Interconnects provide connectivity between the GGC Router and an ISP’s router. The interconnect can be a single physical port or several physical ports aggregated in a LACP bundle.
Google provides required SFPs and DACs with GGC equipment. No other SFPs and DACs are supported and you must not use them with GGC equipment. Google doesn’t provide SFPs for the ISP's side of interconnects.
Multiple Interconnects
Usually, having a single interconnect is enough. However, it is possible to configure up to four interconnects between the GGC router and your network.
When configuring more than one interconnect SP is required to mark at least one interconnect as a "default route". Marking an interconnect as a "default route" creates a static default route on the GGC router, which is then used for GGC to Google traffic. All interconnects that are expected to carry GGC to Google traffic must be marked as "default route".
When adding a new interconnect make sure it is tagged as a "default route" only when the remote (ISP) side is ready to carry traffic, otherwise it might cause service impact. See Commonly Requested Interconnect Changes section below for details.
If the same prefix is advertised via different interconnects, we will load balance egress.
Interconnects of different capacity are supported on a single GGC router, but Google is unable to perform congestion avoidance on unbalanced interconnects. ISPs that want to have unbalanced interconnects need to make sure prefixes are appropriately split-advertised between interconnects.
Google doesn’t support an interconnect that will only be connected when the main connection is down (cold standby). If a configured interconnect is down, it triggers an alarm. We expect all links to be up.
Commonly Requested Interconnect Changes
Please find below the list of commonly requested interconnect changes and the high-level overview of the suggested way of implementing them.
GGC router configuration changes can be requested in the ISP portal changes by going to the Configuration tab of relevant GGC node, pressing Update Configuration button and following the prompts.
Adding an Interconnect
- Add a new interconnect without marking it "default route"
- As noted above, marking an interconnect with "default route" will create a static default route on the GGC router and might cause connectivity issues if there are any issues with the new interconnect (see next step).
- Perform basic connectivity test on new interconnect
- You may want to ensure GGC side is reachable (ICMP echo)
- You may want to ensure relevant BGP session comes up, etc
- Once basic connectivity over the new interconnect is confirmed, request another GGC router change to mark the new interconnect as "default route" (if it is expected to carry GGC to Google traffic).
Migrate from Nx10G to Nx100G Interconnect
- Add Nx 100G interconnect alongside existing Nx 10G interconnect - follow instructions in Additional Interconnect section above.
- Once Nx 100G interconnect is ready and is carrying traffic, remove Nx 10G interconnect.
Migrate from non-LACP to LACP Interconnect
LACP is automatically enabled on the GGC side for interconnects that have more than one physical port. LACP is disabled by default on single port interconnects, but can be force-enabled.
LACP-enabled interconnects on GGC router are configured with the LACP fallback feature. That means if LACP is disabled on the ISP side, GGC router will fallback on using a single (usually lowest port number on GGC router) physical port in the LACP bundle without LACP. LACP fallback feature makes going from non-LACP to LACP interconnects easy.
- Request LACP enabled on GGC side.
- Once GGC side is done, enable LACP on ISP side.