Catalogs, accounts, and billing cycles moved onto Cerillion while the source stack stayed live. Parallel runs, then a rehearsed cutover. The first cycle on Cerillion was not the first time those invoices had been produced.

Cerillion BSS migration

Comverse One and online charging cut over without dropping recharges. Rating, balances, and voucher flows were rehearsed against live-shaped traffic before the first prepaid event on the new path.

Comverse One charging cutover

BSS jobs moved onto Kubernetes. Zabbix watched cluster, node, GPU, and job health. Alerts became tickets in the NOC, not graphs someone happened to have open.

Kubernetes and Zabbix for BSS operations

A local model over runbooks and historic tickets. Agents get cited answers on the floor. Subscriber and billing data do not leave the operator network.

Runbooks on-net for billing operations

Self-care and internal consoles rebuilt around the jobs that close a ticket: top-up, catalog lookup, payment status. The screens sit on the live stack.

Care and ops screens people open

SMS charged through Comverse OCS over Diameter. Premium and bulk events had to rate the same after the SMSC change, without a silent drop of MO/MT charging.

Mavenir SMSC to Comverse OCS

Legacy Nokia core nodes replaced with Ericsson while VoLTE and 4G stayed up. Provisioning and charging kept a single subscriber truth through the move.

Nokia core to Ericsson core

Online charging extended for 5G NSA then SA. Rating and policy had to survive new session types without rewriting every prepaid offer.

OCS for 5G NSA and SA

OCS, billing, and ERP stopped being three versions of the customer balance. Night jobs produce a difference file with owners, not a spreadsheet in someone's inbox.

Billing and ERP reconciliation

Offers, bundles, and dependencies moved into a catalog Cerillion could bill. Commercial still changed prices. Engineering stopped discovering the offer in production.

Catalog and offer migration onto Cerillion

Care, contracts, and the billing account on one customer. Agents stopped asking the subscriber to repeat an account number that billing already had.

Unified CRM for care and contracts

Orders that failed in provisioning stopped sitting in a report. Fallout is a queue with a reason code and an owner, including the night the activation spike hits.

Order fallout that becomes work

An MVNO's prepaid offers rated in real time on the host charging path. Recharges from the MVNO's channels hit the same balance the network used.

Real-time prepaid charging

Interconnect and partner traffic rated and settled in the currencies and tax rules the contract actually used. Disputes start from a usage file both sides can open.

Wholesale partner settlement

Card and wallet payments from the bill run retry on a rule, then settle back to the account. Failures are a reason code, not a silent skip.

Payment gateway with retries that settle

Wallet top-ups credit the same prepaid balance used on-net and in roaming. FX is on the credit, not a surprise on the next recharge.

Wallet top-up and roaming balances

Physical SIM and eSIM activate from the same order. Inventory, HLR/HSS, and billing see the IMSI when the customer does, not the next morning.

SIM and eSIM provisioning

Numbers, ports, and addresses moved to a new inventory while orders kept completing. Dual-write, then cut the old store when the counts matched.

Inventory migration without a freeze

Catalog, CRM, and orders talk over TM Forum APIs instead of nightly files. Product and party are the same objects the bill already used.

TM Forum APIs between catalog, CRM, and orders

Promon took the night queue for BSS jobs and Sev-1s. The operator's day team still owns commercial change. The bill run has a named shift.

24/7 ops through the bill run

Releases to billing-adjacent services went through pipelines with a gate the bill-run calendar owns. Friday deploys that hit a cycle were blocked by policy, not by a chat message.

Pipelines on a live BSS

An MVNO launched on a host stack: offers, care, self-care, and porting. The host still ran charging. The MVNO still owned the brand and the complaint.

MVNO launch on host BSS

Usage-rated invoices for a utility. Same discipline as a telco bill run: a calendar, a rehearsal, a rollback, ERP on the same numbers.

Invoice cycle for a usage-billed utility

Settlement and retry jobs watched through the night. Failures become tickets before the next clearing window, not after merchants call.

Night operations for a payments processor

Accounts, usage history, and open balances moved with a reconciliation the target BSS could defend. History was not 'best effort'.

Care and ops screens people open

The constraint

What we did

How it ran

What was true after

Stack in the room

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