GCP Partner Interconnect FAQs

Quick answers to the questions most often asked about connecting to Google Cloud with IZO™+ Multi Cloud Connect. For step-by-step detail, follow the linked pages.

Getting connected

How do I start a Google Cloud connection?

In your Google Cloud console you create a Partner Interconnect VLAN attachment, which produces a pairing key, and you share that key with Tata Communications via the TC^x Portal. See GCP Partner Interconnect Setup (Direct interconnect).

What is a pairing key?

It is the value Google generates when you create a VLAN attachment; it links your attachment to the service provider. A key ending in /1 is Zone 1 (primary) and one ending in /2 is Zone 2 (secondary).

Which connection paths are available?

A Tata Communications-managed direct interconnect (50 Mbps–50 Gbps) and a partner-routed path (up to 10 Gbps). See Google Cloud Interconnect Overview.

Bandwidth and attachments

What bandwidths are available?

Standard tiers are 50, 100, 200, 300, 400, 500 Mbps and 1, 2, 5, 10 Gbps, with 20 and 50 Gbps where 100 Gbps ports are available (direct path). The partner-routed path supports up to 10 Gbps in standard slabs.

Can I change bandwidth without downtime?

Yes. Google supports a hot bandwidth change of a VLAN attachment; Tata Communications applies it without tearing the attachment down (and in place on the partner exchange for the partner-routed path).

How many VLAN attachments can I have?

A 10 Gbps interconnect supports 16 by default (up to 25 via the console); a 100 Gbps interconnect supports 75 by default. Google permits oversubscription up to 3x. These are per-port defaults; the quota can be raised by submitting a quota-increase request to Google.

Routing and peering

What ASNs are used?

Google uses 16550 (default for Partner Interconnect); Tata Communications uses 4755 (fixed).

Does GCP support public peering?

No. Google Cloud Partner Interconnect offers private peering only.

Who assigns the BGP peering IPs and the VLAN ID?

Google does, on the attachment – the peering addresses come from Google’s link-local range, and the VLAN ID is assigned by Google (you cannot specify it). The peering IPs come from a link-local /29, and there is nothing for you to enter.

Is multicast supported?

No. Multicast is not supported on Partner Interconnect VLAN attachments.

Service types

What’s the difference between Layer 3 and Layer 2?

On Layer 3, Tata Communications runs the BGP to Google (4755 <--> 16550) and you reach GCP over the L3VPN; Google assigns the addressing. On Layer 2, Tata Communications provides transparent point-to-point L2VPN tunnels and you manage IP and BGP directly with Google. See GCP L2VPN Services.

Who manages the CPE?

The cloud connection is delivered as an unmanaged service, so CPE configuration sits with you, using the parameters Google and Tata Communications provide.

Still stuck?

If your question isn’t answered here, see GCP Troubleshooting for symptom-based diagnostics, or raise a ticket from the Support area of the TC^x Portal.