[[["容易理解","easyToUnderstand","thumb-up"],["確實解決了我的問題","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["難以理解","hardToUnderstand","thumb-down"],["資訊或程式碼範例有誤","incorrectInformationOrSampleCode","thumb-down"],["缺少我需要的資訊/範例","missingTheInformationSamplesINeed","thumb-down"],["翻譯問題","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["上次更新時間：2025-09-05 (世界標準時間)。"],[],[],null,["# Configure the BGP identifier range for a Cloud Router\n=====================================================\n\nEach Cloud Router has a BGP identifier, also known as a *router ID* .\nThe BGP identifier is unique to each Cloud Router in your\nVirtual Private Cloud (VPC) network as required by [RFC\n6286](https://datatracker.ietf.org/doc/html/rfc6286). A BGP identifier is\na 4-octet unsigned integer, represented as a valid IPv4 address.\n\nYou can assign an explicit BGP identifier *range* to your Cloud Router.\nIf you do, your Cloud Router is assigned a stable BGP identifier from\nthe assigned range.\n\nAn explicit BGP identifier range is required for IPv6 BGP. If you add an IPv6\ninterface to a Cloud Router that doesn't already have a BGP identifier\nrange assigned, a random range from the IPv4 link-local address space is\nassigned to it.\n\nA Cloud Router without an explicit BGP identifier range is assigned a\nBGP identifier corresponding to the lexicographically-last IPv4 address among\nits IPv4 interfaces.\n\nBGP identifier changes and BGP session restarts\n-----------------------------------------------\n\nUnless you've configured an explicit BGP identifier range, Cloud Router\nmight change the automatically generated router ID in the following\ncircumstances:\n\n- You add a BGP session\n- You remove a BGP session\n- During periodic maintenance\n\nBefore you begin\n----------------\n\n### gcloud\n\nIf you want to use the command-line examples in this guide, do the following:\n\n1. Install or update to the latest version of the [Google Cloud CLI](/compute/docs/gcloud-compute).\n2. Set a [default region and\n zone](/compute/docs/gcloud-compute#set_default_zone_and_region_in_your_local_client).\n\n### API\n\nIf you want to use the API examples in this guide, set up\n[API access](/compute/docs/api/prereqs).\n\nAssign a BGP identifier range to Cloud Router\n---------------------------------------------\n\nThis section describes how to assign an explicit BGP identifier range to a\nCloud Router. \n\n### Console\n\n1. In the Google Cloud console, go to the **Create a Cloud Router**\n page.\n\n [Go to Create a\n Cloud Router](https://console.cloud.google.com/hybrid/routers/add)\n2. Specify the Cloud Router's details:\n\n - **Name** : The name of the Cloud Router. This name is displayed in the Google Cloud console and is used by the Google Cloud CLI to reference the Cloud Router---for example, `my-router`.\n - **Description**: Optional. A description of the Cloud Router.\n - **Network** : The VPC network that contains the instances that you want to reach---for example, `my-network`.\n - **Region** : The region where you want to locate the Cloud Router---for example, `asia-east1`.\n -\n **Google ASN** : Any\n [private ASN](https://tools.ietf.org/html/rfc6996)\n (`64512`-`65534`,\n `4200000000`-`4294967294`) that you aren't already\n using in the on-premises network. Cloud Router requires that\n you use a private ASN, but your on-premises ASN can be public or\n private.\n\n\n | **Note:** If you are using Cloud Router with Partner Interconnect, you must specify the Google-owned public ASN `16550` instead.\n\n \u003cbr /\u003e\n\n - **BGP peer keepalive interval** : The interval between two successive BGP keepalive messages that are sent to the peer router. This value must be an integer between 20 and 60 that specifies the number of seconds for the interval. The default is 20 seconds. For more information, see [Manage BGP\n timers](/network-connectivity/docs/router/how-to/managing-bgp-timers).\n -\n **BGP identifier** : Optional. The BGP identifier, sometimes called a\n *router ID*, that uniquely identifies a Cloud Router in a\n network. If omitted, Cloud Routers with IPv4 BGP sessions use\n one of the IPv4 BGP addresses as the BGP identifier, and adding the\n first IPv6 interface to this Cloud Router populates the field\n automatically.