Reference Guide

• Server racks, Rack 1 and Rack 2, are part of data centers DC1 and DC2, respectively.
• Rack 1 is connected to devices A1 and B1 in L2 network segment.
• Rack 2 is connected to devices A2 and B2 in L2 network segment.
• A VLT LAG is present between A1 and B1 as well as A2 and B2.
• A1 and B1 connect to core routers, C1 and D1 with VLT routing enabled.
• A2 and B2 connect to core routers, C2 and D2, with VLT routing enabled.
• The core routers C1 and D1 in the local VLT domain connect to the core routers C2 and D2 in the remote VLT Domain using VLT links.
• The core routers C1 and D1 in local VLT Domain along with C2 and D2 in the remote VLT Domain are part of an L3 cloud.
• The core routers C1, D1, C2, D2 are in a VRRP group with the same vrrp-group ID.
When a virtual machine running in Server Rack 1 migrates to Server Rack 2, L3 packets for that VM are routed through the default
gateway.
Sample conguration of C1:
• Congure VRRP on L2 links between core routers:
C1(config)# interface vlan 100
C1(conf-if-vl-100)# ip address 10.10.100.1/24
C1(conf-if-vl-100)# vrrp-group 10
C1(conf-vlan100-vrid-10)# priority 250
C1(conf-vlan100-vrid-10)# virtual-address 10.10.100.5
• Congure VLT port channel for VLAN 100:
C1(config)# interface port-channel 10
C1(conf-if-po-10)# vlt-port-channel 10
C1(conf-if-po-10)# switchport mode trunk
C1(conf-if-po-10)# switchport trunk allowed vlan 100
C1(conf-if-po-10)# exit
• Add members to port channel 10:
C1(config)# interface ethernet 1/1/3
C1(conf-if-eth1/1/3)# channel-group 10
C1(conf-if-eth1/1/3)# exit
C1(config)# interface ethernet 1/1/4
C1(conf-if-eth1/1/4)# channel-group 10
C1(conf-if-eth1/1/4)# exit
• Congure OSPF on L3 side of core router:
C1(config)# router ospf 100
C1(conf-router-ospf-100)# exit
C1(config)# interface vlan 200
C1(conf-if-vl-200)# ip ospf 100 area 0.0.0.0
• Congure VLT port channel for VLAN 200:
C1(config)# interface port-channel 20
C1(conf-if-po-20)# vlt-port-channel 20
C1(conf-if-po-20)# switchport mode trunk
C1(conf-if-po-20)# switchport trunk allowed vlan 200
C1(conf-if-po-20)# exit
• Add members to port channel 20:
C1(config)# interface ethernet 1/1/5
C1(conf-if-eth1/1/5)# channel-group 20
C1(conf-if-eth1/1/5)# exit
C1(config)# interface ethernet 1/1/6
C1(conf-if-eth1/1/6)# channel-group 20
C1(conf-if-eth1/1/6)# exit
Sample conguration of D1:
• Congure VRRP on L2 links between core routers:
D1(config)# interface vlan 100
D1(conf-if-vl-100)# ip address 10.10.100.2/24
D1(conf-if-vl-100)# vrrp-group 10
D1(conf-vlan100-vrid-10)# virtual-address 10.10.100.5
608
Virtual link trunking