R3303-HP 6600/HSR6600 Routers Layer 3 - IP Routing Configuration Guide

242
Step Command Remarks
3. Enable the logging of session
state changes globally.
log-peer-change
Optional.
Enabled by default.
4. Enter BGP-VPN instance view.
ipv4-family vpn-instance
vpn-instance-name
Optional.
5. Enable the logging of session
state changes for a peer or
peer group.
peer { group-name | ip-address }
log-change
Optional.
Enabled by default.
Configuring BFD for BGP
BGP maintains neighbor relationships based on the keepalive timer and holdtime timer, which are set in
seconds. BGP defines that the holdtime interval must be at least three times the keepalive interval. This
mechanism makes link failure detection rather slow; once a failure occurs on a high-speed link, a large
quantity of packets are dropped. BFD resolves this issue by detecting links between neighbors quickly to
reduce convergence time upon link failures.
IMPORTANT:
•
Before you configure BFD for BGP, you must enable BGP.
• After a link failure occurs, BFD can detect the failure before the system performs GR. As a result, GR will
fail. If GR capability is enabled for BGP, use BFD with caution. If GR and BFD are both enabled, do no
t
disable BFD during a GR process; otherwise, GR might fail.
For BFD configuration, see High Availability Configuration Guide.
To enable BFD for a BGP peer:
Ste
p
Command Remarks
1. Enter system view.
system-view N/A
2. Enter BGP view or BGP-VPN
instance view.
• Enter BGP view:
bgp as-number
• Enter BGP-VPN instance view:
a. bgp as-number
b. ipv4-family vpn-instance
vpn-instance-name
Use either method.
3. Enable BFD for the specified
BGP peer.
peer ip-address bfd
Not enabled for any BGP peer
by default.
Displaying and maintaining BGP
Displaying BGP