What is IP Transit?
IP Transit is the internet egress service that enterprises purchase from upstream network providers. Put simply, when your organization needs to connect to the global internet, you need an "exit" — that exit is IP Transit. The provider announces the global routing table to your network via BGP (Border Gateway Protocol), enabling your data to reach any destination on the internet.
Unlike general broadband access, IP Transit typically serves enterprises or service providers with their own AS numbers (ASNs), offering controllable routing policies, SLA guarantees, and larger bandwidth capacity. For businesses operating across multiple regions, choosing the right IP Transit solution directly impacts user experience, business reliability, and cost control.
BGP Session Types: Full Table vs Default Route
When configuring IP Transit services, enterprises need to understand two core BGP session types:
Full Table: The upstream provider sends all known internet route entries to your router (currently around 1 million IPv4 routes). This means your router has a complete map of the global network and can choose the optimal path for every destination. Full Table suits enterprises with multiple upstreams that need granular routing control, but demands more router memory and CPU.
Default Route: The upstream sends only a single "0.0.0.0/0" default route, directing all traffic to the upstream for handling. This approach requires minimal router resources and is simple to configure — ideal for small-to-medium enterprises with a single upstream. The downside is that you cannot optimize routing for specific destinations.
In practice, a Partial Table approach is also available, where you receive routes only for specific regions or ASes, striking a balance between resource consumption and routing flexibility.
Benefits of Multi-Homing
Multi-homing means an enterprise connects to two or more upstream IP Transit providers simultaneously. It is a critically important design principle in enterprise network architecture, with key benefits including:
Redundancy and High Availability: When one provider experiences an outage or link failure, traffic automatically switches to another provider, ensuring business continuity. For enterprises requiring 99.5% or higher availability, multi-homing is virtually a necessity.
Route Optimization: Through BGP routing policies, enterprises can select different upstream paths based on destination networks. For example, traffic to Japan routes via the lowest-latency provider, while traffic to Europe goes through another. This is especially critical in cross-border business scenarios.
Negotiating Power: Enterprises with multiple upstreams have stronger bargaining leverage during renewals or capacity upgrades, avoiding lock-in to a single provider.
How to Choose an IP Transit Provider?
When selecting an IP Transit provider, enterprises should evaluate across several dimensions:
Network Coverage and Peering Quality: A provider's peering relationships and PoP distribution determine routing quality to various destinations. Providers with extensive peering deliver shorter paths and lower latency. Areapac operates self-managed BGP announcements in Beijing and Shanghai, directly controlling routing quality and providing precise mainland China egress routing for enterprise clients.
SLA and Technical Support: Enterprise-grade IP Transit should come with clear availability SLAs (typically 99.5% or above), latency guarantees, and incident response time commitments. 24/7 technical support is also essential, ensuring rapid recovery when outages occur outside business hours.
Bandwidth Flexibility: Traffic volumes fluctuate with seasons, events, and other factors. Providers should support elastic bandwidth adjustments, preventing enterprises from being locked into unnecessary capacity. Ideal providers offer 95th percentile billing, letting enterprises pay only for bandwidth actually used.
Compliance and Licensing: In regions like mainland China and Hong Kong, providers offering IP Transit must hold appropriate telecom licenses. Enterprises should verify providers' compliance credentials and avoid unauthorized grey-market channels.
IP Transit vs Other Access Methods
IP Transit is not the only egress option. Enterprises can also choose Peering and IXP (Internet Exchange Point) access. Peering is a settlement-free traffic exchange agreement between two networks, suited for large networks with symmetric traffic. IXPs are platforms where multiple networks exchange traffic at the same physical location, reducing transit costs. In practice, mature enterprises often combine IP Transit, Peering, and IXP access to achieve optimal cost-performance balance.
For most mid-sized enterprises, IP Transit remains the most straightforward and reliable global internet access method. Combined with Areapac's managed BGP services, enterprises can enjoy professional-grade route optimization and 24/7 monitoring support without building their own NOC team.