Episode 18 — Document Interconnections and Dependencies
In Episode Eighteen, titled “Document Interconnections and Dependencies,” we begin by tracing every relationship your service maintains with systems beyond its authorization boundary. The Federal Risk and Authorization Management Program—FED RAMP after first use—lives and dies on clarity, and nowhere is clarity more fragile than at the edges where data crosses into someone else’s environment. A clean picture of those edges turns surprises into planned events and makes assessment feel like confirmation. Think in paths, not wishes: who calls whom, what goes over the wire, where trust is established, and how breakage is noticed. If you can narrate each connection without pausing to “check with the team,” you are close. If the story depends on tribal knowledge, your interconnections are risks wearing the mask of convenience. We will replace that mask with documentation others can read and test.
Define interconnection plainly so every stakeholder hears the same thing: an interconnection is an authorized, intentional exchange of data or control messages between two distinct systems with different owners or authorizing officials. It is not “some traffic allowed by a firewall.” It is a deliberate relationship, justified by mission, bounded by scope, and governed by written expectations on both sides. In federal contexts, this often takes the form of an Interconnection Security Agreement—I S A after first use—or a Memorandum of Understanding—M O U after first use—paired with technical details in your System Security Plan. The definition matters because it draws a bright line between what your boundary secures directly and what you rely on others to secure. When the line is bright, responsibilities are easier to assign, prove, and review.
Start a working catalog of dependencies that orients readers quickly. Upstream providers deliver capabilities you inherit or consume: infrastructure platforms, managed identity services, content delivery networks, external logging and analytics, or government-operated gateways. Downstream consumers receive your data or events: agency systems that ingest exports, partner tools that poll your APIs, or reporting surfaces that mirror your content. Shared services sit beside you with mutual reliance: ticketing, paging, incident collaboration, and joint monitoring hubs. The catalog is not a shopping list; it is a map that answers three questions for each entry: who owns it, what function it serves in your architecture, and how its health or failure affects your mission. Without this map, every outage looks like an ambush and every assessment question spawns a scavenger hunt.
For each connection in that catalog, record purpose, data types, and business justification in full sentences. Purpose states the mission result the connection enables—such as “deliver status updates to the sponsor’s case system” or “retrieve identity assertions from the government directory.” Data types name the fields actually exchanged—contact details, ticket identifiers, error metrics, or hashed tokens—and whether payloads ever include sensitive content by design or by mistake. Business justification ties the connection to an objective a reviewer understands, so the risk trade can be judged: reduce duplication, meet a reporting mandate, or provide real-time triage. This tight trio—purpose, data, justification—keeps the discussion grounded. When someone asks why a connection exists, you can answer without handwaving, and when someone proposes a new one, you can evaluate it with the same lens.
Specification transforms intent into a testable interface. Write down endpoints, authentication methods, protocols, and encryption-in-transit with the same names your tools use. Endpoints include URLs, IP ranges, queues, and topics. Authentication should name the mechanism—mutual T L S, signed tokens, S A M L assertions, Open I D Connect—plus certificate authorities or trusted issuers. Protocols should include versions and ciphers where applicable, not just “HTTPS.” Encryption-in-transit should state whether termination occurs at a gateway or a service, how keys are managed, and what rejects a downgrade. The point is not verbosity; it is reproducibility. An assessor should be able to follow your paragraph, initiate a controlled request in a test window, and see the same handshake, the same headers, and the same protections you claim.
Note partner authorization status and monitoring obligations clearly, because assurance is shared only when it is visible. If the partner system carries an Authorization to Operate—A T O after first use—capture the scope, the owner, and the effective dates that overlap your reliance. If the partner is a commercial platform, collect equivalent attestations and security summaries. Then state monitoring expectations in words that survive turnover: what logs you receive, what dashboards the agency watches, how often summaries are delivered, and what triggers joint triage. If your design assumes the partner will alert you to anomalies, write that assumption here and name the channel. Without explicit status and monitoring lines, you are trusting a silhouette, not a system.
