have a physical presents is in
conflict to its traditional and fundamental meaning.
> (3) Anycast
> Anycast-Locator {square degree#; "anycast address"-number which is unique
> per indicated square degree}
> Well-known Anycast-Locator {square degree# =64802; standardized "Anycast
> address" number for that well-known service}
>
> The Anycast-Locator enables the retrieving of an entry of a new Anycast-FIB
> (inside a participating node only) which enables just one next hop.
>
> While (2) and (3) specify which one out of multipe
> Multicast/Anycast-services, at a more general place of the LISP header there
> should be
> some flags which indicate the fundamental forwarding type
> 0=unicast,1=multicast, 2= anycast, 3=.broadcast, 4=mp2p,.....)
This is going to be a problem as well. An anycast address is multiple unicast
address residing in physically different places. One would have a semantic
issue knowing if an address is in multiple physical places (same as the
multicast point I brought up above) or an address has moved from one physical
location to another.
Dino
>
> H.H.
>
>
>
>
>
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