Configuring BGP

Where can I find the BGP configuration for a GGC node?

BGP details for each node are shown in the ISP Portal Asset view.

For deployments where you manage the GGC network devices (switches and routers)

BGP configurations for AS11344 peering (GGC):

  • Our ASN is 11344 (AS65535 is also used for some older deployments).
  • BGP is terminated on one of the GGC servers.
  • Your device must be configured in Passive mode. We do not accept incoming BGP connections to the GGC servers.
  • eBGP Multi-Hop is supported.
  • BGP is used only for us to receive a list of user prefixes.
  • BGP is not used for traditional routing. The GGC servers use a default route (first usable IP in the GGC range)
  • We do not advertise any prefixes to you.
  • A maximum of two BGP sessions with AS11344 are permitted at a single GGC node; one for IPv4 and one for IPv6. Consider using a route server if you need to advertise aggregated prefix data from multiple sources on your network.
  • The maximum prefix size considered by a GGC node is /27 for direct advertisements and /24 for indirect advertisements. For IPv6, the maximum prefix size is /56.

For deployments where Google supplies and manages the network devices (switches and routers)

BGP Configurations for AS36040 peering:

  • Our ASN is 36040.
  • BGP is terminated on our router.
  • Your device may be in Active or Passive mode.
  • eBGP Multi-Hop is supported. Our router will need a route to your BGP peer, either static or via another BGP session.
  • BGP is used both for receiving a list of user prefixes, and for traditional routing.
  • We may advertise the prefix of the the GGC servers to you. You should propagate this advertisement to your users, peers and transit providers.
  • Multiple BGP sessions with AS36040 are permitted at a single location.

Additional BGP configuration

  • MD5 passwords are supported, but not required, for GGC BGP sessions.
  • Multi Exit Discriminators (MED) are not supported. BGP community tags allow you to provide additional signals to us about prefixes originating in your network. This includes indicating serving preferences for traffic ingressing your network from GGC and peering. For more information, refer to BGP Community Support For Google Serving.

Prefix advertisements to the GGC node

You should advertise all your user prefixes to the GGC node. If you have peers and downstream customers, you may advertise their prefixes too.

For more complex deployments, see the article on multi-node configurations.

Prefix advertisements to upstreams 

You should ensure that user prefixes advertised to GGC nodes are also advertised upstream (at AS15169 peering, and via your transit providers), with the same prefix lengths.

Common misconfigurations, which can result in undesirable traffic flows, include:

  • User prefixes seen at GGC, but missing from advertisements to AS15169 or transit
  • User prefixes advertised more specifically at peering / transit than at GGC

You can view information on how we see your prefixes on the ISP portal BGP pages.

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