06-14-2012 09:24 AM
We have GLBP configured on two Nexus 7000's using "load-balancing host-dependant" as our method of balancing. My question is, is there a quick way to determine which router each host is using. These are in production so any debugging is frowned on.
Thanks
David
Solved! Go to Solution.
06-15-2012 06:35 AM
Available command to verify GLBP operation is following
show glbp [group group-number]
Displays the GLBP status for all or one group.
show glbp capability
Displays the GLBP capability for all or one group.
show glbp interface interface-type slot/port
Displays the GLBP status for an interface.
show glbp interface interface-type slot/port [active] [disabled] [init] [listen] [standby]
Displays the GLBP status for a group or interface for virtual forwarders in the selected state.
show glbp interface interface-type slot/port [active] [disabled] [init] [listen] [standby] brief
Displays a brief summary of the GLBP status for a group or interface for virtual forwarders in the selected state.
But none of these will show you which host uses which AVF. In GLBP, Hosts still point to a default gateway IP address, but GLBP causes different hosts to send their traffic to one of up to four routers in a GLBP group. To do so, the GLBP Active Virtual Gateway (AVG) assigns each router in the group a unique virtual MAC address format 0007.B400.xxyy, where xx is the GLBP group number, and yy is a different number for each router (01, 02, 03, or 04). When a client ARPs for the (virtual) IP address of its default gateway, the GLBP AVG replies with one of the four possible virtual MACs. By replying to ARP requests with different virtual MACs, the hosts in that subnet will in effect balance the traffic across the routers, rather than send all traffic to the one active router. You can check ARP table of host and see the mac address of default gateway. But this is not an easy way.
06-15-2012 06:35 AM
Available command to verify GLBP operation is following
show glbp [group group-number]
Displays the GLBP status for all or one group.
show glbp capability
Displays the GLBP capability for all or one group.
show glbp interface interface-type slot/port
Displays the GLBP status for an interface.
show glbp interface interface-type slot/port [active] [disabled] [init] [listen] [standby]
Displays the GLBP status for a group or interface for virtual forwarders in the selected state.
show glbp interface interface-type slot/port [active] [disabled] [init] [listen] [standby] brief
Displays a brief summary of the GLBP status for a group or interface for virtual forwarders in the selected state.
But none of these will show you which host uses which AVF. In GLBP, Hosts still point to a default gateway IP address, but GLBP causes different hosts to send their traffic to one of up to four routers in a GLBP group. To do so, the GLBP Active Virtual Gateway (AVG) assigns each router in the group a unique virtual MAC address format 0007.B400.xxyy, where xx is the GLBP group number, and yy is a different number for each router (01, 02, 03, or 04). When a client ARPs for the (virtual) IP address of its default gateway, the GLBP AVG replies with one of the four possible virtual MACs. By replying to ARP requests with different virtual MACs, the hosts in that subnet will in effect balance the traffic across the routers, rather than send all traffic to the one active router. You can check ARP table of host and see the mac address of default gateway. But this is not an easy way.
06-15-2012 06:45 AM
Thanks Krun...You've confirmed what I thought. There is no easy way.
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