Cisco 7206 Network Configuration Guide - Page 228

Information About vPCs Chapter 7 Configuring vPCs Send document comments to [email protected] In addition, you can use the priority command in the if-hsrp configuration mode to configure failover thresholds for when a group state enabled on a vPC peer link is in standby or in listen state. You can configure lower and upper thresholds to prevent the interface from going up and down. VRRP acts similarly to HSRP when running on vPC peer devices. You should configure VRRP the same way that you configure HSRP. For GLBP, the forwarders on both vPC peer devices forward traffic. When the primary vPC peer device fails over to the secondary vPC peer device, the FHRP traffic continues to flow seamlessly. We recommend that you configure routing adjacency between the two vPC peer devices to act as a backup routing path. If one vPC peer device looses Layer 3 uplinks, vPC can redirect the routed traffic to the other vPC peer device and leverage its active Layer 3 uplinks. You can configure the inter-switch link for backup routing path in the following ways: • Create a Layer 3 link between the 2 vPC peer devices. • Use the non-VPC VLAN trunk with a dedicated VLAN interface. • Use vPC peer link with a dedicated VLAN interface. We do not recommend configuring the burnt-in MAC address option (use-bia) for HSRP or manually configuring virtual MAC addresses for any FHRP protocol in a vPC environment because these configurations can adversely affect the vPC load balancing. The hsrp use-bia is not supported on vPCs. When you are configuring custom MAC addresses, you must configure the same MAC address on both vPC peer devices. Beginning with Cisco NX-OS Release 4.2(1), you can configure a restore timer that will delay the vPC coming back up until after the peer adjacency forms and the VLAN interfaces are back up. This feature avoids packet drops when the routing tables may not be converged before the vPC is once again passing traffic. Use the delay restore command to configure this feature. To delay the VLAN interfaces on the restored vPC peer device from coming up, use the interfaces-vlan option to the delay restore command. See the Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide, Release 5.x, for more information on FHRPs and routing. CFSoE The Cisco Fabric Services over Ethernet (CFSoE) is a reliable state transport mechanism that is used to synchronize the actions of the vPC peer devices. CFSoE carries messages and packets for many features linked with vPC, such as STP and IGMP. Information is carried in CFS/CFSoE protocol data units (PDUs). When you enable the vPC feature, the device automatically enables CFSoE, and you do not have to configure anything. CFSoE distributions for vPCs do not need the capabilities to distribute over IP or the CFS regions. You need not configure anything for the CFSoE feature to work correctly on vPCs. The CFSoE transport is local to each VDC. You can use the show mac address-table command to display the MAC addresses that CFSoE synchronizes for the vPC peer link. Note Do not enter the no cfs eth distribute or the no cfs distribute command. You must enable CFSoE for vPC functionality. If you do enter either of these commands with vPC enabled, the system displays an error message. 7-26 Cisco Nexus 7000 Series NX-OS Interfaces Configuration Guide, Release 5.x OL-23435-03