32-Bit AS-Numbers in German HAMNET

IP-Koordination Germany assigns as-numbers and ip-networks under the following policies:

  • :!: POLICY: Every autonomous system (AS) must include several locations (Sites)1).
  • :!: POLICY: Every autonomous system (parent-AS) has been assigned a 16-bit-AS-number.
  • :!: POLICY: Every parent-AS has been assigned a block of 100 32-bit as-numbers derived from the last 3 digits of the 16-bit as-number.
  • :!: POLICY: Every parent-AS has been assigned different ip-subnetworks for backbone and user/services.
  • :!: POLICY: Every site within the parent-AS gets a 32-bit as-number out of the parent-AS pool.
  • :!: POLICY: There has to be „site-to-site eBGP routing“ within the parent-AS.

According to the X.121 Dokument of ITU, Germany has got the four county-codes 262 to 265. According to the proposal for assigning private 32-bit-as-numbers in AMPRNettm, Germany has four blocks of as-number-range, with 100000 32-bit-as-numbers each(status: 01.01.2020).

AS-block Usage
42263XXXyy future use
42264XXXyy future use
42265XXXyy future use

This is a huge amount of numbers! At the moment in German HAMNET only the first 32-bit-as-block has been used. IP-Coordination Germany assigns 32-bit-numbers in blocks with 100 each (see digits yy=0-99) to the existing parent-AS. Assignment of digits XXX follows a principle called „as-based numbers“.

In this variant the last 3 digits of the 16-bit parent-as-number are placed into the first of the five available digits of the new 32-bit as-block. The last 2 digits of the new 32-bit as-number are freely available for usage at sites within the parent-as. The as-maintainers are free to decide how the 32-bit-numbers are used at the local sites within their parent-as.

Example AS64625

AS64625    the last 3 digits are 625
possible 32-bit-AS-range within AS64625:
42 262 625 yy --> from 4226262500 to 4226262599 


  • no central registry neded for 32-bit as-numbers
  • maintainer of parent-as can use them immediately
  • no doubles possible in other parent-as
  • affiliation to the right 16-bit parent-as is human readable
  • no effort in administration when ip-networks are transferred
  • AS-numbers remain at their location when ip-networks must be transferred
  • mapable to the structure of HamnetDB without any problems


  • „only“ 100 32-bit-as-numbers available for each 16-bit parent-as
  • ???

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a single site is no as!
  • en/hamnet/as-nummern/32-bit/policy-dl.txt
  • Zuletzt geändert: 09.12.2020 21:11 Uhr
  • von dd9qp