H3C Technologies H3C MSR 50 - Manual (Page 73)

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can share traffic load if the VF owner resumes normal operation within this time. When this
timer times out, the master stops using the virtual MAC address corresponding to the failed AVF
to respond to ARP/ND requests from the hosts.
{
Timeout Timer—Duration that the new AVF takes over the VF owner. Before this timer times out,
all the routers in the VRRP group keep the failed AVF, and the new AVF forwards the packets
destined for the virtual MAC address corresponding to the failed AVF. When this timer times out,
all the routers in the VRRP group remove the failed AVF. The new AVF stops forwarding the
packets destined for the virtual MAC address corresponding to the failed AVF.
5. VF tracking
The AVF forwards packets destined to the MAC address of the AVF. If the uplink of the AVF fails
and no LVF is notified to take over the AVF role, hosts on the LAN that use the MAC address of the
AVF as their gateway MAC address cannot access the external network.
This problem can be solved by the VF tracking function. You can monitor the uplink state by using
NQA and BFD, and establish the collaboration between the VF and the NQA or between the VF
and the BFD through the tracking function. When the uplink fails, the state of the monitored track
entry changes to negative and the weight of the VF decreases by a specific value. Then, the VF
with a higher priority becomes the AVF and forwards packets.
The VF tracking function can also work on an LVF to monitor its corresponding AVF on another
router. When the AVF fails, the LVF immediately takes over the AVF to ensure uninterrupted
network communications.
Packet types
VRRP standard mode defines only VRRP advertisement. Only the master in a VRRP group periodically
sends VRRP advertisements, and the backups do not send VRRP advertisements.
VRRP load balancing mode defines the following types of packets:
• Advertisement—VRRP advertises VRRP group state and information about the VF that is in the active
state. Both the master and the backups periodically send VRRP advertisements.
• Request—If a backup is not the VF owner, it sends a request to ask the master to assign a virtual
MAC address.
• Reply—When receiving a request, the master sends a reply to the backup router to assign a virtual
MAC address. After receiving the reply, the backup router creates a VF for the virtual MAC address,
and becomes the owner of this VF.
• Release—When a VF owner fails, the router that takes over its responsibility sends a release after
a specified period of time to notify the other routers in the VRRP group to delete the VF of the failed
VF owner.
The format of these packets is similar to that of the advertisement in VRRP standard mode except that a
packet used in load balancing mode is appended with an option field, which contains information for
load balancing.
Configuring IPv4 VRRP
IPv4 VRRP configuration task list
To form a VRRP group, perform the following configurations on each device in the VRRP group.
Complete these tasks to configure IPv4 VRRP: