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Modifying Global BGP Settings for a BGP Router

Owned by Alex Mandel
Jul 19, 2023
3 min read

Specify the following:

  • ASN: Specify the ASN (autonomous system number) of the interface. Use the up and down arrows, or manually enter a value from 1 to 4294967295. BGP uses the unique ASN to identify each system. BloxOne supports up to four-byte ASNs, including ASPLAIN and ASDOT formats.

  • Router ID: Enter the router ID, which is a 4-byte field that is set to the highest IP address on the router. It is used in the BGP algorithm to determine the best path to a destination, and the preference is for the BGP router with the lowest router ID. By using a configured hold time and KEEPALIVE messages, the BGP mechanism ensures that the BGP neighbors are still alive.

  • In the ADDRESS FAMILY section, specify the following:

    • IPv4:

      • ADMIN DISTANCE: An administrative distance or route preference is a rating of trustworthiness of a source of routing information. It is the first criterion that a router uses to determine the routing protocol to be used if two protocols provide the route information for the same destination. An administrative distance has only local significance and is not advertised in routing-related updates.

        • External: This is optional. The range is 1 to 255.

        • Internal: This is optional. The range is 1 to 255.

        • Local: This is optional. The range is 1 to 255.

      • Maximum Paths eBGP: This setting determines if and when a router will add multiple eBGP routes to the IP routing table. Enter the number of possible IP routes learned from eBGP. This is optional. The range is 1 to 64.

      • Maximum Paths iBGP: This setting determines if and when a router will add multiple iBGP routes to the IP routing table. Enter the number of possible IP routes learned from iBGP. This is optional. The range is 1 to 64.

      • AGGREGATE ADDRESSES:

        1. Click Add.

        2. In the ADDRESS/CIDR column, specify a valid IPv4 prefix.

        3. In the OPTIONS column, select Summary Only, AS-Set, or both.

    • IPv6:

      • ADMIN DISTANCE:

        • External: This is optional. The range is 1 to 255.

        • Internal: This is optional. The range is 1 to 255.

        • Local: This is optional. The range is 1 to 255.

      • Maximum Paths eBGP: This setting determines if and when a router will add multiple eBGP routes to the IP routing table. Enter the number of possible IP routes learned from eBGP. This is optional. The range is 1 to 64.

      • Maximum Paths iBGP: This setting determines if and when a router will add multiple iBGP routes to the IP routing table. Enter the number of possible IP routes learned from iBGP. This is optional. The range is 1 to 64.

      • AGGREGATE ADDRESSES:

        1. Click Add.

        2. In the ADDRESS/CIDR column, specify a valid IPv6 prefix.

        3. In the OPTIONS column, select Summary Only, AS-Set, or both.

  • In the INJECT ROUTES section, do the following (optional):

    • Click Add.

    • In the IP ADDRESSES column, specify a valid IPv4 or IPv6 prefix.

  • In the ADVANCED section, expand the Advanced Options drop-down and specify the following:

    • Fast External Failover: If the route used to reach the peer is invalid or goes offline, toggle this to Enabled to terminate external BGP sessions of any directly adjacent peer, without waiting for the hold-down timer to expire. Toggle this to Disabled to disable fast external failover. By default, this option is set to Disabled.

    • Graceful Restart: Toggle this to Enabled to announce a graceful restart. If you toggle this to Disabled, the graceful restart capability is not announced. By default, this option is set to Disabled.

    • Graceful Shutdown: Toggle this to Enabled to announce a graceful shutdown. If you toggle this to Disabled, the graceful restart capability is not announced. By default, this option is set to Disabled.

    • Log Neighbor Changes: Toggle this to Enabled to log changes from a BGP neighbor. By default, this option is set to Disabled.

    • Hold Time: Enter a value from 1 to 65535. This is the number of seconds that a router will wait for incoming BGP messages before it assumes the neighbor is dead. This heartbeat mechanism ensures that the BGP neighbors are healthy and alive. The hold time you enter here sets the hold timer for each BGP neighbor. Upon receipt of an UPDATE or a KEEPALIVE message, the hold timer resets to the initial value. If the hold timer reaches zero, the BGP session is terminated, the routing paths from that neighbor are removed, and, for the prefixes affected, an appropriate message about withdrawal of an update route is sent to other BGP neighbors.

    • Keep Alive: Enter a value from 1 to 65535. This is the number of seconds for the time interval during which a router sends KEEPALIVE messages to the BGP neighbors, to keep the BGP session alive. Typically, the keep alive timer is one-third of the hold time.

    • Update Delay: Enter the number of seconds for the minimum delay between updates for a neighbor session.

Click Next.