# What is route failover in messaging?

> Route failover is the automatic re-routing of an SMS submission from a failing primary route to a healthy secondary route, ideally within the same submit_sm transaction. For a CPaaS handling tens of millions of messages a day, failover is the difference between a 99.9% delivery rate and a 99.05% rate — a tenfold difference in user-visible failures.

- Canonical URL: https://www.broadnet.me/answers/what-is-route-failover
- Language: en
- Last reviewed: 2026-07-22
- Publisher: BroadNet (https://www.broadnet.me)

## What triggers a failover

Three classes of trigger. Hard failures: TCP disconnect to the destination SMSC, SMPP bind expiration, persistent submit_sm error codes (ESME_RSYSERR, ESME_RTHROTTLED). Soft failures: latency p95 exceeding a threshold, DLR success rate dropping below a per-route minimum (e.g. <85%), per-operator congestion windows tightening. Predictive triggers: scheduled maintenance windows on partner routes, known operator-side incidents from upstream signal.

## How fast it has to be

For an OTP, sub-second failover. For a marketing campaign, can be 5-30 seconds. BroadNet's routing engine evaluates per-message in under 5ms, applying the cheapest-delivering rule with per-operator quality scores updated in real time. If the primary route is degraded, the secondary is selected before the message ever hits the wire.

## The traps

Naive failover routes to the same operator's SMSC via a different aggregator — which is meaningless if the issue is operator-side. Good failover routes to a structurally different path (different SS7 PoP, different transit aggregator, different MNC if the destination supports it). The best failover knows the failure mode and picks accordingly: a TCP-level failure means try the same operator via a different transit; an HLR-level failure means try a different operator-portability path.

## What buyers should ask

Ask your aggregator: "Show me your route map and your route-quality scoreboard for the last 30 days, per destination operator." An aggregator that can't show this doesn't have real failover — they have a single route and they pray. BroadNet's customer-facing route dashboard updates every minute. Available to every account, not just enterprise.

## Related

- [All answers](https://www.broadnet.me/answers)
- [Glossary](https://www.broadnet.me/answers)
- [What is hop-by-hop latency in SMS delivery?](https://www.broadnet.me/answers/what-is-hop-by-hop-latency)
- [What is a DLR (Delivery Receipt)?](https://www.broadnet.me/answers/what-is-dlr)
- [What is a throughput SLA?](https://www.broadnet.me/answers/what-is-throughput-sla)
- [SMS API](https://www.broadnet.me/products/sms-api)
- [Omnichannel](https://www.broadnet.me/products/omnichannel)