Cisco Nexus 7000 Series - Tuning BGP

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Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide, Release 4.x
OL-20002-02
Chapter 11 Configuring Advanced BGP
Configuring Advanced BGP
This example shows how to enable advertising and receiving IPv4 and IPv6 routes for multicast RPF for
a neighbor.:
switch# config t
switch(config)# interface ethernet 2/1
switch(config-if)# ipv6 address 2001:0DB8::1
switch(config-if)# router bgp 65536
switch(config-router)# neighbor 192.168.1.2 remote-as 35537
switch(config-router-neighbor)# address-family ipv4 multicast
switch(config-router-neighbor-af)# exit
switch(config-router-neighbor)# address-family ipv6 multicast
switch(config-router-neighbor-af)# copy running-config startup-config
Tuning BGP
You can tune BGP characteristics through a series of optional parameters.
To tune BGB, use the following optional commands in router configuration mode:
Command Purpose
bestpath [always-compare-med |
compare-routerid | med {missing-as-worst |
non-deterministic}]
Example:
switch(config-router)# bestpath
always-compare-med
Modifies the best-path algorithm. The optional
parameters are as follows:
• always-compare-med—Compares MED on
paths from different autonomous systems.
• compare-routerid—Compares the router IDs
for identical eBGP paths.
• med missing-as-worst—Treats a missing
MED as the highest MED.
• med non-deterministic—Does not always
pick the best MED path from among the paths
from the same autonomous system.
enforce-first-as
Example:
switch(config-router)# enforce-first-as
Enforces the neighbor autonomous system to be the
first AS number listed in the AS_path attribute for
eBGP.
log-neighbor-changes
Example:
switch(config-router)#
log-neighbor-changes
Generates a system message when a neighbor
changes state.