\n\n\n For more\n information, see\n [Configure the BGP\n identifier range for a Cloud Router](/network-connectivity/docs/router/how-to/configure-bgp-identifier).\n3. Optional: To specify custom advertised routes, go to the **Advertised routes** section. For more information, see [Advertised routes](/network-connectivity/docs/router/concepts/advertised-routes).\n 1. To specify custom **Routes** , select **Create custom routes**.\n 2. Choose whether to advertise the subnets visible to the Cloud Router. Enabling this option mimics the Cloud Router's default behavior.\n 3. To add an advertised route, select **Add a custom route**, and then configure it.\n4. To save your settings and create a Cloud Router, click **Create**. Your new Cloud Router appears on the Cloud Router listing page. To view its details and to configure a BGP session, select it.\n\n### gcloud\n\nTo assign an explicit BGP identifier range when you create the\nCloud Router, use the `--bgp-identifier-range` flag. \n\n```\ngcloud compute routers create ROUTER_NAME \\\n --bgp-identifier-range=BGP_IDENTIFIER_RANGE\n```\n\nReplace \u003cvar translate=\"no\"\u003eBGP_IDENTIFIER_RANGE\u003c/var\u003e with a link-local IPv4 range\nfrom `169.254.0.0/16` with a subnet mask prefix length of at most `/30`.\nThe IPv4 address range must not overlap either of the following:\n\n- The IPv4 address range used by another BGP session on this\n Cloud Router.\n\n- Any custom BGP identifier range used by another\n Cloud Router in the same VPC network and region.\n\n### API\n\nUse the\n[`routers.insert` method](/compute/docs/reference/rest/v1/routers/insert): \n\n```\n POST https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/regions/REGION/routers/ROUTER_NAME\n {\n \"bgp\": {\n \"asn\": \"ASN_NUMBER\",\n \"keepaliveInterval\": KEEPALIVE_INTERVAL,\n \"identifierRange\": BGP_IDENTIFIER_RANGE\n },\n \"name\": \"ROUTER_NAME\",\n \"network\": \"NETWORK\"\n }\n```\n\nReplace \u003cvar translate=\"no\"\u003eBGP_IDENTIFIER_RANGE\u003c/var\u003e with a link-local IPv4 range\nfrom `169.254.0.0/16` with a subnet mask prefix length of at most `/30`. The\nrange must not overlap with any existing IPv4 Cloud Router\ninterface or a BGP identifier range of a Cloud Router in the same\nregion.\n\nModify the BGP identifier range\n-------------------------------\n\nThis section describes how to modify an existing explicit BGP identifier\nrange on a Cloud Router.\n**Caution:** Changing the explicit BGP identifier range of Cloud Router causes all existing BGP sessions to restart for all BGP peers on the Cloud Router. \n\n### gcloud\n\nTo change the explicit BGP identifier range, run the following command. \n\n```\ngcloud compute routers update ROUTER_NAME \\\n --bgp-identifier-range=BGP_IDENTIFIER_RANGE\n```\n\nReplace \u003cvar translate=\"no\"\u003eBGP_IDENTIFIER_RANGE\u003c/var\u003e with a link-local IPv4 range\nfrom `169.254.0.0/16` with a subnet mask prefix length of at most `/30`.\n\nThe IPv4 address range must not overlap either of the following:\n\n- The IPv4 address range used by another BGP session on this\n Cloud Router.\n\n- Any custom BGP identifier range used by another\n Cloud Router in the same VPC network and region.\n\n### API\n\nUse the\n[`routers.patch` method](/compute/docs/reference/rest/v1/routers/patch)\nto update the `bgp.identifierRange` field: \n\n```\n PATCH https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/regions/REGION/routers/ROUTER_NAME\n {\n \"bgp\": {\n \"identifierRange\": BGP_IDENTIFIER_RANGE\n }\n }\n```\n\nReplace \u003cvar translate=\"no\"\u003eBGP_IDENTIFIER_RANGE\u003c/var\u003e with a link-local IPv4 range\nfrom `169.254.0.0/16` with a subnet mask prefix length of at most `/30`.\nThe IPv4 address range must not overlap either of the following:\n\n- The IPv4 address range used by another BGP session on this\n Cloud Router.\n\n- Any custom BGP identifier range used by another\n Cloud Router in the same VPC network and region.\n\nWhat's next\n-----------\n\n- [View Cloud Router details](/network-connectivity/docs/router/how-to/viewing-router-details)"]]
