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Network and Connectivity Assessment: VPN or Dedicated Links to Cloud
A network and connectivity assessment measures how much traffic will flow between sites, users and cloud after migration, and what latency each application can tolerate, so the right connection is chosen: internet VPN, dedicated links such as Direct Connect, ExpressRoute or Cloud Interconnect, or SD-WAN. NTSPL sizes bandwidth from measured flows and costs each option before waves start.
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What Changes When Applications Leave the Data Centre Switch
On-premises, application traffic stays inside a data centre switch. After migration, the same calls cross a WAN, and a chatty ERP client that worked at 0.5 ms behaves badly at 25 ms. Bandwidth is often sized from a guess, so either a 1 Gbps dedicated link sits at 8 percent utilisation or a 100 Mbps VPN saturates on the first month-end. Data transfer during migration is a separate surprise: 40 TB over a shared link can take weeks.
NTSPL measures flows from discovery data and site routers, probes latency to candidate regions from each site for a full business week, and models post-migration traffic by application. We then compare VPN, dedicated links, partner interconnects and SD-WAN on capacity, resilience, lead time and cost, and calculate migration transfer times per wave so cutover windows are realistic.
Signals That Connectivity Needs Measuring
Signals you need Network & Connectivity Assessment
- More than 5 sites will reach cloud-hosted applications, with mixed MPLS, broadband and 4G links
- Thick-client or chatty applications such as ERP, CAD or PLM are in early waves
- Over 20 TB must be transferred during migration windows
- Dedicated link lead times of 6-12 weeks have not been built into the plan
When to choose something else
- All users are remote, applications are web-based and data volumes are small: provider VPN plus internet is enough without a formal study.
- The links are already live and the question is routing or firewall design: that belongs in the network build.
Network Facts We Measure
Current flows
Site-to-data-centre and server-to-server traffic volumes from router NetFlow and discovery data, by application.
Latency sensitivity
Round-trip time from every major site to candidate regions, matched to each application's tolerance.
Post-migration traffic model
Expected cloud ingress, egress and hybrid traffic after each wave, including backup and replication.
Migration transfer plan
Data volumes per wave converted into transfer time at realistic utilisation.
Link options and cost
VPN, dedicated, partner interconnect and SD-WAN compared on capacity, SLA, lead time and monthly cost.
Flow-to-Link Sizing Model
Flow-Measurement to Link-Sizing Network Model
NetFlow, discovery flows and latency probes produce a measured baseline per site and application. Post-migration traffic is modelled, then link options are sized and costed with resilience requirements.
Select any component
Flow-Measurement to Link-Sizing Network Model: click any of its 7 components to see its role and the design choice NTSPL makes for it, or trace the 7-step primary path.
Hybrid Connectivity Options by Provider
We size Direct Connect at Mumbai-area locations against measured flows and keep Site-to-Site VPN as backup; Transit Gateway concentrates multi-VPC routing.
ExpressRoute circuits in Mumbai or Chennai peering locations are compared with VPN Gateway; Connection Monitor validates latency during the study and after cutover.
Partner Interconnect often suits sub-10 Gbps needs; HA VPN offers a 99.99 percent SLA when configured with redundant tunnels, and Cross-Cloud Interconnect links to another cloud.
Link Selection Rules and Thresholds
VPN or dedicated link
Choose internet VPN when steady traffic is under about 300-500 Mbps, latency variation is tolerable and the budget is tight. Choose a dedicated or partner link when sustained traffic exceeds that, when jitter-sensitive or chatty applications move, or when egress volume makes lower dedicated-link transfer rates worthwhile. Many estates start on VPN and add links by wave.
Resilience per site
Data centres and hubs need two diverse paths, ideally dual dedicated links with different carriers or a dedicated link plus VPN backup. Branches usually need one primary link plus 4G or broadband failover through SD-WAN. Match resilience to the site's tolerance: a plant losing ERP for four hours may stop dispatch.
Latency thresholds
Web applications tolerate 40-60 ms comfortably. Thick-client ERP, CAD file opens and database-chatty applications start degrading above 10-15 ms. Where sites exceed the threshold for a critical application, consider virtual desktops in the same region, a closer region, or keeping that tier on site.
