Connect. Secure. Manage.
Dual Internet Connection Design
Design dual internet connectivity for Cisco or Meraki sites, considering carrier diversity, routing choices and real application failover requirements.
Devices supported
across the UK
Client locations
supported
Traffic handled
at peak time
Average
response time
Average response is not a resolution time or a contractual guarantee. Support scope and response commitments are agreed for each engagement.
Dual internet connection design gives a business an alternative path when its preferred connection fails, but the outcome depends on more than installing a second line. Addressing, physical diversity, routing and application behaviour determine whether the backup is useful. MCI Network Services designs Cisco and Meraki connectivity around the failures the customer needs to withstand and the service that can realistically be delivered while one connection is unavailable.
The whole path
Understand how sites, providers, cloud networks and security controls fit together.
Resilience that can be tested
Separate a second circuit from genuine end-to-end service resilience.
Provider coordination
Keep addressing, routing and escalation ownership clear across organisations.
Define the purpose of the second connection
The second service may provide standby access, share normal traffic or support a particular application. We establish which objective applies and how it should affect routing and security policy. A design intended only for emergency browsing should not be presented as equivalent to continuous operation of inbound applications and site-to-site services.
We identify the important workflows and their tolerance for interruption. Voice, remote access, cloud sessions and externally allowlisted connections can react differently when the path changes. The requirement should describe the business outcome rather than rely on the assumption that every application automatically follows a new default route without consequence.
Standards & partnerships
Confidence in the team behind your network.
Cisco Partner
Cisco Meraki
Cyber Essentials
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Check genuine provider and physical diversity
Different supplier names do not necessarily mean independent infrastructure. We review the available evidence about local access routes, building entry, provider equipment and upstream dependencies. Where diversity cannot be confirmed, the design records the uncertainty instead of claiming that the second service protects against a shared cable or carrier failure.
The local environment matters too. Both circuits may terminate on one powered device or depend on the same switch and electrical feed. We examine those shared components and decide whether the availability requirement justifies changes beyond the internet services themselves.
A useful starting point
Not sure where to start?
Bring the requirement. We will help you define the engineering work.
Choose the routing and addressing approach
The appropriate method depends on the public addressing and services in use. Some businesses can use supported static or tracked routing, while others need a more involved multi-provider arrangement. We do not assume BGP is required simply because two circuits exist, or that provider-assigned addresses can be used unchanged through another network.
Outbound translation, inbound applications and VPN endpoints are reviewed together. A different public source address can affect external security rules, and a published service may need DNS or other recovery mechanisms. Those dependencies are included in the plan before failover is described as complete.
Different environments. The same care.
Built around the work
your network supports.
Finance, banking and the wider private sector. We start with the systems and people that depend on your connections.
Finance & banking
Market-data paths, routing and provider coordination on clients’ behalf.
Financial-market services ↗Offices & multi-site teams
Reliable access between people, workplaces and business applications.
Office network design ↗Data centres & cloud
Network boundaries, workload connections and operational ownership.
Data centre networks ↗Design health checks around usable service
A physical interface remaining up does not prove that the provider can reach the destinations the business needs. We assess the supported detection mechanisms and the conditions that should trigger use of the alternative path. The chosen signal should reflect meaningful service availability without causing repeated changes because of one unreliable test destination.
Recovery thresholds and restoration behaviour are also considered. A preferred connection returning briefly after a fault can create another interruption if traffic moves back too quickly. We test the supported behaviour and agree the appropriate operational response instead of treating the default settings as universally suitable.
Plan capacity and security during failover
The backup may have less bandwidth, different latency or usage constraints. We identify which applications remain essential and how traffic should be treated when the preferred path is lost. A reduced-service plan can be more useful than an unrealistic promise that every workload will operate normally through a much smaller circuit.
The alternate path must retain the required security controls. Directly connecting a backup modem around the normal firewall may restore access while bypassing protection. We review the full traffic path and ensure the customer understands any deliberate difference in inspection or policy during an outage.
Test application behaviour from real endpoints
Acceptance includes representative user and server workflows before and after a controlled failure. We observe source-address changes, VPN recovery, DNS behaviour and the treatment of established sessions. A device's failover status is not sufficient evidence that an external application accepted the new connection.
Restoration is tested separately, with clear stop conditions and a route back if a critical service is affected. The record states which faults were exercised and which remain design assumptions. This gives the operations team a realistic view of what the dual-connection arrangement can deliver.
Make the backup an actively maintained service
A standby circuit needs monitoring and periodic checks even when it carries little normal traffic. Provider changes, expired subscriptions or altered upstream equipment can leave it unavailable when needed. We assign responsibility for those checks and keep contact and configuration records current.
MCI can assess an existing pair of connections or prepare a new design within a wider internet edge network. Share your circuits, public services and continuity priorities. We can identify the addressing, routing and operational work needed to make the second connection a useful recovery path rather than an untested extra expense.
Technical references
- MX load balancing and flow preferences — Cisco / Cisco Meraki
- Site-to-site VPN failover behaviour — Cisco / Cisco Meraki
Talk to a specialist
What does your network need next?
Tell us what you are planning, changing or trying to improve. We will help define a practical next step and the engineering scope.
+44 203 196 6566Choose option 1
sales@proxar.co.ukUK-wide service.
Most of our engineers are based in Kent, with a focus on London, Sussex, Essex and Berkshire.
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