Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 689)

Multi-Service IronWare Switching Configuration Guide 659
53-1003036-02
MCT for VRRP or VRRP-E
18
MCT for VRRP or VRRP-E
One MCT switch is the VRRP or VRRP-E master router
and the other MCT switch is VRRP or VRRP-E
backup router
The MCT switch that acts as backup router needs to ensure that packets sent to a VRRP-E virtual IP
address can be L2 switched to the VRRP-E master router for forwarding. The MCT switch that acts
as master router will sync the VRRP-E MAC to the other MCT switch that acts as backup router. Both
data traffic and VRRP-E control traffic travel through the ICL unless the short-path forwarding
feature is enabled.
L3 traffic forwarding from CEP ports to CCEP ports
Traffic destined to the CCEP ports from the client or CEP ports follow the normal IP routing on both
master and backup routers. By default, the best route should not involve the ICL link. Only when the
direct link from CEP ports to CCEP ports are down will the traffic be re-routed to pass through ICL
link.
ARP broadcast resolution
Assuming that switch A is VRRP-E master router and switch B is the backup router. ARP request (a
broadcast packet) from S1 that is sent through direct link to switch B will be sent to switch A for
processing through ICL link. Since MAC learning is disabled on ICL link, the ARP will not be learned
automatically through the ICL link. When the ARP request is received by switch A, the reply will be
sent through direct link from switch A to S1. If by the time the ARP reply was received the MAC
address for the MCT on S1 is not learned yet, the reply packet may be flooded to both the CCEP
ports and ICL ports.
Both MCT switches are VRRP or VRRP-E backup routers
In Figure 181 , both MCT switches A and B need to ensure packets sent to VRRP-E virtual IP address
can be L2 switched to the VRRP-E master router for forwarding. The MCT switch that has direct
connection to the master router (who actually learned the VRRP-E MAC from the master) will sync
the VRRP-E MAC to the other MCT switch that does not have direct connection to the master. Both
data traffic and VRRP-E control traffic travel through ICL unless the short-path forwarding feature is
enabled.