Migration transfer strategy
Calculate transfer time at 60-70 percent of link capacity: 10 TB over 1 Gbps takes about 22 hours at line rate and over 30 hours realistically. For large datasets, pre-seed by replication weeks ahead and transfer only deltas in the cutover window, or order temporary extra bandwidth.
Four-Week Network Assessment
Flow collection setup
NetFlow export enabled, temporary collectors placed and probes installed at major sites.
Measurement period
Two weeks of flows and one full business week of latency data.
Traffic and transfer modelling
Post-migration traffic per site and transfer times per wave calculated.
Options and plan
Link options costed, resilience chosen and order dates aligned to waves.
What you receive
Network Readiness Measures
| KPI | Typical target |
|---|---|
| Sites with measured latency to target region | 100 percent of sites over 20 users |
| Peak link utilisation after migration | Under 70 percent |
| Cutover windows met for data transfer | 100 percent |
| Application latency complaints after migration | Zero for sites within threshold |
Connectivity Assumptions That Fail
| Risk | How NTSPL prevents it |
|---|---|
| Dedicated link ordered too late | Order dates are calculated back from wave dates using carrier lead times of 6-12 weeks. |
| IP overlap between sites and cloud ranges | Address plan checked against all sites and existing cloud networks before design. |
| Egress cost underestimated | Modelled egress per option, including backup and reporting extracts. |
Do we need Direct Connect, ExpressRoute or Interconnect, or is a VPN enough?
A VPN is enough when sustained traffic is a few hundred Mbps, applications are web-based and some latency variation is acceptable; it is quick to set up and cheap. A dedicated or partner link is worth it when sustained traffic is higher, chatty or real-time applications move, egress volumes are large, or the business needs predictable latency and an SLA-backed path. In Indian mid-market estates we often see VPN for early waves and dedicated links ordered for the ERP or plant wave. Measured traffic, not vendor preference, should decide, and the dedicated link's 6-12 week lead time must be planned.
Key facts: Network & Connectivity Assessment
Network & Connectivity Assessment in Practice
2 Network & Connectivity Assessment scenarios, from Cement manufacturing and Tyre distribution (dealer network), plus related platform case studies.
Cement maker links 5 plants to Azure and AWS through one partner exchange
Tyre distributor proves 1,400 dealers can use a cloud portal on 4G and broadband
Specialty chemicals group links 6 plants and HQ to AWS with dual-path hybrid network
Container terminal links TOS, gate automation and Azure over dual ExpressRoute
Network & Connectivity Assessment: Frequently Asked Questions
How long does a network and connectivity assessment take?
Four weeks for most organisations: one week to set up flow export and probes, two weeks of measurement, and a week for modelling and costing. Sites without flow export may need temporary collectors, which we ship pre-configured. Results also feed the placement and readiness assessments.
What does a network and connectivity assessment cost before migration?
Typically 10-16 consultant days plus any temporary collector hardware. Site count drives the effort more than bandwidth, so organisations with many branches sit toward the upper end. Carrier quotes are gathered for shortlisted options so costs reflect current Indian pricing.
Which Indian locations offer dedicated cloud connections?
All three providers offer dedicated or partner connectivity at locations in major Indian metros, with Mumbai and Chennai most common. We confirm current locations and partner carriers per provider before recommending a link. Partner interconnects through Indian carriers suit sites far from those metros.
Can branches connect directly to cloud instead of through the data centre?
Yes, often through SD-WAN with direct cloud on-ramps, which removes hairpinning through the data centre. We test whether security inspection requirements allow it before recommending it. SD-WAN cloud on-ramps also make adding a second cloud simpler later.
How do you estimate migration data transfer time?
We use 60-70 percent of link capacity, not line rate. At that utilisation, 10 TB over 1 Gbps takes over 30 hours, so large datasets are pre-seeded by replication with only deltas moved at cutover. Delta transfer windows are rehearsed before the cutover weekend.
Should dedicated links be encrypted?
Dedicated links are private but not encrypted by default. Regulated entities often require encryption, using IPsec over the link or provider MACsec options where available. We confirm the requirement with security first. Any encryption overhead is included in bandwidth sizing.