Beware of the “temporary” connection that becomes a permanent risk. A backdoor built for a one-time data load, a jump host prepped for a vendor debug session, or an ad hoc export path created to meet an urgent report often outlives its reason. Months later, the artifact still exists, still passes traffic, and still sits outside your normal monitoring and review. The remedy is a two-part discipline. First, time-box temporary connections with automatic expiration and visible tracking in tickets and inventories. Second, convert anything that proves useful into a formal interconnection with the same purpose, protection, and proof demanded of every other path. If you cannot bring it into the light, retire it. “We’ll remove it later” is not a control; it is a promise that becomes a finding.
Standardization is a low-effort win that pays every time a new request appears. Create a simple connection request template that forces the right fields: requester, purpose, data types, endpoints, auth method, expected volume, sponsoring owner, and proposed review cadence. Pair it with review checkpoints in your change process: design review to assess risk, pre-production validation to confirm protections, and post-deployment verification to ensure monitoring works. Keep the template short enough that engineers actually use it and strict enough that risk owners can say “yes” or “no” without reading tea leaves. A template spares you the false choice between speed and safety; it gives you both by making the path predictable.
Responsibility lines must be explicit for incident reporting, contact points, and change notifications. Name who detects, who declares, who notifies whom, and within what time windows. Provide 24x7 contact routes with rotations and an escalation ladder that crosses organizational boundaries. For changes that affect the connection—certificate renewals, endpoint moves, schema shifts—state the notification lead time you require and the approval path you honor. If the partner’s policy differs, reconcile it now and record the compromise. When an incident occurs, ambiguity is the enemy. Your paragraph should read like a runbook: if this class of event touches this interface, these people gather in this channel within this many minutes, and this evidence is shared on arrival.
Imagine a practical scenario: the partner rotates certificates on a mutual T L S interface. You coordinate the update without downtime because the interconnection record already states renewal cadence, supported cipher suites, and the cutover procedure. Your team imports the partner’s new certificate into a staging trust store, validates handshake in a non-production environment, and then adds it to production trust side by side with the old one. After verification, the partner flips their endpoint to present only the new certificate, your monitors confirm uninterrupted success rates, and you remove the old trust entry before its expiration date. A post-change note lands in the interconnection log with timestamps, fingerprints, and links to monitoring evidence. No scrambling, no guesswork—just execution guided by documentation you can show.
Use a compact anchor phrase to keep your paragraphs sharp: purpose, protection, proof, people. Purpose reminds you to state why the connection exists in mission terms. Protection reminds you to describe authentication, protocol, and encryption details that actually block bad days. Proof reminds you to name the logs, dashboards, and reports that demonstrate the connection behaves as described. People reminds you to list owners, responders, and approvers with contact paths and timelines. Say the four words before you approve a new connection or review an old one. If any word lacks content, the record is not ready for assessment or for production reality.
Ensure your agreements cover termination, fallback plans, and data handling from first byte to last. Termination clauses should define how either party disconnects safely, how keys and trust entries are removed, and how residual data is purged or archived according to policy. Fallback plans should spell out degraded modes—queued messages, cached results, or read-only operation—so missions do not fail when a partner has a bad day. Data handling should state retention periods, masking or minimization on the wire, and conditions that prevent sensitive content from leaking into logs or analytics. These terms are dull until the hour you need them; then they are the only sentences that matter.
Review your interconnection list quarterly and retire what no longer earns its keep. Quarterly is frequent enough to catch drift and light enough to finish. For each entry, confirm that purpose still holds, data types have not crept, endpoints and auth match reality, authorization status remains current, and monitoring shows life. If a connection is idle, decommission it with the same care you used to create it and record the change. If a connection has multiplied—multiple partners hitting the same interface—consider standardizing through a gateway pattern to reassert control. The signal of health here is churn: some connections join, some leave, none linger without a champion.
We wrap by closing the loop between documentation and action. Interconnections become real when they are described in language a reviewer can test and an operator can follow under pressure. You have a definition that sets scope, a catalog that orients, specifications that reproduce, statuses and obligations that keep trust visible, and agreements that make endings as deliberate as beginnings. Your next action is simple and high impact: request written confirmations from each partner on the record—current endpoints, auth details, renewal cadences, incident contacts, and authorization status—and attach the replies to your interconnection entries. When partners echo your documentation back to you, edges stop being mysteries and start being assets you can manage with confidence.
