nx.os.and.cisco.nexus.switching.2nd.edition.1587143046

scaling challenges as their IP networks grow. Another common option is for mergers and
acquisitions in which disparate networks are required to interconnect and share routing
information but lack a common administrative control.
BGP uses the concept of autonomous systems (AS) as delineation between networks. An AS
is a collection of routers under a common administrative control. Neighbor relationships are
manually configured between autonomous systems to exchange routing tables and apply
routing policy.
BGP is supported on both the Nexus 7000 and 5500 series switches. The Nexus 5500 series
switches must be configured with a Layer 3 daughtercard or module, dependent on the
specific platform. The Nexus 5500 series also requires an Enterprise License for BGP. The
examples in this chapter focus on BGP configuration for the Nexus 7000.
BGP Configuration
BGP within NX-OS is compatible with BGP on IOS and other IETF-compliant devices
enabling a smooth integration of Nexus equipment. Configuring BGP within NX-OS will be
similar, yet distinctly different in some aspects to traditional IOS configuration. These
differences are highlighted throughout the section.
Enabling BGP is a multistep process covered in detail. The following is a quick listing of
steps to enable a basic configuration of BGP:
1. Enable BGP.
2. Configure BGP routing process with the AS identification.
3. Configure address families.
4. Configure BGP neighbors.
5. Configure network routing policy.
6. Configure redistribution of other protocols if necessary.
7. Verify BGP operation.
The first step to configure BGP is to enable it on global configuration mode using the
feature command, as demonstrated in Example 3-77. With the modular nature of NX-OS,
using the feature command loads the BGP modular code into memory for execution.
Without the feature enabled, it would not be resident in memory. Figure 3-10 illustrates the
topology used for Examples 3-77 through 3-99.