Cisco Crosswork Planning Design 7.2.x User Guide

Know about BGP routing details

Updated: August 14, 2026

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Describes the BGP routing mechanisms, including path selection algorithms, route advertisements, and inter-autonomous system communication for Internet-scale network routing decisions.

BGP multihop

Cisco Crosswork Planning automatically constructs BGP pseudonodes where necessary when BGP multihops are detected.

Cisco Crosswork Planning models the nodes in external ASes that are directly connected, for example, through eBGP, to nodes in internal ASes. One exception is that you can model BGP multihops by setting the node Type property to psn (pseudonode), such as might occur at a peering exchange. This pseudonode can represent the switch that connects a number of external AS nodes to the same internal AS node. In this instance, multiple external AS nodes are connected by circuits to a BGP psn node, and this node is connected to a node in the internal AS.

Note

In all cases, eBGP multipaths across parallel border circuits is assumed.

Configure BGP load balancing

Use this task to set BGP multipath options globally.

BGP load balancing to an external AS uses eBGP multipaths or eBGP multihops. Cisco Crosswork Planning models these two eBGP load balancing designs in the same manner, though in the UI they are identified only as multipaths. BGP multipath options are disabled by default.

Procedure

	1.	Open the plan file (refer to Open plan files). It opens in the Network Design page.
	2.	In the toolbar, click or choose Actions > Edit > Network options. The Network options page opens.
	3.	Click the Protocols tab.
	4.	In the BGP section, for each BGP multipath option that you want enabled, choose Enabled from the drop-down list. By default, all these options are disabled. EBGP multipath: Turns on eBGP multipath within the internal ASes. Demand routings through the internal AS to an external AS are divided among external routes with equal-cost BGP exit routes. EBGP multipath incoming: Turns on eBGP multipath in all external ASes. Demand routings from external ASes to an internal AS are divided among external routes with equal-cost BGP exit routes. IBGP multipath: Turns on iBGP multipath within the internal ASes. Demand routes through an internal AS to an external AS are divided among internal paths to equal-cost BGP exit routes.
	5.	Save the changes.

BGP multipath options are now enabled globally, allowing for load balancing across multiple equal-cost BGP paths.

BGP next hop

In networks, there are two common configurations for the BGP next-hop IGP metric used in the path selection. One is to set the next-hop self on the iBGP peers (next-hop self = on). The other is to configure IGP metrics on eBGP interfaces, and to inject the interface prefix into the IGP database by setting the interface to be a passive IGP interface (next-hop self = off).

Cisco Crosswork Planning does not have an explicit next-hop self setting, so it simulates paths as if next-hop self is off. That is, the IGP metric of the egress peering interface is included in the IGP distance to the peering router and is used in the iBGP path selection. However, next-hop self to an external AS can effectively be simulated by setting the metrics on all egress interfaces to that external AS to 0. You can set the IGP metric in either the Edit Interface or Edit Circuit page.

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