Cisco 6500 - Manual (Page 47)

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Cisco IOS Software Configuration Guide, Release 12.2SX
OL-13013-06
Chapter 4 Configuring Virtual Switching Systems
Configuring a VSS
Router(config-vs-domain)# dual-active detection pagp trust channel-group 20
Trusted port-channel 20 is not administratively down. To change the pagp dual-active trust
configuration, “shutdown” the port-channel first. Remember to “no shutdown” the
port-channel afterwards.
Configuring BFD Dual-Active Detection
For the BFD dual-active detection, you must configure dual-active interface pairs that will act as BFD
messaging links. By default, BFD detection is enabled.
To configure BFD dual-active detection, perform this task:
When you configure the dual-active interface pairs, note the following information:
• The individual ports must be configured first with both an IP address and BFD configuration. The
configuration is validated when you add the dual-active interface pair.
• The IP addresses assigned to the dual-active pair must be from two different networks or
subnetworks.
• The BFD timers must be configured with the same values on the ports at both ends of the link to
ensure proper operation of Layer 3 BFD dual-active detection.
• The MAC address cannot be specified on the interface.
Note We recommend that you configure a short BFD interval and small multiplier value (such as 50 to 100 ms
for the interval and 3 as the multiplier value). If the interval and multiplier values are large, there is a
long delay before the system initiates dual-active mode recovery. This condition can cause network
instability and poor convergence.
This example shows how to configure interfaces for BFD dual-active detection:
Router (config)# interface gigabitethernet 1/9/48
Router (config-if)# no switchport
Router (config-if)# ip address 200.230.230.231 255.255.255.0
Router (config-if)# bfd interval 100 min_rx 100 multiplier 3
Router (config-if)# no shutdown
Router (config-if)# interface gigabitethernet 2/1/48
Router (config-if)# no switchport
Router (config-if)# ip address 201.230.230.231 255.255.255.0
Router (config-if)# bfd interval 100 min_rx 100 multiplier 3
Router (config-if)# no shutdown
Router (config-if)# exit
Router (config)# switch virtual domain 100
Command Purpose
Step 1 Router(config)# switch virtual domain domain_id Enters virtual switch submode.
Step 2 Router(config-vs-domain)# dual-active detection bfd Enables BFD dual-active detection method. By
default, BFD detection is enabled.
Step 3 Router(config-vs-domain)# dual-active pair interface
int_1 interface int_2 bfd
Configures the dual-active pair of interfaces. The
interfaces int_1 and int_2 are of the form
type
1
switch/slot/port.
The interfaces must be directly connected (a single
Layer 3 hop).
1. type = fastethernet, gigabitethernet, or tengigabitethernet