Use case 03 of 03 plan reversible

One control plane
instead of five.

The transition case is simplification, not renumbering. Fewer moving parts in the core, no per-tunnel state to scale — and per-flow behaviours a full mesh cannot express at all.

51

control planes in the core SRv6 removes LDP, RSVP-TE and BGP-LU; the IGP carries the uSID block as an ordinary prefix

39,8000

tunnels of state in the core A full mesh of 200 PEs is N(N−1) unidirectional LSPs — arithmetic, not a vendor claim. SRv6 holds the path at the ingress edge only

0 bytes

added header, up to six segments An SRH carrying the same six segments adds 104 bytes (8 + 6×16). Six 16-bit instructions after a 32-bit block is exactly 128 bits — the destination address itself · RFC 8754 · RFC 8986

What we move: the core stops carrying per-flow state it never needed. No MTU erosion, no hardware header-parsing requirement, and a plan that strands nothing on the way there.

0100 why it collapses

The destination stopped being a place. It became a program.

Six hops fit in the destination address itself. Each node matching the leading instruction shifts the address left and forwards on what is now in front of it — no added header, no per-flow state anywhere in the middle.

The honest description is that the destination has become a program counter. That is why five control planes collapse into one: the path is held at the ingress edge, and the core just forwards.

one address · four instructions · rewritten at every hop

0200 getting there

Reversible, and it strands nothing.

Plan against the live RIB

The addressing plan is proposed against the routing table you actually have, and checked for reachability before anything is written. The check is a proof, not an opinion.

One write path

Every change to the network goes through the same proposal, verification and approval sequence. The gate is mechanical, not procedural.

Reversible at every step

Each step is independently useful and independently undoable. Stop after the audit and you still keep the output.

The transition case is simplification, not renumbering.

e000 End.DT6 deliver

See the plan against your own core.

The entry is still the read-only audit on what runs today. 30–60 minutes, no change window, and the arithmetic is computed on your estate rather than ours.

Book 30 minutes — read-only