Руководство По Проектированию для Cisco Cisco Nexus 5010 Switch
Design Guide
© 2010 Cisco Systems, Inc. All rights reserved. This document is Cisco Public Information.
Page 25 of 28
HSRP Configuration and Best Practices for vPC
The configuration on the primary Cisco Nexus 7000 Series device looks like this:
interface vLAN50
no shutdown
ip address 10.50.0.251/24
hsrp 50
preempt delay minimum 180
priority 150
timers 1 3
ip 10.50.0.1
The configuration on the secondary Cisco Nexus 7000 Series device looks as follows:
interface vLAN50
no shutdown
ip address 10.50.0.252/24
hsrp 50
preempt delay minimum 180
priority 130
timers 1 3
ip 10.50.0.1
The most significant difference between the HSRP implementation of a non-vPC configuration compared with a vPC
configuration is that the HSRP MAC addresses of a vPC configuration are programmed with the G (gateway) flag on
both systems, compared with a non-vPC configuration where only the active HSRP interface can program the MAC
address with the G flag.
configuration is that the HSRP MAC addresses of a vPC configuration are programmed with the G (gateway) flag on
both systems, compared with a non-vPC configuration where only the active HSRP interface can program the MAC
address with the G flag.
Given this fact, routable traffic can be forwarded by both the vPC primary device (where HSRP is primary) and the
vPC secondary device (where HSRP is secondary), with no need to send this traffic to the HSRP primary device.
vPC secondary device (where HSRP is secondary), with no need to send this traffic to the HSRP primary device.
Without this flag, traffic sent to the MAC address would not be routed.
The following CLI captures show the MAC address table programming on the vPC peer that is HSRP active for a
given VLAN and the vPC peer that is HSRP standby for that same VLAN.
given VLAN and the vPC peer that is HSRP standby for that same VLAN.
vPC HSRP on active:
G - 0000.0c07.ac01 static
vPC HSRP on standby:
G - 0000.0c07.ac01 static
In a non-vPC environment, the HSRP MAC looks as follows:
On Active: G - 0000.0c07.ac01 static
On Standby: * - 0000.0c07.ac01 static
Layer 3 Link Between vPC Peers
In vPC designs, you should make sure to include a Layer 3 link or VLAN between the Cisco Nexus 7000 Series
systems so that the routing areas are adjacent. Also, you may consider HSRP tracking in non-vPC designs, but not in
vPC designs.
systems so that the routing areas are adjacent. Also, you may consider HSRP tracking in non-vPC designs, but not in
vPC designs.
HSRP tracking is not recommended for the reasons illustrated in Figure 13. Imagine that traffic from n5k on VLAN60
needs to be routed to n5k on VLAN 50. As a result of core links failure, HSRP tracking shuts down the SVI 60 on
needs to be routed to n5k on VLAN 50. As a result of core links failure, HSRP tracking shuts down the SVI 60 on