A cloud connection can be delivered two ways: over a direct interconnect, where Tata Communications connects straight to the cloud provider, or over an interconnection partner-routed connection, where the connection is carried through a partner network to the cloud. Direct interconnects support the fullest set of capabilities; interconnection partner-routed connections trade some of that flexibility for reach where a direct interconnect is not available.
What “connectivity option” decides
Both options give you private access to the cloud. The difference is the path between the Tata Communications backbone and the cloud provider’s edge:
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A direct interconnect is a connection established directly between the Tata Communications network and the cloud provider at a peering location.
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An interconnection partner-routed connection rides through an intermediate partner network to reach the cloud provider, which is useful where a direct interconnect to that cloud or location is not present.
Direct interconnect
A direct interconnect is the default where it is available. It supports both routed (Layer 3) and point-to-point (Layer 2) connections, the full range of bandwidth tiers, and dual-path resilience patterns. Routing parameters such as the Tata Communications and cloud-provider autonomous-system numbers are well defined, and resilient designs use standard BGP attribute tuning so that one path is primary and another secondary.
Interconnection Partner-routed connection
An interconnection partner-routed connection reaches the cloud through a partner network. It extends coverage, but it comes with constraints that follow from crossing an intermediate network:
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The connection is carried as a Layer 2 tunnel across the backbone, with Tata Communications allocating an outer service tag from a reserved range for each interconnect with the partner network.
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Some Layer 2 modes are not supported across the partner path. For example, connecting multiple sites in a single Layer 2 domain is not available, and certain VLAN-transparency and Q-in-Q modes do not apply.
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Resilience options can be more limited than on a direct interconnect; in some cases only a single (primary) connection is available via the partner network.
Because of these constraints, an interconnection partner-routed connection is best treated as a reach option for clouds or locations where a direct interconnect is not present, rather than as a like-for-like substitute.
How to tell which applies to you
The available option depends on the cloud provider and the peering location you choose. The per-cloud sections state which option applies for each cloud and call out any limitations on bandwidth, resilience or Layer 2 behaviour for the interconnection partner-routed path.
Tata Communications - allocated parameters (reference)
|
Parameter |
Standard value |
|
Tata Communications ASN |
4755 (fixed) |
|
interconnection Partner-routed outer service-tag range |
1300 to 1399 (one per interconnect) |
|
Resilient-path BGP local preference |
400 / 300 / 200 / 100 (primary to quaternary) |
|
AS-PATH prepend on secondary path |
4755 2 |
What’s on the cloud side
Selecting the connectivity option, generating any service key, and creating the connection request are done in the cloud provider’s console; for those cloud-side steps, see the relevant per-cloud section. Tata Communications uses the details you generate there to provision the connection on the backbone.
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