CGN port blocks and MAP port sets
Divide one public IPv4 address among subscribers: port blocks per address and per pool (RFC 7768), RFC 7422 deterministic mapping with its forward and reverse lookup, and the MAP-E and MAP-T port set of a PSID (RFC 7597), with the log volume that blocks remove.
RetiPort blocks and port sets
How many blocks fit on one address, how many subscribers a pool holds when each keeps all its blocks on one address (RFC 6888 REQ-2), and how much per-session logging the blocks remove (RFC 7768).
Runs in your browser: integer arithmetic over the inputs, no network and no clock (times are inputs).
Integer arithmetic run in your browser over the port field of a shared IPv4 address. Port blocks: the usable range (1024-65535 unless you change it) is cut into blocks and every subscriber's blocks are counted on one address, as RFC 6888's paired pooling requires; the log figures are RFC 7422's per-session numbers divided by the block size, the factor RFC 7768 gives. Deterministic mapping: RFC 7422 algorithm 0 (Sequential), step by step, forward and reverse, with the configuration record of its section 3. MAP: the port field A | PSID | j of RFC 7597 section 5.1, which MAP-T (RFC 7599) uses unchanged. Times are inputs; nothing reads a clock or the network.
- RFC 7422Deterministic mapping: variables, allocation steps, algorithm 0, the section 2.3 example and the section 3 record (read 2026-10-19)
- RFC 7768Port blocks: one log per block, log generation reduced by the block size (read 2026-10-19)
- RFC 6888Paired pooling (REQ-2), per-subscriber port limits (REQ-4), the 120-second quarantine (REQ-8) (read 2026-10-19)
- RFC 7597The MAP port-mapping algorithm, section 5.1 and Appendices A and B (read 2026-10-19)
- RFC 7599MAP-T uses RFC 7597's port mapping; erratum 5324 corrects its Example 5 PSID to 0x34 (read 2026-10-19)
- RFC 6269Port allocation, traceability and the multiplicative factor (read 2026-10-19)
- RFC 6302Servers log the source port and a UTC timestamp to the second (read 2026-10-19)
- RFC 6335System Ports 0-1023, User Ports 1024-49151, Dynamic Ports 49152-65535 (read 2026-10-19)